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Mineral PhotographyCrossed eye steropictures

14th Dec 2019 12:46 UTCVolker Betz Expert

im am experimentig with crossed eye steropictures. This are taken with lens focus stacking with some slight changes in the y-axis and a 5 ° adjustment in the camea axis.

I can se the stereo-effect with crossed eyes quite well and wold like to know that ist works for other viewers aslo. I see it best in full viw from 80 cm distance from screen.

14th Dec 2019 13:08 UTCAlfredo Petrov Manager

Works perfectly for me, Volker. Great shot, very sharp stereo image!

14th Dec 2019 14:46 UTCKevin Conroy Manager

Hi Volker, I can see stereo, but I'm seeing it in negative.   Should the left image be on the right, and the right on the left?

14th Dec 2019 14:51 UTCJolyon Ralph Founder

Working fine, in positive, for me. On phone 

14th Dec 2019 15:21 UTCThomas Lühr Expert

Worked great for me (the very first time for me at all). Used my phone in a distance of about 30cm. I saw the specimen 3 times with the middle in 3D.

14th Dec 2019 14:55 UTCKevin Conroy Manager


Maybe it's just my old eyes!  I've added a photo with the images reversed.  Please let me know which looks right for you.

14th Dec 2019 22:34 UTCLuca Baralis Expert

This couple is better for me.
Impressive 3D effect!

18th Dec 2019 10:17 UTCJolyon Ralph Founder

Yes I agree, this is the better way to see the stereo effect.

18th Dec 2019 13:54 UTCNiels Brouwer

I think it depends on multiple factors which version works best. It takes me far more effort to get the effect to work with this one, but that might be because I'm so used to the cross-eyed version. I think the monitor size has a big influence too: it's easier to cross your eyes slightly further for the effect to work with larger images, whereas you can't stare further into the distance than infinity. So this version only works when it's small enough, whereas the cross-eyed one can be lot larger and more detailed.

14th Dec 2019 16:41 UTCRichard Gibson

They both work for me, but like some, the original is negative for me while Kevin's is positive. Probably just variations in eyes... 

14th Dec 2019 16:50 UTCDr. Paul Bordovsky

Looks great, Volker.  Your image is the positive to my eyes.

14th Dec 2019 17:25 UTCGregg Little

Kevin and Richard;
I can get both a negative and a positive 3-D image depending on which way you let your pupils "drift".  Diverging pupils, like viewing in the old stereopticans or viewing airphoto stereo pairs gave me a negative 3-D image in Volker's photo pair.  Doing the cross-eyed technique gave the positive image in his photos.  Kevin, in your reversed image presentation the divergent technique worked just as well and gave the positive image, by diverging my pupils.

Interestingly, this is the first time I have done both techniques on the same photo and one difference jumped out at me.  By using the diverging technique, the image appeared much larger and clearer as the crystal details "jumped" out more.  The problem some people might have in getting the diverging pupil position is that it takes practice ... or a stereoptican device.

14th Dec 2019 17:28 UTCGregg Little

It would also be nice to know what we are looking at (mineral and location?).

14th Dec 2019 17:33 UTCKevin Hean

I battle a bit to pull the centre image out of the first shot, but the Kevin's reversed image is perfect.

14th Dec 2019 18:30 UTCKevin Conroy Manager

Volker's photography is superb, and I REALLY enjoy the ability to see specimens in 3-D. 

Kevin, I think you're having less trouble with my image because when I reversed the photos I also (inadvertently) positioned the specimens just a little closer together.  This happened because I cropped the photos a bit when I reversed them.

14th Dec 2019 19:50 UTCJohannes Swarts

Really cool!  The image really pops out when you "see it".

The second image worked better for me.



14th Dec 2019 21:16 UTCRalph Bottrill Manager

The first works better for me but they both really strain my eyes and would rather look at normal pictures.

14th Dec 2019 22:29 UTCKeith Compton Manager

Volker's looks best.
Terrific image.

Perhaps Volker, you should create an article in easy to understand steps showing how to create such images.

Great work. Hope to see more in future.

I could also see Kevin's stereo too, but as indicated above it does give a negative image - still cool though. You surprised me Kevin, as my initial thought was that it wouldn't have worked at all.

