Wednesday, July 19, 2017

What’s in My Camera Bag - I

It’s an interesting question… What do stereo photographers carry in their camera bags? I have addressed this topic in two Stereogram Tutorials (a collection of 20 years of Tutorials, available for sale here:
In March 2011 I published a 3 page Tutorial (click to enlarge):

You can download the entire Tutorial here:
In this Tutorial I describe three different times, my “Last Great Film Vacation” in 2009, a visit to New Orleans in 2010 with only the Fuji W1, and a return to New Orleans in 2011 with a lot more gear. Here is what I wrote:

Last Great Film Vacation (Summer 2009)
My last big film vacation was in the summer of 2009.  We went with my family to Orlando , FL.   For this vacation I carried a large camera bag loaded with film stereo equipment.  I had with me: Two RBT cameras (S1, X3), two regular SLR cameras (Pentax ZX-M) for single and twin camera hyperstereos, three pairs of Pentax lenses (20mm, 40mm, 100mm - these can be used with the X3 and the ZX-Ms), a heavy twin camera bar, a compact tripod, two flash units, cables, batteries, and plenty of film.  It was a heavy camera bag but I carried it with me without complaining, took lots of pictures and did very well in the Cleveland and Detroit stereo competitions the following year.
New Orleans 2010
In October 2009 I bought the Fuji W1 and in February 2010 we went (with my wife) to New Orleans to run the local marathon.  For that trip I only carried the Fuji .  I took hundreds of stereo pictures with the Fuji , had a great time and was pleased with the results.  Some of the types of pictures I took include:  1) Hyperstereos from the airplane, 2) Hypostereos at the Insectarium, 3) Pictures before, during, and after the race, 4) Pictures of the city during the day and night.
It was refreshing to travel with only one stereo camera in my pocket.  But that did not last long.  I soon discovered the wired Panasonic cameras, the Macrobox, and various attachments for the Fuji.  My photo camera bag started getting bigger and bigger.
New Orleans 2011
We went back to New Orelans in 2011.  This time I carried the following equipment:
  • Fuji W3 camera with ALA attachment and fisheye lenses.
  • Twin Panasonic TZ10 cameras, wired for stereo.
  • Macrobox with another pair of Panasonic cameras.
  • Panasonic GF1 camera with 40mm and 28mm lenses.
  • Flash, cables, memory cards, batteries.
I then continue to describe why I carry these cameras, how I use them, and to show typical results.
Two years later (February 2013) I published another Tutorial on the same topic:

You can download the full Tutorial here:
In this Tutorial I explain why one stereo camera is not enough for me. For my personal needs I have found that, to cover most photo shooting situations, I need the following:
  • A standard 3d camera for everyday use.
  • A single camera for hand-held hyper- (mostly) or hypo-stereos.
  • Two cameras on a bar for synchronized hyperstereos.
  • A close focusing camera/lens or attachment for close-ups/macros.
Here is how my camera bag looked in 2012:
This table is taken from this Tutorial and summarizes the contents of my camera bag though the three points in time:

This last Tutorial concludes as follow:

"Different people have different expectations and equipment requirements.  As the situation stands right now, no single camera can take the variety of pictures, from macros to hyperstereos, that I like to take, so I elect to carry 4 different systems when I travel.  I did this back in the good old film days and today in the digital era.  One advantage with digital is that I can fit all the equipment in one compact camera bag that does not weigh too much."

From 2012 to Today

There were only minor changes from 2012 to 2016. The GF1 and GF2 bodies were replaced with the GX1 and then GX7. I also stopped carrying the Fuji, in favor of the Panasonic 3D1. I used to say that I do not take any normal stereo pictures. It is either hypo-stereo with the 3D1 or hyperstereo with twin cameras.
I continued along these lines until last year when I discovered the Samsung NX1000 cameras. With these cameras I rediscovered the beauty of “normal stereo photography”, i.e. stereo photography with a base approximately equal to the spacing of the eyes (68mm for this rig).
Because of their normal spacing in the z-configuration and good synchronization, this pair serves as a normal stereo camera and also twin camera with larger stereo base. It is also possible to use one camera for single camera stereo. This drastically changed the contents and size of my camera bag. I will describe this in the next blog.

Tuesday, July 18, 2017

Lenses for Twin Samsung NX camera rigs


In today's digital and phone photography, lenses are neglected. Most compact cameras use a zoom lens and the photographer, using the camera in auto-everything mode, is often unaware of the focal length or aperture selected by the lens. In many cases, maybe this is a good thing: The photographer can focus on the composition and not have to worry about technical details. But there are cases where it pays to know what the focal length and aperture is (or could or should be).

The Samsung NX1000 twin camera stereo system takes interchangeable lenses and also has a variable stereo base from normal to hyperstereo. It is a good system to experiment with different lenses.

There are three sources of lenses for the Samsung NX cameras:
  • Lenses made by Samsung
  • Third party lenses with NX mount
  • Vintage lenses adapted to fit the NX mount
This link describes the NX mount and lists all Samsung NX lenses from Samsung and also third party manufacturers:

Crop Factor

One thing to remember is that the Samsung NX system has a “crop factor” of 1.5x. If you do not know what this means, google to learn more. Here is a good starting point:
In summary, because the sensor of the NX is smaller than full size (24x36mm), the image is cropped (compared to the full size sensor). The end result is that the field of view of a lens when used on an NX camera is more narrow, as if the focal length of the lens is multiplied by 1.5x. The focal length of the lens does not change. This is just a way to compare the field of view of the lens. Since a lot of people are used to focal lengths from full frame 35mm film photography, this helps understand what the sensor sees.

So when you see focal lengths for the NX system, multiply the values by 1.5x to get a value comparable to a full frame camera lens. For example, the standard 20-50mm zoom lens is equivalent to a 35-75mm lens, which is a fairly standard and not very exciting focal length range.
Zoom Lenses by Samsung
These are some zoom lenses that I have tried:
  • Standard 20-50mm f3.5-5.6 (kit) zoom lens. A solid zoom lens that has received good reviews. You need to match the zooms, or find some way to link the lenses. The zoom control rig is easy to rotate. StereoPhoto Maker (SPM) will align images with differences in focal length (just a matter of scale difference), but within limits.
  • 16-50mm f3.5-5.6: This was standard I believe with the NX500. It is a compact lens (see picture below) and attractive for its wider end (16mm) and also because it offers image stabilization (turned ON through the menu, one of the few lenses with this ability). However, it is a motorized zoom lens and does not show the focal length outside or on the screen of the NX1000 cameras, so there is no easy way to match the focal lengths from each camera, other than the two ends. Another kit zoom lens is the 18-55mm lens that came standard with the NX300 cameras, I believe.
  •  50-200mm f3.5-5.6: The longest lens by Samsung, useful for wildlife, long distance action, etc. Does not fit the 68mm spaced camera but most likely it will be used with side-by-side cameras. Here is a picture of me with these lenses. I took some nice bird shots and pictures at a baseball game with these lenses.

