Stereoscopic Pairs

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, while on my visit to the MMEE 2022, I tried my stereoscopic photographing technique on a few of the competition exhibits, and I believe they have worked well. It was a practical field test, so to speak, as I had no control of any of the background or the lighting that was available as I didn't wish to use flash. So below are four pairs, each of parallel view and cross view. The parallel views are the top ones of each of the pairs.

I forgot to take note of engine 1, but engine 2 is a USS Monitor Battle Ship Engine by David Roads.

Regards Nick.

[Nicholas FarrParticipant @nicholasfarr14254]

Taken at the Midlands Exhibition 2022

[Michael GilliganParticipant @michaelgilligan61133]

VERY impressive, Nick … Well done, Sir !

The only disturbing oddity for me was that the front forks on the Goldie appear to be spaced much too wide.

Can’t really work-out why, but there it is [free parallel viewing]

MichaelG.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi MichaelG, I don't know much about motorcycles, so can't put up an explanation, but I've compared it to the right-hand photo, and it doesn't look to be out of place, it could just be the angle they were taken at and some effect of the depth of field. It does look quite impressive to me when I view it through my stereoscope, in spite of any miss giving's the pair may have. I thank you for your comments though, which does help to think more about composing shots. I did wait till later in the afternoon when there weren't so many people that I would get in their way of viewing them. I did photograph a Stuart No. 4 engine, but for some reason that didn't work very well, but it was very close to the front of the table, and I could only view it looking down on it a little steeply, but hay-ho, it's all a learning curve, and electronic ink is cheap enough to delete.

Regards Nick.

[Michael GilliganParticipant @michaelgilligan61133]

It will be interesting, Nick, to see whether any other viewers get the same impression as me.

I think its just a perspective effect, making things just a little too impressive [if you see what I mean]

Looking at the images individually, the forks appear wider spaced on the Right Eye image … purely because of the angle of view … and it could be that my dominant right eye exaggerates the effect of that.

Whatever: they are a very successful set of pictures … thanks for sharing them.

MichaelG

[Joseph Noci 1Participant @josephnoci1]

Outstanding! Cross view only…I cannot get parallel view to work at all. Nothing to do with your photo's though – have never been able to! I 'almost' get there using a cardboard sheet with two eye-spaced holes, start close up to the image and slowly pull away – often there is a 'moment' where the view almost pops out, and then its gone!

The cross views work in an instant, everytime, and those are superb.

Something I have not realized in previous views, the resulting image seems to increase in sharpness? In the background of Engine-2 on the left is a small horizontal cylinder engine – the fins of which seems much sharper and hard edge defined than in the photo itself. Likewise the anti-theft cable/wire strung through the models seems to loose the image pixelation. Is that possible?

Great photos!

Joe

[Martin ConnellyParticipant @martinconnelly55370]

I had to reduce the zoom on my monitor to get the spacing less than 62mm (my pupil spacing) to view the 3D image on the screen. At this reduced size there is a loss of detail that would probably return if I printed them off. Otherwise it was interesting to see the 3D image.

Martin C

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, I have had another go at the pair of Stuart Turner No. 4 engine made by J. Wing. I had to crop them quite a lot and needed to space them a little further apart. They will work, but I find a little ghosting at the edges, and what I think the problem is, that I didn't compose the cameras quite parallel enough to the model, and coupled with the steepish vertical view, doesn't allow everything to line up in stereoscopic viewing. I can see the parallel one in free view, but I do have to concentrate on the centre of the view and try to ignore any ghosting each side, but it does work better through my stereoscope. I don't know how successful the cross view is, as these always appear jumbled to me, but they are both shown below, and I realise they are not my best effort.

The parallel one is at the top, and I await everyone's comments on how successful or not, as to whether they work for them.

Regards Nick.

Edited By Nicholas Farr on 17/10/2022 09:40:53

[Frances IoMParticipant @francesiom58905]

normally my eyes click into cross view quite quickly but took a bit to lock onto the above but they did and the detail + crispness of the image were outstandingly excellent but the depth appeared to be very exaggerated.

[Michael GilliganParticipant @michaelgilligan61133]

It works [free viewing parallel] for me, Nick … but I agree it does require some concentration.

You are definitely onto something here: Keep up the good work !

MichaelG.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Martin C, yes, the width of these can make all the difference, and everyone's eyes are not exactly the same distance apart. I have done some that I can see OK, but others can't see even through my stereoscope, just because they are just a little too wide.

Regards Nick.

[Kiwi BlokeParticipant @kiwibloke62605]

I couldn’t get the ‘parallel’ ones to work (usually can…), however, the ‘cross-eyed’ ones work well. However, I’ve now got two computers in front of me and four hands. Is that supposed to happen?

[Sam StonesParticipant @samstones42903]

Nick, I must congratulate you on the rapid progress you have made in such an apparently short space of time. And, what better suited to us Model Engineer enthusiasts than ‘pictures at an exhibition’ (Mussorgsky).

Thank you also for going that extra step by including both stereo pairs.

As a (lucky me) crossed-eyed viewer, but never a BSA owner and with nothing to compare, I have to accept Michael’s comment about the forks.

From my ‘perspective’ there’s little I can add to Joseph and Frances insights.

While crossed pairs (usually) lock in almost instantaneously, I did struggle with your (heavily cropped) pair of the Stuart Turner No. 4 engine. Tracking front to back didn’t work well, but when they did ‘lock’, the sharpness was again, really impressive.

