Kodalide II vs Realist Red Button viewer

There are many stereo Realist format slide viewers from the 1950s. The best ones have achromatic lenses. Some names: Stereo Realist, Kodaslide, Revere, Wollensak, TDC. Realist and Kodak made more that one model. For example, the Realist red button has achromatic lenses while the Realist white button has single element (glass lenses). The Kodaslide I has plastic lenses, the Kodaslide II has coated glass achromatic lenses (day and night difference).

Among these viewers, the question usually boils down this: Which viewer is better, the Realist red button viewer or the Kodaslide II viewer? This question would have raised a war in the 1990s (same as the question "which stereo camera is better, the Kodak or the Realist?") but I don't think anyone cares as much any more. But, in any case, I feel obligated to state my opinion.

I have seen, tested, repaired, all kinds of vintage viewers. The quality of the lenses is one factor, how well the viewer handles or works is another, when it comes to finding a personal favorite.

I have been very happy with Realist red button viewers.  They have excellent lenses, metal rack and pinion and focusing.  But they are fragile and they tend to break if your drop them.  There is some variation in the optics. Some viewers show haze (loss of contrast) in various degrees, due to deterioration of the glue that holds the two elements together. If you find one with crystal clear lenses, then it is a joy to use and, in my opinion, the best vintage viewer ever made.  This viewer can also be widened for 8p so you can  view any image size you like. I offer this service, see: http://www.realistrepair.com/RBRepair.htm
 [By the way, I repair all kinds of viewers so I am not trying to promote this viewer for this reason]

The Kodaslide II viewer has larger and coated "achromatic" lenses, which are, I am sorry to say this, some of the worse achromatic lenses ever put into a viewer.  Just look through this viewer with a black and white slide or no slide just an empty mount, or nothing. You will notice: 1) Distortion (straight lines are bending, this is seen in all viewers but to a larger degree in this viewer), 2) Chromatic aberration (you will see colors at the edges, something that you normally do not see in achromatic lenses). Center sharpness is very good.  The problems show at the edges and you can see them if you look at an empty slide mount (the image just confuses things so just look at an empty mount).

Now, I know that many people love this viewer and are not bothered (or cannot even see them) by these issues.  Some claim that they do not exist. The fact is, these problems exist in every Kodaslide II viewer. I have tested hundreds of viewers and I can assure you that they are all the same, there is no individual variation.  That's fine.  The viewer has a nice friendly shape, the nose fits well, the larger size of the lenses is a plus, and used in AC it has a wonderful warm light. But the focusing sucks and the interocular adjustment and lens holders are all plastic and tend to break. Also, it cannot be widened as easily as the Realist viewer and certainly no wider than 7p (without a lot of difficulties).

In the end, it is all subjective. I had a good friend who loved the Brumberger viewer because it is simple to use, despite the fact that it has single element lenses. Another friend cannot tell the difference in quality between a Kodaslide I and II (to put it mildly, you have to be blind not to see the difference between these two viewers - the Kodaslide II has much better lenses, or, another way to put it, the Kodaslide I must have the worse lenses ever put into a stereo viewer).

The bottom line is that the best viewer is the one that you like the best. For me, this is the Realist red button viewer widened for 8p. Here is my favorite viewer:

Apertures widened to 8p, interior painted white, fitted with a halogen bulb. Through the years I acquired almost every stereo slide viewer ever made, including some very expensive custom-made viewers (by Ekeren and deWijs) but, in the end, this is the only viewer I kept.

For a different take on this, read this “Classic Stereo Viewer Shoot-out Results”: https://groups.yahoo.com/neo/groups/photo-3d/conversations/messages/103374 and feel free to form your own opinion. 

I stand by my opinion:
The Realist red button viewer rules :)

The Macrolist

The Macrolist is a specialized macro stereo camera, a replica of the Macro Realist Stereo camera. It was designed and built by David Burder in England. David is a world-renowned stereo personality who has been involved in many stereo projects, including unique modifications of the Nimslo stereo camera. I estimate that 30-50 Macrolists were built. This makes this camera a rare stereo collectible, in addition to being a very practical camera to use for those interested in macro stereo photography.

Technical Specifications:

• The Macrolist is based on an original Stereo Realist body with a custom lens and shutter assembly.
• Image size is standard 5p ("Stereo Realist format") or 23x24mm. Unlike the Realist-format, the images are side by side (not interlocked). You still get about 29 pairs from a 36 exposure roll of standard 35mm film. The film advance is the original film advance systems of the Stereo Realist camera.
• The lenses are air spaced triplets, effective focal length 35mm, coated optical glass elements. Effective aperture is f/40 and it is fixed. This camera gives a greater depth of field than the original Macro Realist, which is considered an advantage.
• Lens spacing (stereo base) is 16 mm. Field size is approximately 50-65mm and the magnification about 1:2.
• The shutter is a Copal shutter with a full range of shutter speeds. Recommended exposure for the macro pictures is via electronic flash. Focusing is simply done by placing your subject between the two prongs of the camera.
• Compared to other macro stereo systems, the Macrolist is rather “strong”, as you can see from the convergence of 9 degrees so some care is needed to keep stereo deviation in check.