The picture below shows the zoom lenses discussed above.  One last comment is that the 20-50mm is the only lens that locks (manually) and needs to be unlocked to use.

Other zoom lenses that I have not tried include the 15-50mm f2-2.8 (note wider maximum aperture than the standard zoom lens), 18-200mm f3.5-6.3, 50-150mm f2.8 (fast fixed aperture).

Matching Focal Lengths: With the 20-50mm lenses, one has to match the focal lengths, if using anything other than the two ends (20mm, 50mm). This is usually done by matching the focal length markings on each lens. This is a bit of a problem in the z-configuration where the left lens is upside down and you cannot see the markings. I have used a marker to mark the back side of upside down lens. Another option is to use some kind of mechanical method to link the zooms. I know a couple of people are working on this. I will update this section when I see an interesting solution.

Zoom vs. Fixed FL Lenses
After using the standard 20-50mm lenses, I decided that I prefer to shoot with fixed focal length lenses, for three reasons:
  1. Fixed focal length lenses are more compact.
  2. They are faster (have a large and fixed maximum aperture)
  3. The focal length cannot be changed accidentally. This is easy to do with the 20-50mm lenses.
 For those who find themselves using the wide and of the 20-50mm lens 99% of the time, why not use the 20mm lenses to get a faster (f2.8 vs. 3.5) and more compact/lighter rig, without worrying about accidentally mismatching the focal length?

An interesting side-effect of using fixed focal length lenses: If I happen to have the 45mm lenses, I change my composition and subject framing, to match the lenses. It is a bit of a challenge to use the lenses that I have on the cameras for any situation I find myself into, and the results are often rewarding (unusual composition, different point of view).

One last comment: I survived 30 years of fixed focal length lenses with my Stereo Realist and RBT S1 stereo camera. Yes, I did try zoom lenses with RBT SLR-type cameras, but soon switched to fixed focal length lenses there too. Zoom lenses are a convenience (carry less weigh, be able to change the focal length to compose better) but at the expense of quality, in my opinion.
Fixed Focal Length Lenses by Samsung
Samsung makes a wide range of compact pancake type fixed focal length lenses:
  • 10mm f3.5 Fisheye: Very tiny!
  • 16mm f2.4, a fine performer
  • 20mm f2.8, has now become my standard lens
  • 30mm f2.0, has received good reviews
  • 45mm f1.8, hands down my favorite lens
These lenses (except for the 30mm lens that I do not own, it is similar in appearance to the 20mm lens) are shown in the picture below.

It is interesting to note that all NX lenses come several colors. The most common are black and white. But there is also pink and silver (the 20mm lens above is silver). The camera bodies also come in different colors (black and white are the most common but I have seen pink too). Some people like to use a different color so they can immediately tell which is the R and which is the L camera/lens. I used to do this too, but not any more. My color of choice for the camera bodies now is white, and black for the lenses.
All these lenses above fit in the cameras separated by 68mm. Two more specialized lenses that I own (these are not pancake, they are both large and heavy):
  • 60mm f2.8 macro
  • 85mm f1.4, great portrait lens but too large and heavy

  [The 20-50mm lens is shown for comparison]
My first two pairs of lenses were the 20-50mm and 50-200mm. My next pair was the 16mm. I found the 16mm too wide for general use, so now I use the 20mm lenses as my standard wide angle lenses.
The Samsung NX 45mm f1.8 Lens

The 45mm f1.8 lens gives me excellent results even wide open. I have several examples on my Phereo account. Here are some advantages of the large maximum aperture (f1.8):
·           Can throw the background out of focus, which is useful for available light portraits:
·           Can be cropped without grain or much image quality loss because of the low ISO and sharp image. This picture was taken at a show at night. It has been cropped a lot and still looks sharp. The fast aperture helped me use a fast shutter speed to stop action, at a reasonable ISO:

·           If you shoot through wires with wide open aperture, the wires disappear. This is what happened in this picture:  I took this at the local museum of Natural History. I was shooting behind a wire link chain fence, not between the openings (which were too small). There are wires in front of the lenses but using the wide f1.8 aperture, makes them disappear. Also, this picture is cropped quite a bit, I was a lot farther than it appears.
2D/3D: An interesting thing about the 45mm lens is that it comes in 2D and 3D versions. The 3D function does not work with the NX1000 cameras (the lens behaves exactly as the 2D version, as a matter of fact my pair consists of a 2D and a 3D lens) but it works with all later models. The lens has an aperture with two openings and the camera takes a sequential pair using a rather small (8mm) stereo base. The settings in 3D are very limited, so this lens as 3D is not of much use for stereo photographers.
Non-moving Front: Another unusual feature of the 45mm f1.8 lens is that the front element does not move when the lens focuses. This is useful when you flush the lens on a glass, or when using polarizers or any graduated filters in the front. If the front element moves, focusing is impaired when the front if flushed on glass and the lenses might not be able to focus. No problem with this lens. For other lenses I use a rubber shade to block reflections and avoid touching the glass.

A Tip for Carrying/Storing Lens Pairs

I used to throw all the lenses inside my camera bag. They would bang each other and get nicked. I have dropped lenses as I pulled them out of my bag. Now I am trying to be more careful and better organized. Here is what I have done:

I have glued together two back lens caps, using superglue (an alternative to superglue is to use double-sided foam tape, which allows you to separate the caps later). I use generic caps. Some of them do not hold the lens well, so make sure you find one that does.

I then attach the matched lens pair to the twin cap. I then use an OP/TECH foldover pouch to store the pair. These are soft, durable, neoprene pouches, that protect the lenses.

For the 10, 16, 20, and 30mm lenses, also 16-50mm zoom, the size pouch is 253 (2.5x3 inches)
For the 45mm lenses (also, the 20-50mm zooms), the size needed is 2.5x4 inches.
For longer lenses (50-200mm, for example), I do not bother.They are too long to keep like that.

Another useful accessory is rubber shades. I prefer foldable rubber shades which work better when I flush the lenses to glass (airplane window, for example). Finally, I use generic lens caps (about $1 each) so I do not worry about losing the original lens caps. 