Ralph - you might be a bit too close if straining your eyes. Try moving further away. If that doesn't work, then add beer or wine and that should help to ease the strain !! ((-:)).

14th Dec 2019 23:33 UTCPaul Brandes Manager

I can see it great in 3D, but not for more than 2-3 seconds as it really hurts my eyes.
Nothing wrong with either photo, just the way I'm programmed. ;-)

14th Dec 2019 23:54 UTCKelly Nash Expert

Ditto. In my case, I have some nerve damage in the muscles of one eye, and just can't make it work even briefly without some extreme effort.

15th Dec 2019 01:37 UTCKevin Conroy Manager

Looking at these image pairs without a stereoscope is definitely taxing on the eyes when you're first introduced to this method.   After nearly 40 years of doing this it's not an issue for me.   Experience also told me that some folks would see the original photo pair in negative, but in positive if the order of the pair was reversed (and vice versa for the pair that I made).

If the stereo images become popular on mindat you may want to buy a stereoscope to view them (if it strains your eyes, and you like looking at them of course).   A quick search found the following, but I'm sure that there are more choices available: 

15th Dec 2019 02:02 UTCKeith Compton Manager

The Mineral Record gave out a stereoscope back in 1987. .. [Mineralogical Record 18(6) : November-December 1987]. I tried it out but that didn't work, so it may just have to be viewed  cross eyed.

15th Dec 2019 02:27 UTCFrank K. Mazdab Manager

I have no trouble viewing these... Volker's as a negative image and Kevin's as a positive image.  Pavel Martynov also has a set of several stereoscopic pairs he featured in an article:

His images, however, my eyes can't seem to bring into 3D view for some reason (except for the "test" image).  Perhaps it's a spacing issue specific to my eyes relative to how the pairs were taken, or the dark line between the images, or maybe the amount of detail in the samples just prevents my gaze from defocusing? I don't know...

15th Dec 2019 02:42 UTCKevin Conroy Manager

Frank, you're probably having trouble with Pavel's pairs because they're a bit too large for your eyes.   You should be able to see them if you reduce the zoom of your display.   I don't know how this works for other devices/browsers, but on a PC in Chrome there are 3 dots in the upper right corner of the screen.   Click them, and then you can use the minus button until the images can come into stereo for you (around 50% should work).

15th Dec 2019 03:16 UTCKevin Conroy Manager

I just checked the article on my phone, and the stereo pairs are viewable as is.  They're small enough (on my cheap phone) that it wasn't a problem.

15th Dec 2019 03:19 UTCFrank K. Mazdab Manager

Thanks Kevin... that did work, but unfortunately all the images were negative. So while they were 3D, the spectacular crystals that should have been perched on matrix were buried within deep vugs instead. I may have to do what you did here and reverse the images.

20th Dec 2019 15:25 UTCVolker Betz Expert

Hello Kevin,
meanwhile I know what happened. There are two ways to view stereo (3D ) pictures. The conventional way is parallel view.Typical it is viewed with a stereoskope ( enlarging the picture with a lens) . This works for most people and the left eye sees the left and the right eye the right picture. The limit of this method is the picture size and picture distance. On a phone the pictures are smaller and so it works for some better.

The second way is the crossed eye view. Here the pictures are moved from right to left and vice versa. The eyes are crossed and the pictures can be bigger. Picture distance is not so critical. Unforunately the crossed eye view needs somtimes training  and also can distract the eyes. There can be found some guides to train eyes and also pictures to thest the eye in the  internet. Above a new test picture with a less FOV (6 mm).   I will continue to optimize parameters to make such pictures.


21st Dec 2019 17:20 UTCGregg Little

Greetings Volker; 
I can with ease switch between the two viewing methods (parallel and crossed) but viewing it the wrong way (in the negative image) is detracting. Might I suggest that, to keep the interest for those who have trouble with one method or the other, posting or publishing two sets of stereo pair photos,  one for the crossed crowd and one for the parallel crowd.

15th Dec 2019 06:57 UTCDon Windeler

For me Kevin's works much better, but that's because I'd trained myself to do the non-crossed approach.  Basically I had been using stereoscopes in grad school and someone told me "You can do it without them" -- at which point I just had to figure it out.  (Made me much better at those "Magic Eye" posters in the 90's, too.)