Close-ups with a Stereo Realist – Closer than 2.5 ft

The Realist can focus as close as 2.5ft. If you want to focus closer then you have to either fool around with the focusing wheel or attach close-up (supplementary) lenses.

The limit of 2.5 feet is imposed by the rotation of the focusing wheel, which is limited by a small screw. This screw can be removed (see picture) allowing the Realist to focus even closer. It has been reported that the “second round” of the focusing wheel corresponds to focusing distances from 20 inches (at INF) to 14 inches (at 2.5ft) but testing should be done to get the exact focusing distance. This testing can be done by using a ground glass and a magnifier and observing a test image.

If you decide to experiment with this method make sure you don’t lose track of which round the wheel is at. Also, because the focus plane is pressuring the film, you should turn focusing to infinity before advancing the film.



We discussed close-up lenses in previous postings. With a little imagination you can attach close up filters (or any filters) to your Stereo Realist camera. For example, I have used a film cap with a 20mm hole, with the filter attached to it, over the Realist lenses (see picture). Some people have used the Realist Film ID unit for macro pictures. This unit is essentially a strong close-up lens with the advantage that it attaches to the Realist lenses and offers a holder right at the near sharp focus distance. You must find some way to shift or rotate the subject for stereo relief and you need to move the unit from one lens to the other without disturbing the setup. Sounds like a challenge.



Here is a Table that summarizes key variables when using the +1 and +2 close up lenses with the Realist focused at 2.5 ft.. In-between magnifications can be achieved by focusing the camera further. For example if you use the +1 lens and focus the camera at 10ft, then the actual focus point is at 30 inches (2.5ft) which is the same as the near focus without lenses.

The drawback of these extreme close-up settings is realized when we look at the image loss. Using the +2 lens at 2.5ft focus we lose 8mm of image. This leaves us with 23.5mm – 8mm = 15.5mm of useable image width. There is no slide mount that can mask this (4p/Half Frame/Nimslo mounts have 16mm openings)



One way around this problem is to use prismatic close-up lenses. These have the shape of a wedge and must be aligned over the lenses. In addition to changing the focus, they also shift the image to reduce/eliminate image loss. The drawback is that they introduce aberrations and distortions.

I am familiar with the “Stereo Angle-Lens”, a prismatic close-up lens manufactured by Photo-Liz Inc in Long Beach NY. As seen from the copy of the instructions reproduced here, these filters come in 3 different strengths. Of interest is the “neutral” filter which is a simple prism. This is used to push the window back in close ups without filters or also to push the window forward when taking hyperstereos!

I have tried these filters for an extreme close-up portrait of my daughter. The results were interesting, but the resulting image has too much stretch and distortion for my taste, even when viewed in the viewer.

The bottom line is that for extreme close ups with the Stereo Realist, you need to reduce the stereo base. Some people have used the Realist and a slide bar for close ups. This procedure will reduce the stereo base in a stereo pair, without wasting any film: Cover the right lens, and take the first picture. Do not advance the film. Shift the camera slightly to the left (to reduce the spacing of the lenses). Cover the left lens and take the 2nd picture. I have seen a portrait taken with this method! (The model must stay still for along time). This method might have novelty value, but if you are going to use a slide bar, it is much more convenient to use an SLR camera, not the Stereo Realist.

Close-ups with a Stereo Realist – 2.5 to 7 ft

In the range of 2.5 to 7 ft, all you have to do is point the camera to your subject, focus and shoot. Sounds simple, however, if you want to do this successfully, you have to take certain precautions: First you have to limit your background. Second, you have to crop the final images for the correct stereo window.

I see this in our stereo club. Some people take pictures with objects from 4 ft to infinity. This is too much for me. Such pictures cannot be viewed comfortably in projection. It is also impossible to mount them properly using standard stereo mounts. (Note: Some people attempt to mount such pictures using a technique called “double depth”. This technique eliminates “window violation” while keeping this excessive amount of depth. Personally, I prefer to keep the background a stereoscopic deviation within limits.)

How do you block the background? By altering the composition. For example, put your subject closer to a wall or other natural barrier, use a flash (background is dark), shoot a picture of a dog or cat looking down, etc.)

We can construct a Table which shows the maxium object distance for a certain near distance. I have done this in the previous posting for 4 focus distances. For example, if the near object is at 4 ft (1.2m), the far object should be no further than 10 ft (3m).