Here are all the parts taken apart:

It helps that ALL pancake Samsung lenses use the same filter size: 43mm.
Third Party Lenses with NX Mount
Samyang Optics (a Korean company) has made lenses with the NX mount. These also come under different names, such as Bower and Rokinon. Here are some lenses that I have owned and tried:
  • 8mm f2.8
  • 12mm f2.0
  • 85mm f1.4
These lenses have the correct NX mount but are manual focus only. I tried to get lenses not covered by Samsung. The plan was to use the 8mm or 12mm for night/star photography. They are both faster than the Samsung 10mm f3.5 and focusing is not important.  The 85mm was a lot cheaper than the Samsung one but without AF. Unfortunately, unlike the wider lenses, focus does matter for the 85mm especially for portraits, etc.
Here is a picture of some fixed focal length lenses, from left to right:  Lensbaby 5.8mm f3.5 circular fisheye lens,10mm f3.5 Samsung, 8mm f2.8 Rokinon, and 12mm f2.0 Rokinon lens. The Samsung stands out as being the smallest of the bunch.
Vintage Lenses
Most vintage lenses by Nikon, Canon, Olympus , Pentax, Minolta, etc., can be used with the NX cameras using the appropriate adapter. These adapters are inexpensive (often as low as $10). They are basically hollow tubes (no lenses) that serve two purposes:
  1. Adapt the mount (Nikon, etc., on the front, Samsung NX on the back).
  2. Take care of the infinity focus.
Here is how the MD to NX adapter looks. This picture shows three adapters at different angles. The black end goes to the camera. The Minolta lens attaches to the silver end.

Infinity focus should be preserved, but you need to check this. I have found some variations, so I always focus by looking at the screen, not the lens focus markings.
Because of the 1.5x crop factor wider lenses are not very useful (they are heavy and expensive and Samsung has plenty of those). But Samsung  lacks in long lenses so I am using Minolta lenses (with the appropriate MD to NX lens adapter) to cover these longer focal lengths. Here is what I have:
  • 50mm f3.5 macro
  • 85mm f2.0
  • 100mm f2.5
  • 100mm f4 macro
  • 135mm f2.8 and f3.5
  • 200mm f4
All these lenses above fit with the cameras at 68mm separation.
I also have these lenses that I have used for bird photography:
  • 300mm f4.5 and f5.6
  • 500mm f8 (mirror)
Here is a picture of some lenses from my collection:

The 500mm is a mirror type, so it is compact by design. The 300mm lens has a mounting collar which helps ease the tension from the camera. The 200mm lens is about the length and weight of the 50-200mm Samsung lens, but it this thinner and also faster (f4 vs. f5.6).  The 135mm f3.5 lens is really lightweight and a bargain at about $20 used.

These Minolta lenses need to be focused manually (the aperture is also set manually).  Because they are longer lenses, focusing is rather critical. It would be nice to have a system that links the focusing rings of the lenses. One feature I use a lot for critical focus is to magnify the image by pressing the center button in the back - see also:
Here is an example taken with the 500mm mirror lens:

In Summary

Even though the NX system is dead, there are plenty of lenses to use. This includes lenses from Samsung, third party lenses with NX mount, and vintage/legacy lenses with an adapter. I have accumulated a large number of lenses. Come to think about it, after investing a lot of money on lenses and accessories (mounts, remotes, etc.) the price of the camera body has become almost irrelevant. The investment is in the lenses and accessories. The camera bodies are disposable.

My own personal shooting style favors fixed focal length lenses. I like the pancake lenses by Samsung because they are compact, lightweight, of good quality, and can auto focus. The 20mm lens (35mm equivalent) is my standard wide angle lens. The 16mm is used for indoor shots or when a wider angle of view is needed. The 45mm f1.8 lens is used any time that I do not need a wide angle.

If, in a previous life, you used a different system (Canon, Nikon, Pentax, Minolta) and still have the lenses, you can use these lenses with the Samsung NX camera and an inexpensive adapter. For example, if you do not want to invest in the (rather expensive) 45mm f1.8 lenses, an alternative is to use normal 45-50mm f1.7 lenses found used for maybe $20 for most camera systems. You will lose auto focus.

As I was organizing my lens collection, my wife asked me: “Why do you need all these lenses? Don’t you miss shots as you switch lenses?” Yes, that’s true, and that’s one reason to use zoom lenses. But different focal lengths allow you to take different pictures. And the wider maximum aperture allows you to use faster shutter speeds and/or lower ISO.

We are really fortunate to we have access a variety of lenses that we can use with cameras with normal stereo base (Samsung NX1000 cameras in the z-configuration) and I am taking full advantage of it.

Friday, July 14, 2017

Tips for Using the Twin NX1000 Cameras

A friend recently sent me pictures from his NX1000 rig that were hopelessly out of synchronization. I had a few experiences like that of my own too. So, here are my recommendations on how to use the twin NX1000 rig to assure good synchronization:
  • Before You Start: Make sure that both cameras have the latest firmware installed (1.15). Also, do the “Flash Test” (see the blog on this) to make sure that the pair shows good synchronization. Mark the cameras R and L so you always use them in the same way. Also, mark the memory cards R and L to make sure the same card goes back to the same camera. Finally, change the default menu options to choices of your liking. These steps are described here:
  • How to Turn the cameras ON / OFF: These cameras have a peculiarity: If their remotes are connected then when one camera is off, the other camera will fire. It is as if the camera that is OFF acts as a closed switch for the camera that it ON. So, if you turn one camera ON while the other is OFF, after a short time (maybe 1 second or so) this camera will fire. And if both cameras are ON and you turn one OFF, then the other camera will fire. To avoid this, the cameras can be turned ON or OFF at about the same time (within one second). But if they are turned ON too close to each other, then one camera will not detect the remote. (This was explained by Werner as follows: When the cameras are turned on, they send a pulse to detect the remote and if the pulses are too close to each other, one is missed.)

    To avoid these issues, I have turned on the setting to Clean the Sensors at Startup. This gives a bit of extra time to each camera. So I turn one camera ON then the other. Both cameras detect the remotes and none fires. At turn off, I turn both cameras OFF at the same time. Using this simple procedure I get no misfires and no remote problems.
[PS. Others have found other ways around this. One user keeps the lens caps on. This stops the cameras from focusing and if they cannot focus, they do not fire.]

  • Modes to Use: Use these camera modes: P, A, S, M (same mode on both cameras).

