Macro-photography

Different strokes. I've never been able to do cross-eyed but have historically had no trouble at all with
parallel (wall-eyed) pairs. Little more difficult these days but that's age related.

I've been into stereo photography for probably 40 - 50 years ... I still have an extensive camera and projector collection .... and my recollection (which admittedly might be faulty at my age) is that years ago parallel views were used almost exclusively for free viewing. Probably why I have such difficulty now with cross-eyed viewing. The autostereogram pictures are usually (always?) parallel as far as I know.

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The 15° included angle between the tubes of typical ‘Greenough’ stereo microscope works very well.

The brain seems to ‘understand’ that the eye-lines converge when looking very close.

MichaelG.

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This is very low resolution, but I think it demonstrates the point

Edited By Michael Gilligan on 25/04/2022 08:11:32

Thanks for that, Michael. It's a different concept to what I had in mind (mine was to point the lenses directly at each other with a prisms/mirrors to turn the light 90 deg.) but yours looks eminently more do-able. In fact I have a spare lens plate and, probably, a spare set of sensors so I could make up an extra lens board pivoted in the middle and experiment.

Sounds like fun, thanks again!

When I was a kid, I was given a stereo camera with some glass plates of toboggons on the Cresta Run. The camera was made of bakelite with a detachable front which housed the shutters and sliding apertures which were just a set of paired holes. With the front off, the body could be used as a viewer, using the single element meniscus taking lenses. The glass plates were about 4" x 1 1/4" with a pair of 1 1/4" images. The images were monochrome reversal, not negatives. I think the camera was German, and often wonder if it would be valuble now if it had not been eventually destroyed by me.

If you contact the knowledgeable folk at Photo-3D group and describe the camera, they may be able to identify it and possibly give you an estimate of its value (if you still had it).

Hi old mart, your camera may have had some value, but the glass slides may have been worth more as they probably could have been viewed by other means, the photos on them would also make a difference.

Regards Nick.

Michael, do the lens axes intersect at the focus or is there a slight gap between them at that plane?

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They intersect, Peter

… I will find you a diagram

MichaelG.

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Edit: __ This is a useful note by LMscope :

https://www.lmscope.com/en/Stereomikroskope_in_der_Fotodokumendation_en.html

but they are specifically discussing ‘single channel’ imaging.

If you are making stereo pairs, the cameras should each see exactly what the eye would [so you are relying upon depth-of-field]. 

Edited By Michael Gilligan on 27/04/2022 05:34:49

Here’s an example of some vintage Greenough hardware: **LINK**

https://www.micromagus.net/microscopes/zeiss_greenough.html

But a pair of Pi cameras with long-ish lenses should do the job without any microscope optics.

MichaelG.

Thanks, Michael. I was just looking into the geometry I'd need when modifying my camera. Then I realised that it doesn't really matter anyway since I have independent control over the object distance and the focussing of the lenses. So I can set up anything I want at the picture-taking stage.

(If that makes sense).

Hi, the Canon 400D camera that I bought the other day, came this morning, so after checking it out I set it up with my original one and gave it ago for a stereo pair on my No. 4 Denbigh Fly-press and the first attempt looks good through my Owl VR stereoscope, works OK for me with the parallel free view as well. Top photo for parallel viewing and bottom for cross viewing.

Regards Nick.

P.S. I've got two different pictures this time Sam. 

Edited By Nicholas Farr on 27/04/2022 21:43:48

So I see Nick ... with eyes crossed.

Thanks for your input and others for a most entertaining thread.

Cheers,

Sam

Parallel free-viewing works nicely for me, Nick

MichaelG.

A couple of years ago (22nd May 2020), soon after Raphael’s thread became piggybacked with 3D images, I experimented with views from my skeleton clock CAD files.

For reference, look towards the end of … **LINK**

I noted then that a five-degree rotation of the CAD image seemed to work.

Before my enthusiasm faded, I messed about with a pair of plastic-coated paperclips that I could rotate five degrees. Photographed through a 100mm Macro on my Canon 300D here is the result for parallel and crossed viewing.

It’s quite clear that I could also have skewed the clips themselves to increase the 3D effect. Instead, I gave preference to depth of field.

Clearly, although only one camera is necessary, this (table-top) method is only suitable for static objects. I certainly look forward to your two-camera results Nick. My thoughts about synchronised shutters were more to do with if and when you turn your attention to animated objects.

Cheers,

Sam

Hi MichaelG and Sam, it's good to know you can satisfactorily view my Fly-press pair. I like your paper clip idea Sam, but at first I was confused as to which one was the parallel view one, as they both appeared to be in 3D although with them being opposite, upon closer inspection though, I could see that the left hand end of the blue one in the bottom view, was trying to look as if it was pushed slightly backwards but is actually obscuring part of the foldback going to the right hand end, near the bottom of the left hand end, which of course means this must be the cross view one. So apart from them being opposites, that's such a subtle difference.

Regards Nick.

Edited By Nicholas Farr on 28/04/2022 12:45:51

Spot on, Nick.

Although I tried to stay with the current (unwritten) convention seemingly adopted earlier, i.e., parallel at the top and crossed underneath, I was rather mischievous in withholding their identities.

Not knowing if those with a ‘predilection’ for parallel viewing can see in the blink of an eye, which is which, it suggests to me that crossed viewing has a slight edge.

Did you notice the longitudinal split in the plastic? It’s just under the lower loop of the red clip. Beside some dust, there's also a whisker ... top right on the red clip.

Cheers,

Sam

Hi Sam, no I didn't spot the split or the whisker, but there again I wasn't looking for anything like them. Having another look, I see the split but I had to use my stereoscope to see the whisker and it shows up better in the cross view one.

Regards Nick.

Nick said ... it shows up better in the cross view one.

That's curious Nick. I might presume an eye imbalance, which is very likely with my faltering right eye.

Cheers,

Sam

Hi, a few weeks ago I bought a second hand Canon IXUS170 compact camera off ebay for a very nice price. This together could then be used on my twin camera bracket that I finished yesterday.

All that was needed was something to try them out on, so I got a bit adventurous which would really push the limits, that something had unpredictable movement within its self if left not touched. I wasn't sure if it was at all possible but the result on a first attempt were very much what I had hoped for, now I'm not saying it was perfect and I think the angle between the two cameras was slightly too much, but the stereo pair works well for myself, both in free view and with my stereoscope. The top pair are the parallel view and the bottom pair are cross view.

Hope they work for anyone who likes stereoscopic pictures.

Regards Nick.

Edited By Nicholas Farr on 16/06/2022 12:19:01

Hi Nick,

I for one am impressed with your latest work and your determination to pursue even better results. For me, the corona(?) movement is blurry as expected and would be - should I say - impossible to capture without synchronised exposures.

Keep up the good work.

Sam