Leica stereo

People like me who have two eccentricities - stereo photography and Leica equipment -- can combine them in several ways using a digital M. Leica made a Stemar twin-lens device with a prism separator attachment ("beam-splitter"), though they're not easy to find. I got one at an auction. For macro shots I bought an extra dedicated Stemar hood on eBay and epoxied on a step-up ring that takes Elpro closeup lenses.

Zeiss Ikon made something similar, the Stereotar, which is cheaper and more widely available, but requires a Contax-rangefinder-to-M adapter--and it has to be for the external Contax RF bayonet, not the internal one. I modified one of the Chinese adapters from eBay, and Rafcamera is now making them. There are dedicated close-up lenses of various strengths.

Zeiss Ikon also made a standalone splitter, the Steritar , which can be screwed on to a lens (35mm works best) with a 34X43 step-up ring or Rafcamera's 34X49dedicated adapter. It's cheaper and widely available, though with some compromise in image quality.

The side-by-side half-frame portrait-mode images are easily processed by Stereo Photo Maker Pro. With the high resolution of Leica digital rangefinders (60 mpix for the M11), the half-images have plenty of resolution, even after cropping.

I've made many stereo images with these setups (identifiable from the EXIF metadata, manually entered with Directory Opus). Here is a sample, compressed and reduced in size (the originals and many more are displayed in my web galleries ). From Cape Cod :

Here are some still lifes :

And here are some from Yosemite :

For many more, see my galleries of stereo photos: https://www.stevepinker.com/Stereo

Even with the images scaled down ( from the M11 60M pixel sensor ) they look sharp.

For parallel viewing I use the Loreo Pixi 3D viewer with the images displayed on my PC monitor. It is low cost and very effective.

Yes, I worry about that when I post stereo images. I've found that people can learn to free-fuse parallel images more easily than cross-eyed ones, and as someone who has never been able to fuse cross-eyed pairs, I admit that I have a bias against them!

On my website I include instructions for viewing stereo pairs; I include the link (and text) below. I strongly recommend a viewer--easier to view, larger images, in sharper focus. I've tried them all, and list my favorites in the instructions. The one I most recommend (combining optical quality, ease of use, and availability) is the Stereo Wide-View Viewer: https://www.amazon.com/Stereo-Wide-View-Viewer-Prints-Monitors/dp/B07DQT8QD6/ref=sr_1_4?crid=2V06YU2KG28O3&keywords=stereo+viewer&qid=1663709012&sprefix=%2Caps%2C94&sr=8-4

My instructions:

https://www.stevepinker.com/Stereo/How-to-view-stereograms/i-sFxSvmS/A

Free fusion (no equipment, some effort):

1. Shrink the browser window so the two images are no farther apart than the distance between your eyes.
2. Relax your gaze so that you’re looking “through” the screen and seeing double.
3. Let the inner pair of the double images drift together and overlap until you’re seeing 3 images, not 4.
4. Keep looking; the center image will pop out in depth.

With a viewer (easier):

• NVP3D Stereoscope: Best, but available only from NVP3d.com/en/shop.
• Stereo Wide-View Viewer, aka Pocket 3DVu: Excellent; available from Amazon.com, Berezin.com, Walmart.com.
• Pokescope: Pretty good; same sources.
• Loreo Pixi: Cheap & compact, OK; same sources.
• (Not recommended: Plastic lorgnettes, Google Cardboard.)

No need to shrink the window; easy to follow (2)-(4).

I agree that that the Loreo Pixi is very good -- compact and affordable. The Stereo Wide-View viewer gives a wider field of view, and the NVP3D has the best optical quality, but the Pixi is pretty usable too.

Pictures could have been great if not in such a low resolution... Why the picture dimensions are so small? I view them in the viewer that I have made, where I use Sony Xperia Z5 Premium that has a screen with 4k resolution, and also macro lenses or 6x6 loupes.

I down-res'd them just for the posting, afraid that the site would not accept 60-meg files! The full-res versions are available here:

https://www.stevepinker.com/Stereo/Cape-Cod-Stereo-II/

https://www.stevepinker.com/Stereo/Still-Lifes-Flowers-Hummingbird/

https://www.stevepinker.com/Stereo/Yosemite-stereo/

https://www.stevepinker.com/Stereo/Cape-Cod-istereo-I/

Thanks for your interest!

Which monitor is it? Does it require a dedicated viewer? And does it easily display side-by-side images like the ones I posted and have on my website?

Thanks!

Thank you -- that's interesting and helpful.

Hi, Francesco,

RAFCamera makes not just a 40.5mm to 49mm adapter, but also a 34mm to 49mm adapter. My Steritar has 34mm threads, so I bought the second. But of course there aren't many Leica lenses with 49 filter threads (there's the APO-Telyt 135, but that's not suitable for stereo). So you could get a 39-49 or 46-49 step-up ring, which allows attaching a Summilux or Summicron.