Do not use the SMART mode (this delays the camera in an unpredictable way – that was the problem with my friend’s pictures). If using a flash, use a flash that does not communicate with the camera. So, do not use a Samsung dedicated flash (this delays the camera that fires the flash).
  • Focusing and Firing: When taking a picture, half-press the shutter button and wait to hear/see the focus confirmation from both cameras (hear the sound and see the green focus confirmation square on the screen), then fully press to take the picture. If one camera has not focused, it will not fire (this is the standard setting) and this will lead to mis-synchronization. Most mis-syncronization issues happen if you hurry to take a picture without waiting for the cameras to focus first. If you want to speed up shooting and the distance to the subject does not change, then switch to Manual focus.
  • Focus Setting: Make sure that the focus is set at Single Focusing [SAF] (or Manual focus [MF] if you really want to use this setting), and not at Continuous Focusing [CAF]. It is easy to press the center dial and change the focus mode while trying to get out of the menu. At [CAF] the camera keeps looking for focus and it is delayed.

  • Drive Setting: Make sure that the cameras are set to Single Drive and not timer or any other mode. Again, this setting is easy to press and then change trying to get out of the menu. You can use both cameras in other than Single Drive mode, just not only one.
In summary: If you have a pair that has passed the Flash Test, use the P, A, S, M settings, take your time to half press the shutter to focus, and nothing has changed in the focus and drive settings, then everything should be OK. 

In case of trouble: If you notice a problem, lack of synchronization, or any unusual camera behavior, do not panic (“OMG, my cameras are broken!” – this was my reaction when I accidentally changed the focus to CAF and the cameras were clearly firing out of synchronization).  Calm down and examine the settings, make sure that you are using the same mode and shooting variables (f-stop, shutter speed, exposure compensation) on both cameras, make sure that the focus and drive settings are the same. Check that you have not accidentally bumped the zoom or switched to Manual Focus. Turn the cameras OFF and ON. If everything is set properly, the cameras should return to normal.

The Center Dial

This picture shows how to use the center dial. The dial can be pressed in 5 different ways: Center, up, down, right, left, and it also rotates, plus there are 4 buttons at the corners around it. These buttons and controls have different functions depending on whether you are in shooting or in playback mode.

Top Buttons:
  • MENU: In shooting: Brings up the menu that allows you to change shooting variables like ISO, White Balance, etc., and also menu items. After the initial changes, I normally go there to change the ISO or white balance. But these can also be changed with the Fn button. In playback mode you get a different menu.

  • Fn: This bring a menu with all the shooting variables so you can change all variables in one convenient place. That’s a useful shortcut. In playback mode it has options for manipulating the image you have recorded.
Center Dial:
  • Top: DISP: Changes the display. Experiment with this to set the display to your liking. Since you are using two cameras, you can have two different displays, for example, turn the electronic level ON in one of the cameras but not the other. In preview mode you can pull up information about the recorded image.

  • Bottom: Exposure Compensation: Allows you to change the exposure compensation (when appropriate). The same can be achieved using the Fn button, which is a bit easier to see, in my opinion.

  • Right: Changes the focus mode. Remember, you want [SAF] (or [MF])

  • Left: Changes the Drive Mode. Normally you are using Single Drive, the most left setting.

  • Center in Shooting Mode: Pressing the center dial in shooting mode allows you to change the size and location of the focus area. I change this setting when I take close-ups, where I converge the focus area towards the center. This remains in effect even after the cameras are turned off, so if you change it for close-ups and then switch to shooting with infinity, you might want to bring the focus areas back to center. 

  • Center in Playback Mode: In playback mode pressing the center dial enlarges the image to see details. Rotating the dial changes the magnification and you can also move around to see different parts of the image. This is a useful operation that allows you to closely inspect your images to make sure that they look OK.

Bottom Buttons:

  • Playback: Brings up the last image you recorded and you can scroll through by pressing the right or left side of the dial. While in playback mode, the wheel and buttons have different functions than the normal shooting mode.
  •  Delete: Deletes images recorded. If I see that one camera misfired (i.e. only one camera took a picture for one reason or another) then I delete this image at the spot, rather than having to worry about it later. This saves time on image processing at home.
If you have any tips about using the cameras, let me know.

Thursday, July 13, 2017

Putting a twin Samsung NX1000 camera Rig Together

I was asked to put together a twin Samsung NX1000 camera rig using a pair of white Samsung NX1000 cameras with standard 20-50mm zoom lenses, the 68mm body mount, and the single remote cable. Here are the cameras, mount and cable:
[Also shown above is the SD card that I use to install the 1.15 firmware, plus a pair of SD cards that I use to test the cameras.] 

I documented the procedure for future reference:
Test each camera: Since most cameras are bought used/pre-owned or refurbished, I recommend testing each camera when it is received: Charge the battery, turn the camera on, reset the menu, and take some test pictures to make sure everything looks OK. Also, test the remote plug to make sure it is working.
Mode Switching: A peculiar issue has been reported with some of these cameras. When the mode switch it touched, the camera switches modes. This can be a big problem when shooting because while the camera is switching modes, you cannot take pictures. An extra problem in stereo is one camera selecting a different mode than the other, throwing the pair out of synchronization (if a mode other than P, A, S, M is selected) or resulting in different exposures. I had several cameras that showed this to various degrees. Here is a solution: Spray a contact cleaner around the switch (Ray Moxom recommended a product called CRC 2-26), turn the switch around for the cleaner to make its way to the contacts. This has solved the problem for me. The problem might come later so you might need to repeat this, but the situation is manageable.
Install the latest firmware (1.15): It has been reported that this improves synchronization. Google to find the files and follow the directions. Note: Installing a firmware resets the menu so don’t make any menu charges before you install the firmware because you will need to do it again..
Perform the “Flash Test” to get an idea about the synchronization of the pair and decide which is will be the right (R) camera and which will be the left (L) camera. This test is detailed here:
After this test, mark the cameras R and L.
Change the Menu Settings: Different people have different preferences. I am open to suggestions. Shown in this figure are the settings that I change. The figure shows the default settings after a camera reset. My changes are described below.