Basically I try to focus on something farther away and then just let my eyes drift.  It actually doesn't strain my eyes at all once I lock in, though that is probably a function of viewing distance.

I can force the crossed-eye approach, but it is much more straining to me.  The resolution is also slightly less, as you're dealing with a marginally longer viewing distance with each eye.

Good fun, though!


p.s. I'm viewing it on a laptop from about 50 cm distance (30 cm wide screen).

15th Dec 2019 09:50 UTCAdolf Cortel

Hi Volker,
In the desktop computer(about 40 cm in diagonal) I can see the 3D image very well at 60 cm.  In this situation the only way of seeing a normal convex 3D image is by crossing eyes. Since the distance between the two pictures in the screen is similar o bigger than the distance beetwen the eyes  you cannot see it by looking far beyond the screen. Those watching it in a small screen, as in the mobile phone, can see both convex or concave 3D images depending on the point they focus the eyes.
It would be nice having more stereoimages uploaded in mindad. However, the ordering left-right of the pair should be different for computer of phone users (unless the phone users agree to cross the ayes!)

15th Dec 2019 13:49 UTCVolker Betz Expert

thank you all for the comments. It looks like that there are three groups of viewers:
one group can see the original picture positive and the reversed from Kevin negative.
The other group sees the reversed pair positive and the original negative and a third group can see both positive. Myself sees the original positive and the other negative. If I use a mirror stereoscope I can see the the reversed picture of Kevin also positive.

Some mention eye distress, this is a point to dislike stereo pairs, but can sometimes improved by training and also possibly by changing the parameters how the pictures are made.

Attached is a new picture made with different parameters, so again ma question: How works this picture ?.


16th Dec 2019 13:28 UTCGerhard Niklasch Expert

Both pictures work fine for me regardless of arrangement - but then I've been dabbling in stereo photography for more than three decades and can fuse any reasonably well-aligned pair in an instant, whether crossed-eyes or parallel.

Crossed-eye pairs like Volker's and Pavel's, as the name implies, need to be viewed with eyes crossed to get the correct depth effect (converging to a point between the screen and your nose: a helpful trick is to put a finger there and look at it and wiggle it until the partial images behind it begin to blend, then let the eyes re-focus on the background images while keeping them converging). Parallel pairs like Kevin's version need to be viewed with (more or less) parallel-looking eyes (converging to a distant point behind the screen but focusing on the screen). Persuading the brain to set the eyes to a focus distance different from the convergence distance takes a little effort either way, but gets easier with practice, as long as one eye isn't much weaker than the other.

For use without a mirror stereoscope, crossed-eye pairs are more versatile because they'll still work when each picture (and thus the separation between corresponding points on the two pictures) is wider than the viewer's eye-to-eye distance. A too widely spaced parallel pair, on the other hand, cannot be fused at all by most people without optical aids, since the eyes would need to diverge.

When preparing such pairs: The image scale needs to agree within a fraction of a percent; corresponding pixels in the L and R image should be at the same vertical coordinate to within one pixel; any relative rotation needs to be corrected to within better than half a degree. All of which are easier to achieve with some kind of mechanical stage, but careful postprocessing can give decent results even from hand-held shots. And the lighting had best match exactly: Moving the subject sideways whilst keeping lights and camera fixed may not yield the best results; better move the camera and its optics only, or else move the lights and the subject together whilst keeping the camera position fixed.

15th Dec 2019 19:39 UTCAdolf Cortel

The needles can be seen very well. The key is the convergence of the eyes. To see the right 3D image the eyes must converge in front of the plane of the image. I have had to display the full image in the screen to appreciate all the details.
Using an stereoscope you will see the opposite (concave) image since the converging point is in the back of the plane. 

16th Dec 2019 17:02 UTCAdolf Cortel

Hi Volker,
I've spent a bit more of time with your images. In the first one you uploaded (augite) there is something worth to be mentioned: when you see the 3D image some the faces of the crystals have a particular gloss which is not seen in the individual pictures. This gives a sensation similar to the one you have when observing with bare eyes or with a bino. This gloss arises from the difference in the light reflected by the crystal faces in both pictures. 