As it turns out, you don’t need this Table because it is built into the Stereo Realist’s Depth of Field (DOF) scale. If you line up the near object distance with one of the f8 marks, the other f8 mark will show you the far object distance. For example, in the picture here one f8 mark is at 3ft (near distance). The other is at 5 ft (far distance). (Note: If your Stereo Realist does not have a DOF scale - earlier models did not come with one - I have these for sale in my web page)

I credit Charles Piper for pointing this out. As it turns out, both the stereoscopic deviation and the depth of field have an inverse relationship to the distance. So we can use the DOF information to derive stereoscopic deviation information. There is nothing mystical about this. It is a coincidence that allows us to kill two birds with one stone.

The f8 pointers correspond to 1.2mm, which is generally accepted at the maximum allowable on-film stereoscopic deviation. Charles Piper followed a more conservative approach and used the f5.6 pointers. These correspond to 0.8mm deviation and it is safer for stereo projection (in general, “less is better” when it comes to stereo projection).



When it comes to stereo slide mounting, the image loss will often dictate what image size to use. The openings of the Realist film gate are 23.5mm wide. The 3 relevant RBT slide mount sizes are 21.5mm (5p), 19.5mm (5p close up), and 16mm (4p/Nimslo). So these sizes can accommodate an image loss of 2mm, 4mm and 7.5mm. Considering that film cutter is not always perfect, we should give a margin of 0.5mm, so the three slide mounts will cover an image loss of 1.5, 3.5, and 7mm. These correspond to a near object distance of 940mm (3ft), 556mm (1.8ft, 22in), 333mm (13in).

Close-ups with a Stereo Realist - Theory

The Stereo Realist is designed to take pictures with the near object at 7 feet (2.1m). For “normal” stereo photography, the following advice applies: “Do not let the near objects come closer than 7ft to the camera”. So, before taking a picture, make sure that there is nothing closer than 7ft to the camera.

You can of course take pictures of objects closer than 7ft, and the camera will focus as close as 2.5ft. This is the area of close-up Realist photography. One advantage of the Stereo Realist for Close-ups is that the viewfinder is centrally located and parallax-free. So the framing is always accurate and you don’t need a focusing frame or other aids. You will appreciate this if you try close ups with other stereo cameras. One disadvantage is that distance of the lenses (Stereo Base, 70mm) is too wide for close-ups.

There are two precautions not only for Realist but all close-up & macro photography: As you get closer and closer to your subject, you have to block distant objects. If you don’t, then your stereo pair will have too much deviation and it will be impossible to project and possibly difficult to view in the viewer.

Also, you have to be prepared to make certain adjustments (cropping) in mounting to set the proper stereo window. For the slide film user, this means that you might have to use close-up or half-frame mounts, instead of standard (5p) realist-format mounts.

Without any aid, the Stereo Realist camera will focus as close as 2.5 ft (0.76m), which is surprisingly close (the near focus of most 35mm lenses is 0.9m, or 1m). This near focus can be extended in two ways: The first way is by using a close-up (supplementary) lens. This is a universal way, and can be used with any camera/lens. A +1 lens will bring the near focus to 0.43m (1.4 ft). The second way is Realist-specific. You can remove the little screw that stops the focus wheel at 2.5ft and focus even closer. We will discuss these practical issues in the next posting.

Here are the basic metrics of the Stereo Realist:

Focal Length, F = 35mm

Spacing of lenses (Stereo Base), B = 70mm

Near focusing distance, Inear = 2.5ft (0.76m)

Internal cropping = 1.2mm

This last item needs an explanation: The distance between the film gates is 71.2mm, which is 1.2 mm longer than the spacing of the lenses. This shift is done on purpose to block out a small part of the image (left edge of left image and right edge of right image, remember the images are reversed inside the camera) and set the stereo window at 7 ft.

The Table below gives basic measurements for the Stereo Realist close up photography. I have elected to list the following near object distances: 1) 7 ft, that’s where close up photography starts, 2) 4 ft 3) 2.5 ft (near unaided focus), 4) 1.4 ft (focusing with the Realist at 2.5 ft and +1 close up filter).

I have tabulated the following quantities of interest (all values are in mm):

• Inear = near object and where the camera is focused.
• Ifar = the recommended maximum distance of the far object, in order to keep the total stereoscopic deviation to 1.2mm.
• Back Plane Extension, BPE: The Realist focus by moving the back plane away from the lenses. This value shows you how much the plane is moved back. We have called this quantity x' in our formula derivations here. Mostly a curiosity item.
• Magnification M: This is expressed as a ratio, for example 1/21 at 2.5ft. This can show you the field of view. Considering that the height of the film gate is 25mm or about 1 inch, a magnification of 1/25 means that you can get 25 inches of your subject matter inside the picture. For comparison, a portrait usually requires 12 to 16 inches so the Realist is not really capable for a tight portrait even at the closest focusing distance.
• Convergence: This is the ratio of the stereo base over the near distance, B/Inear. This ratio is 1/30 at 7ft. Values from 1/10 to 1/30 are generally acceptable.
• Image Loss: This is the amount of film that needs to be cropped in order to fix the stereo window. It takes into account the internal cropping of 1.2mm so at 7ft there is no image loss. This quantity is of practical mounting value for slide film users.