There are 5 menus. I will describe the changes as you move through the menus from left to right:
Camera 1: Change quality from F (Fine) to SF (Super Fine). There is no reason not to use this Super Fine setting to get he highest quality JPG files.
Camera 1: An interesting setting is called “Framing Mode” which is OFF by default. When the exposure is dark (using a flash, for example) the display will be dark. By turning this setting ON, the display brightness is constant regardless of the camera settings, so you can frame the shot better. I like to have the framing mode ON on the R camera and leave it OFF on the left. This way I can frame and still have an idea of what the ambient exposure is when I use flash. I discuss this in my flash blog:
Custom 1: I like to turn the Noise Reduction OFF. If this setting is ON, then after a long exposure the camera will process the images to reduce noise, which takes time. I learned this the hard way when I was shooting fireworks one night. Most people agree that, if needed, noise reduction can be done later with software.
Custom 2: I like to turn the 2x2 grid ON. It helps with composition and alignment of the cameras.
Settings 1: This is the menu to reset the menu, format a memory card or change the file number. Regarding the file numbers, I like to initialize the right camera’s file numbers so the numbers from the two cameras do not overlap. If they overlap, StereoPhoto Maker cannot do autolignment and the files must to be renamed. Having totally different file numbers avoids this extra step. The aligned pair from SPM uses the naming of the L camera so it is OK to initialize the R camera’s numbers.
Settings 2: First, I turn the “Help Guide Display” OFF because it drives me crazy. This is the first thing I do when I change the menu. Then I change the Date & Time. I finally change the different times as follows:
- Quick View: I increase it to 5 seconds because I like to have more time to inspect the picture. (One can consider put it on Hold)
- Auto Display: I leave it at the fastest time of 30 seconds, to preserves battery.
- Power Save: I normally increase it to at least 5 minutes because I do not want the cameras to turn off too often. If the cameras turn off because of inactivity, I turn their switches to OFF and ON again.
Settings 3: Sensor Cleaning: I turn the Sensor Cleaning ON at startup. This gives me time to turn the two cameras on one after the other, without one camera firing. I discuss this in the blog on how to use the cameras.
One last but important setting that needs to be changed:

In preview mode, press the menu to go to the Playback menu, in the second screen, change the Auto Rotate of the Left camera to OFF. By doing this, when the cameras are in the z-configuration (with the left camera upside down) the preview image is straight. This way it is even possible to freeview the R and L images. I guess you could change both cameras, it does not matter.
Test the camera pair: With the cameras tested for synchronization and the menus adjusted, I test the cameras by taking pictures at different settings, including flash. If everything looks OK, then I do the last step.
Remove the (closest to the lens) lug strap: This is only needed if you want to get the cameras as close as possible (68mm). It should be done last because if there is a problem with the cameras, you cannot return them or sell them for 2d use with the lug removed. In my first pair, I tried to disassemble the camera to remove the lug. Even though I had directions, the operation was too involved with lots of parts needed to be taken out, so I gave up and just cut the lugs off. Here is how I do it:
I use a pair of metal snippers and a rotary tool with a cutter bit. First, I cut the lug. Then I use the rotary cutter to remove the remaining metal and make it smooth. After this is done, the cameras can touch each other.
With the lugs removed, I connect the cameras with the body mount and the remote cable. I put the cameras on a steady support and zoom at the long end of the lens (50mm). I then adjust the cameras to achieve good alignment and tighten the screws of the mount. See details here too:
The final camera rig is ready to go:

Wednesday, July 12, 2017

Flash Test for twin NX1000 Synchronization

A simple way to get an idea about how well a pair of Samsung NX1000 cameras synchronizes is to use the “Flash Test.” This test will also allow you to decide which camera will be the right (R) and which will be the left (L). It will also help you understand how flash synchronization is achieved and what can go wrong.
First, look at this timeline (click to enlarge) of flash use for twin cameras with mechanical “focal plane” shutters (which is what the NX1000 has).

In these cameras there is a mechanical shutter and the flash fires only when the shutter is fully open. The shutter has two curtains, the front and the back, that travel vertically (in the NX1000). The time needed for the shutter (front curtain) to open determines the “flash synchronization speed” which is the fastest camera speed for which flash can be used. For the NX1000 this speed is 1/160s. This is about equal to the speed that it takes for the front curtain to open, exposing the entire sensor to light.
At instant 0 the camera receives the signal to fire the shutter. There is a very short delay (known as “shutter lag”) and the shutter starts to open at instant 1. The shutter is fully open at instant 2. After a very short delay, the signal is given to fire the flash (3A if the flash is fired at the start of the exposure). If the shutter speed is slower than the flash synchronization speed, then the shutter will remain open until 4, to satisfy the exposure. Then the second curtain will start to move (shutter starts to close) and at 5 the shutter is fully closed and the exposure ends.
This is the timeline for the camera firing the flash. If there is a second camera involved (as it is in stereo) then the question is, when the flash in camera #1 fires, what is the status of the shutter in camera #2?  When camera #1 fires the flash, what does camera #2 sees? (Camera #1 always sees the full flash exposure since it triggers the flash).
There are three possibilities, as seen in this figure:

  • A: The shutter of camera #2 is also fully open the camera sees the entire flash exposure.
  • B: Camera #2 is “slower” (has larger shutter lag) so when the flash fires, the shutter is partially open. In this case, camera #2 will see a partial flash exposure.
  • C: If there is a large lag difference between the two cameras, it is possible that when camera 1 fires the flash, the second camera’s shutter is still closed. In this case, camera #2 sees no flash exposure (image is dark).
Based in these concepts, here is how the flash test works:

Flash Test

Step 0: First, make sure that both cameras have the latest firmware (1.15). It has been reported that this helps improve synchronization. Connect the cameras (their remote plugs), using a method of your choice.
Step 1: Put both cameras in Manual mode (M) and 1/160 speed. The f-stop and ISO are not important. I use f4 and 100 ISO.
Step 2: Put the flash on camera #1, fire the cameras (the flash should fire) and note what camera #2 sees (camera #1 fires the flash so it sees the entire flash burst). There are three possibilities for camera #2: F: Camera #2 sees the full flash exposure, P: Camera #2 sees a partial flash exposure, N: Camera #2 sees no flash (misses the flash exposure).
Step 3: Switch the flash to camera #2 and note what camera #1 sees.
Possible outcomes of this test:
  • A. Both cameras see the entire flash exposure, no matter which camera fires the flash. This is as good as it gets. I estimate the synchronization of this camera pair to be in the order of 1ms (1/1000s) or better.
  • B. One camera consistently sees a partial flash. This camera is “slower” (has longer shutter lag), so when the flash fires, the "slower" camera's shutter is not fully open. An estimate for the synchronization of this pair is 5ms (1/200) or better (often closer to 1/500), which is still acceptable for me.
  •  C. One camera consistently misses the flash. In this case the synchronization is worse than 5ms (1/200). This is a situation that I do not see very often (I think I only saw it on one pair, but that was before checking the firmware on each camera). In this case, I will try to find another pair.