The problem is that the RAF adapter is quite thick and puts the Steritar far from the camera body, which introduces several optical problems, and the step-up rings push it still farther. (Also, its internal threads are brass, which causes internal reflections.)

A better solution, I found, is to attach a 43mm-34mm step-down ring to the Steritar (it threads on smoothly and securely, even though the pitch is slightly different). I then attach my Zeiss Biogon 35mm f/2 -- an excellent lens, equal in optical and mechanical quality but cheaper than a Leica.

Alternatively, you could attach a 43-46 or 43-39 step-up/down ring, though again, that pushes the Steritar a bit farther from the camera.

The disadvantage of the step-down ring solution is that the Steritar does not screw down to a horizontal position, so you have to screw it in only until it is horizontal. It won't fall off, but will have some rotational freedom, so you have to monitor the orientation in the viewfinder to keep the images horizontally aligned. It's one more thing to keep track of while shooting, but I found it worked. Perhaps if you wrap some teflon tape around the threads there would be more friction and the Steritar would not get nudged out of the horizontal orientation. (This is an advantage of the RAF adapter - there are screws to adjust horizontal alignment.)

Two more tips from my experience:

1. The internal threads of the Steritar are silver, which causes internal reflections. I blackened them with a fine black Sharpie and got better results. Matte black paint would be even better but I did not want to take the chance of dripping it onto the prisms!

2. The two half-images from the Steritar show considerable horizontal keystoning. Fortunately, Stereo Photo Maker Pro (I assume you use this program) corrects for it automatically. This is also a good reason to use a 35mm lens rather than a 50mm lens with the Steritar (it's officially designed for a 45mm). The 35 accommodates 100% of the field of view of the Steritar, and then Stereo Photo Maker Pro crops out the thin black trapezoidal surround, whereas a 50mm crops out a lot more of the images.

Good luck with it!

The additional distance added by a pair of step-up/down rings won't affect the focus - they come between the lens and the Steritar prisms, leaving the distance between the lens and the camera body unchanged. They will, however, shrink the images a bit, leaving more of the trapezoidal vignette if you use a 35mm. With a 50mm, which ordinarily crops the Steritar image a bit, they might even help. I suspect that pushing the prisms out might also lose a bit of contrast, but probably not noticeably.

No point in using a 28mm -- that would only result in a thicker trapezoidal vignette.

I got very usable results from the Steritar + Biogon. They are the images in this gallery that were taken from a kayak: https://www.stevepinker.com/Stereo/Cape-Cod-Stereo-II/

(you can verify which ones used the Steritar from the metadata, which I entered manually). Examples below. As you see, you'll have to live with some residual vignetting, even after Stereo Photo Maker Pro un-keystones them and crops out most of the black surround. And there's a noticeable loss of contrast and resolution compared to the naked lens, though the Leica M11 sensor and some photoshop adjustments deal well with the losses.

If you're looking for other Leica stereo options I recommend the Zeiss Stereotar dual-lens unit, which comes with a Steritar-like prism attachment, and often with close-up lenses. It's a similar idea to Leica's own Stemar, but the Stemar is very hard to find and very expensive. The Stereotar is mechanically and aesthetically beautiful, and readily available on eBay, often sold with prism, close-up lenses, an ingenious viewfinder, all in a leather-and-suede box. The optical quality is considerably better than a Steritar because the light is not as steeply angled as it hits the sensor.  Unlike the Stemar, it's not properly rangefinder-coupled for a Leica, so focus has to be checked using Live View or an EVF.

And the biggest challenge is finiding an adapter: A Contax-RF-EXTERNAL-Mount-to-Leica-M adapter. Most of the Contax-RF-to-Leica adapters on eBay are for the INTERNAL mount and won't work without surgically modifying the adapter. The perfect adapter is made in small quantities by Amedeo and sold (intermittently) by CameraQuest -- they had them in stock a couple of weeks ago, and I snagged one. A third alternative is to ask RAFCamera to custom-make one, which I did . Rafeal was agreeable, but it was hard to fit long-distance from Belarus, and the first one he shipped was too tight, and the second too loose. Still, that's three options, and the results (I think) are worth it -- it's a gorgeous piece of equipment, and takes superb stereo photos.

No, it's just a ring. The adapters for old Contax RF lenses with an internal mount allow this, but the Stereotar uses the external mount. The Stereotar does have an ingenious coupling gear and round window that fits over the Contax rangefinder window, but it doesn't align with a Leica M. And the equally ingenious Contameter external viewfinder that's part of the full Stereotar kit works with the Stereo Proxar lenses to allow close focusing by moving the camera toward or away from the subject until the images superimpose. But that's only for closeups.

Since stereo photographers are advised to maximize depth of field, the other option is to close down to f/16 or f/22 and set the distance scale to the hyperfocal distance -- pretty much everything you'd want to include in a stereo shot will be be in focus. It works better with late-model digital Leicas, since the high ISO settings needed for the small aperture have little noise. More challenging with film except in sunny conditions.