16th Dec 2019 23:20 UTCDouglas Merson Expert

While I see both of Volker's as positive, it is bit difficult using a curved monitor. I find my positioning it more critical than with a flat monitor.

17th Dec 2019 16:51 UTCNiels Brouwer

I've been using this three-dimensional imaging technique quite a lot as well. I'm amazed every single time by how incredibly detailed and lifelike these stereo images are.

I hadn't heard of the divergent technique as Kevin and Gregg describe, only the cross-eyed technique. I've found that for people who are not yet as used to looking at it with crossed eyes, the small white circles above it help to find the right amount of overlap.

17th Dec 2019 20:00 UTCVolker Betz Expert


Hello Niels, nice pictures.
Here is a rock crystal that I photographed as an experiment. 

My last stero-pictures are 25 years back at analog times.  Meanwhile  have updated my knowledge litte bit. Crossed eye steropictures seem to me a good tool to make specific details visible.  Curently I am exploring the parameters  and a good workflow.

I left in the past stereo pictures because the need of optical tools and the limitation in picture size.  Unfortunately viewing crossed eye  stereo-pictures do not work for all. Some need training as discussed in the net. At least a interesting object to study.

17th Dec 2019 22:16 UTCJerry Cone Expert

Niels, I've never been able to see what everyone else is, but with your dots above the specimens  it's a cinch! Thank you.


18th Dec 2019 09:20 UTCGerhard Niklasch Expert


Inclusions in transparent crystals definitely benefit from being viewed in 3D.

There's a bit of a brightness gradient in the background from left to right in this image - it's not yet distracting for me, but it should not be any stronger. Having a brightness jump and thus a visible edge in the middle separating the two half-images (as in the Augite picture at the start of this thread) may even help with fusing them.

18th Dec 2019 14:00 UTCNiels Brouwer

Jerry, great to hear that! Several others had the same experience as you did, once you get more used to viewing these you'll probably find you no longer require those dots, but the first few times they can help a lot.

Volker, you're right it works an absolute treat with transparent minerals like that quartz. It seems the transparency is enhanced when seen in 3D, because of the added depth.

18th Dec 2019 20:15 UTCGregg Little

Volker; I found your quartz stereo pair the hardest to keep in focus (diverging or converging focal points) probably due to the angle between the pairs.  Notice the termination faces, particularly the Z-face is significantly different in shape due to the angle. I can force the images together but the image tends to dance as my mind tries to merge them. Your very first photo of the augite is very easy to merge, as most found.

17th Dec 2019 20:52 UTCPaul Brandes Manager

Love the photos you're all posting and I can get a 3D image, but boy, after a few seconds I have to stop because as Kelly mentioned earlier, it is very taxing on the eyes.

18th Dec 2019 10:19 UTCJolyon Ralph Founder

Of course when mindat is connected to a 3D monitor such as an LG 3D TV the results are even better. 

18th Dec 2019 14:03 UTCNiels Brouwer

I'd love to get one of those monitors at some point. I'm also curious where Facebook will take their 3D photo feature: it's still somewhat limited right now, and I haven't found a good way to properly convert these stereo images to their format, but I think it has a lot of potential.

18th Dec 2019 21:38 UTCNiels Brouwer

Here's another one I really enjoyed photographing during the recent Munich show, it really emphasises the clarity and play of light in that fluorite.

From Mina La Viesca, Huergo, Asturias, Spain.

22nd Dec 2019 03:23 UTCJim MGlasson

I have no problem with any of these.  Especially like the fluorite
As a field exploration geologist I have been viewing stereo aerial photos without a stereoscope for years, had to learn to do it because using a stereoscope is harder in the field on steep terrain and have no access to flat areas to lay out the photos.

22nd Dec 2019 16:32 UTCVolker Betz Expert

Hello, I continued experiments.  For me it looks tha making crossed eye 3D pics is easier than viewing. For those wo are not able I found a tutorial:

The above picture (click for viewing) can be best seen on a  monitor (24 ") from a distance of 80 cm and more. It is importenant that the view is always horizontal and not inclined.  Smaller pictures can be seen from closer distance, but theindividual  pixels  may the be visible.
Crossed view pictures have the advantage that the picture size and distance is not so limited in size  as with parallel view.

Viewing on a mobile phone automatical reduces picture size. Here parallel view  may be more easy.


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