The picture above shows situation B. The right camera fired the flash. When the flash fired, the left camera's shutter was not fully open, so part of the image is dark.  (This picture also shows that in the NX1000 the shutter travels vertically, and opens from bottom to top.) Here is an estimate of the mis-synchronization of this pair:  The time it takes for the shutter to open is at least 1/160s (6.25ms). Probably it is a bit shorter, let's say 5ms. About 2/5 of the shutter has not opened yet. So, a rough estimate is that the two cameras are off by 2ms or 1/500s. That's not bad at all for most shooting. (PS. This is a stereo pair but the cameras are side by side aiming close so the stereo base is excessive, do not try to freeview it.)  

The figure below is a variation of the previous one, applied for the NX1000 pair and summarizes the test and possible outcomes when using flash with the twin camera pair. In this figure I recommend starting the test at 1/100 but I have found little difference vs. doing it at full flash synchronization speed (1/160).

Designate R and L cameras: If one camera is slower than the other, make the slower camera fire the flash (for me, this will be the R camera). If the slower camera fires the flash, the flash will be seen by both cameras. So this test can also determine which camera should be the R and which should be the L. In the pair with the partial exposure above, the left camera is slower (shows partial flash exposure) so it should be the one firing the flash (which for me will be the R camera). When this camera was firing the flash, I was getting 100% flash success.

Our of curiosity, I wondered if I could capture a picture showing a band of light and dark top and bottom. This would be the case if the front curtain is opening while the back curtain is closing. For that to happen, the shutter speed must be higher than 1/160. In the example below, the right camera is set at 1/160s to fire the flash but the left camera is set at 1/1000. At this fast shutter speed, the back curtain starts to close before the front is fully open and the flash froze the action while both shutters are in motion. (PS. This is also a stereo pair with a normal stereo base, so it can be freeviewed)

Final Note: If flash exposures are important, they could be improved using the “Magic Flash”. This is a device made by Rob Crockett. See:
The Magic flash can guarantee flash synchronization as long as there is an overlap in the time the two camera shutters are open (so use 1/125 shutter speed, or slower - do not use 1/160).
I have found the Magic Flash to be useful with other Samsung NX cameras which do not show as good synchronization as the NX1000. Also, for other digital cameras (Panasonic, for example) that do not show good synchronization, due to “flash induced shutter delay.”

Monday, July 10, 2017

Flash with the Samsung NX1000 twin camera rig

[Last Update: July 20, 2017]

Flash use was a pleasant surprise with this rig because… it works!!

I am often asked: “How do I turn the Flash On in these cameras?”
Answer: You do not. The two basic principles of flash use with a pair of twin NX1000 cameras are:
  1. Use a non-dedicated flash and attach it or connect it to one camera.
  2. Make sure that the shutter speed is less or equal to 1/160s.

If these two conditions are met, then the flash should fire.
Here is the rest of the story:
1. Use a simple (non-dedicated) flash.  If you use a dedicated flash, i.e. a flash recognized by the camera, then the camera firing this flash will be delayed (I call this “flash induced delay”), and synchronization will be lost. If you really want to use a dedicated flash (like the small flash that comes with the camera), you can use two flashes, one on each camera. Then the “flash induced delay” should be the same and you might get OK results. I do not recommend using two flashes (one on each camera). It is confusing and the shadows can be strange. Just use a simple flash, not recognized by the camera.
2. There is no camera flash setting to turn on. The camera will fire any flash attached to it, as long as the shutter speed is 1/160 or less (this is the flash synchronization speed). If the speed is faster than 1/160  (for example, 1/200) then the flash will not fire. Nothing will happen. If the flash is 1/160 or slower (for example, 1/100) then the flash will fire.
There is no indication by the camera that a flash is attached to it. It is as if the camera is totally unaware of the existence of the flash and this is a good thing because I believe it makes flash synchronization possible. Often, when the camera detects the presence of a flash, the shutter firing is delayed and synchronization is lost. That's the case with the Panasonic micro 4/3 cameras and synchronized flash with these cameras is problematic.
Note: Any vintage or modern flash should work with these cameras. If using a vintage flash, make sure that the flash voltage is safe (older units use high voltages that might damage a modern digital camera). There have been reports that some flash units are not fired by the NX1000 camera. The only flash I have found not to work is the Nishin i40. I do not know why this is happening but if you put the camera at 1/160 (or slower) and the flash does not fire, then you might have found another unit that does not work.

Physical Connections

For the flash to fire, the center contact of the flash must connect to the center contact of the camera. The extra contacts (on flash or camera) are used for flash dedicated functions and are not used here. They are usually not a problem.

There might be some issues with the physical connection, depending on how the cameras are supported. Some flashes hit the mount (the Werner body mount, for example, see below) and not make good contact with the camera.

In this case you might need a flash adapter that simply raises the flash higher while maintaining the center contact. Any flash adapters or flash accessories can be used with this camera rig. I show one in the picture above. I get these from ebay.

When I use on-camera flash, I always attach it to the right camera, which is the natural choice for the z-mounting configuration. There is also the possibility of using a flash off camera, connected either with a cable or wirelessly. In this case, you have to worry about how the cable or wireless receiver attaches to the camera.

Flash Exposure

So, you have a flash connected and fired by one camera. How do you control the exposure? This is a general flash question, not specific to the Samsung NX1000 twin rig. But a lot of people are not familiar with flash use so I will review the basic concepts.

Flash exposure is controlled by:

  • The flash (it controls the amount of light emitted by the flash) and 

  • The camera (it controls the exposure of flash and ambient light). Ambient light is any light in the scene, not coming from the flash.

There is nothing new about that, this is how flash always worked, even when using a 1950s Stereo Realist. The main difference between film cameras and digital cameras, when it comes to flash exposure, is that with film cameras the ISO (speed of the film) is fixed and cannot be changed from one picture to the next. With digital cameras the ISO is an extra variable and can be changed at will.

The question is, how do you set the flash and how do you set the camera to get good exposures?
Camera settings

There are three camera settings that affect exposure:
  • Shutter Speed
  • Aperture
  • ISO (fixed with film cameras, variable with digital cameras)
Because flash duration is very short, the camera shutter speed has no effect on flash exposure. Flash exposure is only affected by the aperture and the ISO setting.
I recommend that you fix the ISO when using flash so it is not an extra variable. You can use for example ISO = 100 or 400. If you fix the ISO, only the aperture will affect the flash exposure. Then use the shutter speed to control ambient exposure. For example, you can use ISO = 100, f = 5.6 and get good exposure with flash. Then if you use 1/160 shutter speed (the fastest possible), you will minimize the amount of ambient light. If you use a slower speed, you will admit more ambient light.
The NX1000 camera can be used in one of these settings:

  • P (Program): camera sets both aperture and shutter speed to satisfy exposure.
  • S (Shutter Priority): you fix the shutter speed and the camera selects the aperture to satisfy the exposure.
  • A (Aperture Priority): you fix the aperture and the camera selects the shutter speed to satisfy the exposure.