Joseph, I was surprised with your comment about the increase in sharpness. I can see clearly, what you mean. Could it amount to an overlap, a fractional sideways shift, or even a (near) doubling of the pixilation?

A great result!

Sam

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, thanks for all the comments. I've had a good study of the engine 2 and this apparent increase in sharpness in the fins on the engine on the background, and my conclusion is that it is because it's a virtual 3D view, rather than just a flat image, does give it an increased sharpness, but that maybe my own perception of what is happening. The Stuart Turner no. 4 engine is a challenge, but I can see it easier now in free viewing, but find the viewing has to be parallel, both vertical and horizontally to my eyes for the best effect, but I can't see the whole engine in real focus at the same time, i.e. I can get the top half in focus, but the base is a little ghostly, and have to then kind of concentrate on the base to get that focused properly, but the top half then seems to be in the upper part of my near-peripheral vision but am now able to switch between looking at the top and base in focus, almost instantly. Quite pleased with that as I thought that both the un-cropped photos were a total failure to begin with.

I meant to also say that I think the wooden cladding on the engine 2, also seem to have an increase in sharpness in stereoscopic viewing.

Regards Nick.

P.S. I will just add that these photos were taken on a point and shoot kind of thing, as I didn't dwell to much as not to be in the way of others, and it was getting close to the show closing time.

Edited By Nicholas Farr on 18/10/2022 10:57:04

[Michael GilliganParticipant @michaelgilligan61133]

What really astonishes me, Nick … is how very effective these images are, for such small files.

We tend to be obsessed with resolution and image ‘quality’

But I have just copied your parallel pair of the Goldie, so that I can perhaps study the geometry

… the jpeg file for the pair is only 1024×371 pixels and 103kB

… but it works beautifully.

The eye and brain must be quietly doing a lot of work to achieve this !

MichaelG.

[roy entwistleParticipant @royentwistle24699]

I cannot get any pair to line up. I could before I had cataracts removed from both eyes.

Roy

[Robert HoltonParticipant @robertholton69149]

The Gold Star looks great and I can't see anything wrong with the front forks. I am a motorcycle enthusiast and have restored quite a few. I have a 1968 T120 Bonneville these days.

Rob

[Michael GilliganParticipant @michaelgilligan61133]

This is only rough, and might not convince anyone of anything … but I offer it for consideration:

.

.

As printed and drawn-upon, the horizontal distance from the bar-end to the [rider’s right] fork leg is approximately

15mm on the left image and 17mm on the right image

I think that’s why [given my dominant right eye] I am seeing the forks and bars as excessively wide in 3D

… it’s presumably geometrically correct, but that’s very strong perspective

Please feel free to offer any alternative explanation.

MichaelG.

[Sam StonesParticipant @samstones42903]

Following on from Joseph’s observations Nick, the improved sharpness appears to relate directly to (left/right) staircase divergence.

Likewise, this ‘Focus Synergism’ improves the DoF.

How fascinating.

Sam

[Nicholas FarrParticipant @nicholasfarr14254]

Posted by Michael Gilligan on 18/10/2022 11:09:04:

What really astonishes me, Nick … is how very effective these images are, for such small files.

We tend to be obsessed with resolution and image ‘quality’

But I have just copied your parallel pair of the Goldie, so that I can perhaps study the geometry

… the jpeg file for the pair is only 1024×371 pixels and 103kB

… but it works beautifully.

The eye and brain must be quietly doing a lot of work to achieve this !

MichaelG.

Hi MichaelG, I guess the eye and brain do a lot more work than we realise. The forum software obviously reduces the size of the pairs as the one I produced for the parallel pair is 1602 x 581 @ 254 dpi and its size is 219 KB, size on disc 220 KB. This is about the maximum size that my phone will allow an adjustment on a sliding scale on screen, any bigger and the image will only reduce down from full screen to a minimum size. I have found when printing them out, that if the size is wider than a certain size, I might be able to see them, but other people can't, even when viewed through a stereoscope, and even when my daughter can see some wide ones, my son-in-law can't, and he can't always see them at full screen. Neither of those two can free view and can only use a stereoscope. I'm sure one's brain must make up some details that it thinks you should see, maybe from what it learns from everyday life.

Regards Nick.

[Nicholas FarrParticipant @nicholasfarr14254]

Posted by Sam Stones on 18/10/2022 21:06:18:

Following on from Joseph’s observations Nick, the improved sharpness appears to relate directly to (left/right) staircase divergence.

Likewise, this ‘Focus Synergism’ improves the DoF.

How fascinating.

Sam

Hi Sam, thanks for your thoughts on that and I think I understand what you are saying, and yes, the whole concept is fascinating to me.

Regards Nick.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Nicholas Farr on 19/10/2022 08:56:24:
[…]

I have found when printing them out, that if the size is wider than a certain size, I might be able to see them, but other people can't, even when viewed through a stereoscope, and even when my daughter can see some wide ones, my son-in-law can't, and he can't always see them at full screen. Neither of those two can free view

.

Just picking-up on that point, Nick [ ‘though I don’t want to drift the discussion too far]

I use the 9.7” iPad for parallel free viewing these, and find the pinch-zoom feature very helpful

Inter-ocular distance is critical and the 3D just ‘snaps in’ when the image separation is perfectly matched.

MichaelG.

.

Note: I underlined parallel because in that use-case the gaze is parallel.

I would hypothesise that cross-eyed viewing [which I cannot manage] is less sensitive to mismatches, because the gaze is converging and the eye/brain system is more active.

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