In any of these settings (P, S, A) you can override the camera’s choices by using the exposure compensation. Setting exposure compensation to +1 results in the camera overexposing by one f-stop. Setting it at -1 results in the camera underexposing by one f-stop, etc.
  • M (Manual): you set both the shutter speed and the aperture. With the ISO fixed, the camera makes no choices and you have full control of the exposure.
In addition to these 4 basic modes, the ISO is set independently, either in AUTO (the camera decides what value to use, to satisfy the exposure) or at any fixed value (100, 200, 400, etc.)

When using flash, my personal recommendation is set the cameras in Manual mode. This is the easiest to understand and gives you full control of the exposure. Fix the ISO (set it at a fixed value, not AUTO), set the shutter speed at some value of 1/160 or slower. Then, the aperture would be the only variable that affects flash exposure. Change the f-stop to get good flash exposures. If needed, tweak the ISO. Only change the shutter speed if you want to balance flash and existing light.

It is also possible to use S, A, or P modes, but be careful. The camera will select settings for the ambient exposure, without taking flash into account, which will most likely lead to overexposure. You might need to use Exposure Compensation to reduce ambient exposure to balance with flash. It is a matter of trial and error.
One interesting camera setting when using flash is the Framing Mode:
This is normally OFF. When the ambient exposure is dark (this happens when using flash, for example, with settings that give good flash exposure, in which case the camera only shows the ambient exposure) the display will be dark, or even totally black, so you will not be able to frame your subject. By turning this setting ON, the display brightness is constant regardless of the camera settings, so you can frame the shot better.
I like to have the framing mode ON in one camera and OFF in the other. In the picture above it is turned ON on the right camera. The settings for this picture (Manual Mode, f4.0 1/69 ISO 200) result in a picture underexposed by about 3 f-stops. The left camera shows the correct (ambient) exposure while the right camera is brighter, to allow for better framing.
By using a different setting on each camera I can frame the picture and still have an idea of what the ambient exposure will be, when I use flash. Best of both words and possible with stereo photography!
White Balance?

How about the white balance setting when using flash? Some people recommend using the "daylight setting" instead of "Auto Balance." That's because the light from the flash has a daylight balance. I have tried both and don't see much difference. But like exposure, maybe it is better to specify the color balance, instead of leaving it up to the camera to decide.

Flash Exposure - Guide Number

Flash units have controls that adjust the light output from the flash. All flashes can be fired at full power. This is the most light that can come out of the flash. A larger, more powerful, flash, emits more light.

There a quantity that measures the maximum amount of light that a flash can emit. This is the Guide Number (GN). You can read more about the Guide Number, here:

The guide number is defined as: GN = f-stop x distance
It is expressed as a distance @ given ISO. For example, 20m @ 100 ISO.

Here is how you can use the GN: Say a flash has GN = 20. You have the camera set at f4 @ 100 ISO. From the definition: GN = 20 = f4 x distance. Solving for distance = 5m. So, if an object is at 5 meters from the camera, it will receive the correct exposure. You can do this the reverse way. Say, an object is at 10m from the camera. What f-stop should we use to get good exposure?  Solving for the f-stop, we get f = 2.

In some flashes (usually older) there is a Table in the back, showing how to set the f-stop with distance. This is the Guide Number, expressed as a Table. Here is one example:

This flash has a GN of 20m @ 100 ISO. I drew the lines at ISO 100 and f4. You can see that if the camera is set at f4 then the object distance for good exposure is 5m (16 ft). Reversely, if an object is at 5m, then the camera should be set at f4 for good exposure. Other combinations are possible too. The Table is basically a graphical expression of the Guide Number.

Note: This flash also has two Auto modes, discussed below.

Flash Exposure Control: Manual - Auto - TTL

The Guide Number, discussed above, expresses the full power of the flash. But flash is often used at less than full power. Most flash units usually have 3 exposure-related modes, that control the amount of light emitted from the flash:
  • Manual: The flash outputs a fixed amount of light. This can be the full power of the flash or a fraction of it (1/2, 1/4, ... 1/64) if the flash has this capability.
  • Automatic: The flash has a sensor that detects the light reflected from the scene and stops the flash output when the exposure is satisfied. Usually, there is a choice of f-stops (for a given ISO). You select a given Auto mode (f-stop at, say, 100 ISO) and then set the camera at this ISO and f-stop. The flash will then control the exposure. Ambient light can be controlled by changing the shutter speed (at or below 1/160). I find this useful. For example, I set the flash at, say f5.6 AUTO mode, the camera at f5.6 and then the exposure is controlled by the flash and it is good for different subject distances or when I bounce the flash.

Example: The Metz 20 C-2 flash shown above has two Auto modes, marked f2.8 and f5.6. Here is how to use the flash in these settings: At 2.8 set the camera at f2.8. The camera will stop the flash when exposure is satisfied. There is a limit of distance that this works. To find this limit, draw a line from 2.8 until it meets the ISO 100 line and read the distance above. This gives 7m or 23ft. Another way to figure this is to divide the GN by the f-stop: 20/2.8 ~ 7m. What this means is that the flash can only illuminate objects as far as 7m. Same concepts apply for the 5.6 setting. Note that these calculations apply for ISO 100. If you use ISO 400, then double the f-stop setting, so the 2.8 becomes 5.6 and the 5.6 becomes 11.

Note: The auto setting does not work well if you take the flash off the camera, unless if the flash sensor can remain on the camera (this is an accessory or an option in more advanced units).
Unfortunately, even though Auto mode was common in older flashes, modern units tend to omit it because they have replaced it with more dedicated modes (TTL, see below). But these modes are not useful for our stereo camera rig.
  • TTL (Through the Lens): The flash communicates with the camera. This mode is not useful here because you should not use a dedicated flash.
My recommendation: For successful flash photography set the camera in manual mode (M) and fix the ISO. Set the flash in manual mode. Set the shutter speed at some value at or below 1/160. Then control the flash exposure using the f-stop and/or the flash output. Control the ambient light (if any) using the shutter speed. Use trial and error (take one picture, judge the exposure, make adjustments, take another picture, repeat). That’s the best starting point.

For Best Results: In general, direct on camera flash is the worst way to use the flash. One exception is for fill-flash, outdoors, etc. Try to bounce the flash, use off-camera flash, or multiple flashes. Balance ambient light if possible or desirable. For bounce flash, a lot of power is lost. That is not a big problem today, even when using compact units with digital cameras: Use the widest possible f-stop and a higher ISO value. Experiment! Trial and error. Shoot, adjust, repeat.

Flash Units that work with the twin Samsung NX1000 rig
Depending on their size, I classify flashes in 3 groups:

Large: Usually used for studio work or by professionals for weddings, etc. They are large powerful units (GN of 70m @ 100 ISO, or higher) used off camera, and usually have external power packs. I used a Quantum Qflash and now I use a Bolt (Chinese made) VB-22 flash.

Medium: They typically take 4x AA batteries, are of average size, and can attach to the camera’s flash shoe. Typical guide numbers: 25-50m @ ISO 100. They are usually heavy, often weighing over 1 lb (with batteries) or 500g. This is the most popular compact flash size, and there are many choices in this group. You can get a new unit made in China for $50 or so. These units usually offer:
  • Variable Manual mode
  • Option to be used in (optical) slave mode.
  • Bounce flash

An example of a simple Chinese-made unit (Bolt VD-410) is shown above. This is a non-dedicated unit with variable manual mode, optical slave mode, and bounce head. The controls on the back are simple and controlled by buttons or dials. They are more advanced/expensive units, offering a few more features like zoom head and LCD displays. Some of these units are dedicated to specific cameras, but that does not matter here as long as the unit can be used with non-dedicated controls (manual mode, etc.)

You can also buy older used units by Nikon, Metz, etc. with similar, or more features (AUTO mode, stroboscopic mode, zoom head), for about the same price ($50-$100). Some of these units are already 30 years old. They cost a lot of money (typically $300 or more) when new. The built quality is excellent and they should easily last for another 30 years. Again, the fact that these units are dedicated to Nikon or other cameras, does no matter, as long as they have controls for manual or AUTO use.

Here is one of my favorite vintage flash units, the Metz 54 MZ-3.It has a standard form, bounce head, LCD display. It has all kinds of modes, manual of variable output, auto, slave, stroboscopic. It has a little rotary wheel that allows you to select settings quickly. Also, it has a secondary flash head in the front for when using bounce (it can be turned off). It also takes different modules for different cameras. You only need the manual one with one contact, but any others will work too. It is a nice unit, but I find it too heavy for every day carry.

So, what is it going to be? A new Chinese flash or an older Nikon, Metz, etc.? The choice is yours.
Small/Compact: These units take 2x AA or 2x AAA batteries (or a single or two lithium batteries) are lightweight and compact and are better suited for casual use or travel. Typical Guide Numbers are 10-20m @ ISO 100. Their weight can be as low as 100g. These are the units that I usually carry, because I like to travel light. You can even have two of these and use one on the camera and the other as slave flash.  Some favorite units are shown here:

  • Nikon SB30: A nice compact & light weight (it only weighs 100g with a battery, which is approximately the weight of a pair of Samsung batteries), loaded with features:
- Sticks up so it is not blocked by the Werner mount (no adapters needed)
- Guide number of 16m @ 100ISO
- 4 Auto modes (2,8, 4, 5.6, 8 @ 100 ISO)
- 3 manual modes (1/1, 1/8, 1/32)
- Exposure compensation +1/2, –1/2
- Exposure confirmation (when used in Auto)
- Optical slave (at full power)
- Everything is controlled by dials, so very easy to set and see at a glance, after you become familiar with it. Also, very rubust (dials don’t fall out, labels do not rub off).
- Wide angle diffuser build-in (retracts or extends in place).
- Infrared filter build-in (this is useful if using on-camera flash, to trigger slave flashes, and you do not want the SB30 to contribute to the exposure).
- Runs on one CR123A lithium battery. This for some people is a disadvantage, as it is not easily available. The battery however is tiny, about the weigh t of a AAA, but a lot smaller, and more powerful - you can buy these for ~$1.50 each.
- Tilting flash head, so it could be used for macro, for example with the Panasonic 3D lens.

The only thing missing is manual firing (it is strange that you cannot fire the flash manually). You can find these on ebay.... Expect to pay around $40.This little guy is a keeper. You can download the instructions here:
  • Sunpak PF20XD: Very nice unit, runs on 2x AAA, has Manual and Auto modes and also can be used as slave. No bounce. This is not made any more and it is not easy to find. The picture below shows the back of this flash and how the controls are laid out. I like this layout because I prefer dials over LCD displays. The only thing I do not like is that the sliding switch that selects slave or on-camera use is not easily accessible.

  • Metz 20 C-2: Nice compact unit runs on 2x AA. Has two Auto settings (no variable manual, only full power). The head can bounce up and I use this feature often (I also use a white card to bounce flash forward, see picture below).

    It is also available under the “Bolt” name (Bolt VS-210) and it is made in China. I use this flash quite a bit, to bounce the light off the ceiling. It works well in the Auto mode where I do not have to worry about changing the settings of the camera or flash. I just fix the f-stop of the camera and shoot.
  • FlashQ Q20: This is an interesting unit, a dream come true in some respects. It runs on 2x AA batteries, weighs only 110g, has variable manual mode (also Video mode – constant variable light) and bounce up head. It also has a slave mode. The big attraction is that it can be separated from the base and fired as a radio slave. Both the bounce and the off-camera flash are useful for better flash pictures. While any flash can be used off-camera using a wireless flash trigger, the attraction here is that the trigger is built into the flash design and it is very small.

This now has be come my to-go unit and I am still evaluating it. For more information, see this web page:
And watch these videos:

Slave Flash

Slave flash is attractive because you can position the flashes at will, fill shadows, modify the scene, and do this without any wires, everything controlled from one flash. Most units discussed here can be used as slave flashes. But there are also dedicated slave flashes. One unit that I like is the one shown below. It goes with different names, like "Mini Slave Wide" by Morris, and (recent incarnation) Holga 006S. Some older units work on 2xAAA batteries (I prefer these because they are smaller and lighter) but most recent units work on 2xAA.

Part of the attraction for me is that the head is like "Bare Head" type, meaning it is not modified but spreads over a wide area. Also, you can remove the top (it unscrews) and easily modify the light, install filters (the Holga unit comes with a set of filters).

One drawback of this unit (and others) is that slave mode only works on full power, so there is no control to reduce the light. You can cover the head with tissue paper as a way to reduce the exposure.

Two examples of pictures where I used slave flash:

The top one as taken by looking down at the slave flash.The bottom one was taken with a slave flash inside the shoe. In both cases the slave was triggered by a on-camera flash.

Flash Synchronization
One subject not addressed here is how the flash synchronizes with the pair of cameras? This is of course a very important question for stereo photography. I am addressing this topic in this blog: