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Post by barbarian on Jul 24, 2015 11:47:49 GMT -5
Thank you, retina, for the website. Our middle school photo club does some 3d, and it's clumsy in GIMP. I think the program you linked will be much easier to use. Ironically, I just got back from a trip in which I was doing cloud 3d shots while Mrs. Barbarian was driving. I'll get those fixed up and posted. I guess it would be easy enough doing both cross-eye and regular examples. Here's one I did earlier:  |
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Post by barbarian on Jul 24, 2015 11:52:01 GMT -5
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Post by philbirch on Jul 25, 2015 14:00:34 GMT -5
The second shot is exactly the type of shot that benefits from 3d. Lovely.
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Post by belgiumreporter on Jul 26, 2015 8:38:47 GMT -5
Also I have a curious piece of Pentagon gear, it was sold as a bellows sub rack, two rails with an adaptor to which the bellows or camera was screwed. Bit it has no rack, and is therefore of limited use as a sub rack. But then I noticed the length equals the average eye to eye distance, and after a bit of research found that Dresden had intended it as a way of making stereo shots as well. You placed it sideways on the tripod, and moved the camera to the left end, took a shot, and then moved the camera to the right to take the second shot. Personally I do not like to do shots one after the other, and used two LTL Practicas with a dual release. It minimises the risk of foliage being moved by the breeze etc. Stephen. Stephen , this is the tool you mentionned it was called the "einstell schlitte für näh aufname" if i remember correctly. I bought it some 40 years ago (how time flies) when i as a young man spend some time in eastern Germany. It is one of the few eastern German photographic tools i kept all this time as it is so usefull, both for macro and stereo work.A friend of mine made callibrated templates to fit on the guide rails to easely make close up stereo shots, as you may know the stereo base distances varies depending on the camera to subject distance.Still there are a lot of pitfalls (specially when using other than standard focal lenghts) because of stereo parallax occuring near or far.    All these anaglyphs where made with a 100mm fogal lenght and a stereo base of some 3cm  This one was made with a stereo base of 7cm, the stereo effect is more dramatic, but the parallax in the background becomes very prominent, to avoid this the camera would need to be put at a calculated angle to compensate for the parallax |
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Post by Rachel on Jul 26, 2015 17:45:20 GMT -5
BR, what do you mean about the parallax in the background? I'm not sure what I'm looking for.
Regarding the non-anaglyph stereo, I find the cross-eyed form easier to view with the naked eye.
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Post by philbirch on Jul 27, 2015 19:24:39 GMT -5
BR, what do you mean about the parallax in the background? I'm not sure what I'm looking for. Regarding the non-anaglyph stereo, I find the cross-eyed form easier to view with the naked eye. I think he means; when a standard lens i.e a 50mm lens is used with, say a 3inch stereo base, the images will have a slight overlap but at least 90% of it would be visible as 3d, now if a 135mm lens is used with the same stereo base, there could be a bigger overlap as the field of view is narrower, so perhaps only 35% (or less) of the image would be visible as 3d. Conversely if a wide angle lens is used there would be minimal 3d effect. When using wide lenses I use a base of about 2 feet. I'm not sure that parrallax is the correct word, but it will suffice iin this case. The figures quoted are estimations but should be enough for you to understand the gist of what I'm saying. I looked at the photos with my 3d glasses on and they are good, the 3d effect isnt very pronounced on the Pentaxes. Perhaps a short base was used, I like to use a slightly longer one than the adaptor shown would give. When taking 3d images, I like to frame them the same. I decide what element of the image should be the 'focus' and take the picture, when I move the camera I (try to) put the object of focus in precisely the same part of the frame. I tidy up the images afterwards. Using this method, the base isn't flat but curved - effectively. Base: the distance between the eyes or camera lens. |
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Post by belgiumreporter on Jul 28, 2015 2:17:36 GMT -5
BR, what do you mean about the parallax in the background? I'm not sure what I'm looking for. Regarding the non-anaglyph stereo, I find the cross-eyed form easier to view with the naked eye. I think he means; when a standard lens i.e a 50mm lens is used with, say a 3inch stereo base, the images will have a slight overlap but at least 90% of it would be visible as 3d, now if a 135mm lens is used with the same stereo base, there could be a bigger overlap as the field of view is narrower, so perhaps only 35% (or less) of the image would be visible as 3d. Conversely if a wide angle lens is used there would be minimal 3d effect. When using wide lenses I use a base of about 2 feet. . I'm not sure that parrallax is the correct word, but it will suffice iin this case. The figures quoted are estimations but should be enough for you to understand the gist of what I'm saying. I looked at the photos with my 3d glasses on and they are good, the 3d effect isnt very pronounced on the Pentaxes. Perhaps a short base was used, I like to use a slightly longer one than the adaptor shown would give. When taking 3d images, I like to frame them the same. I decide what element of the image should be the 'focus' and take the picture, when I move the camera I (try to) put the object of focus in precisely the same part of the frame. I tidy up the images afterwards. Using this method, the base isn't flat but curved - effectively. Base: the distance between the eyes or camera lens. Thanks Phil for explaining this issue, my knowledge of English falls a bit short to explain in detail what exactly happens when making steereo pairs with diffrent focal lenghts and diffrent recording distances. I think you're explenation pretty much nailed it.It has been a long time ago since i've gotten invooved in 3D photography and i need to refresh my memory on the subject. The digital revolution did reshuffle the deck though... |
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Post by Rachel on Jul 28, 2015 4:45:33 GMT -5
Thanks both of you for the explanation. I think I get it  I do find 3D photography very interesting although I've not done any for years and that was using a beam splitter with slide film. Somewhere I have a Stereo Realist camera but I've never put any film through it. I also have the excellent Stereo Realist Manual + viewer with all those interesting stereo pictures to view. |
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Post by philbirch on Jul 28, 2015 15:26:06 GMT -5
I bought a Russian stereo attachment along with its slide viewer. I must give it a go. It will work on digital too!
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Post by belgiumreporter on Jul 31, 2015 4:03:04 GMT -5
Here's a solution that may help if you don't want to mess around with one camera to make stereo pairs. Just add a double wire release and you're good to go :-)  |
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Post by Rachel on Jul 31, 2015 7:25:53 GMT -5
Budget stereo? |
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Stephen
Lifetime Member
Still collecting.......
Posts: 2,718
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Post by Stephen on Aug 2, 2015 8:43:42 GMT -5
The point about the background is that the two views must actually line-up with each other on the farthest item, be it an object or infinity etc.
Most cameras and set ups are set to parallel views and do not adjust for closer objects in the background. A correct set up would be to have the cameras pointing at the farthest point of interest in the shots, ensuring an exact overlap at that point. If this is done then the depth of closer objects are more correctly shown.
In practice a lot of 3d id barely more than "Two Plane", the effect that is used in the so called conversion of flat Cinema films to "3D" . Most of the two colour types give the shallow two plane look, whilst the double image in colour, via a viewer or cross eyed observation give a much greater depth.
So the rule for two cameras is to set to at least parallel or slightly inwards, or to check the view to ensure that the farthest items overlap.
The Leica adaptor and the Russian one are set to a degree or so inwards I believe. Some other can adjust on of the prisms to get the background items overlapping.
Stephen.
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Stephen
Lifetime Member
Still collecting.......
Posts: 2,718
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Post by Stephen on Aug 2, 2015 8:49:21 GMT -5
What Victorian photographers used was two cameras, with a wooden rod running from front to back on each camera, set parallel to the lens and film, the wooden rod having two nails fitted to each end vertically, that act as a sight guide to exactly where the camera is pointed. The view would be set on one camera, and the sight used to find a recognisable point, and then the other camera would be lined up on the same point, Viola! the perfect 3d setup for perspective.
Stephen.
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Post by philbirch on Aug 2, 2015 16:27:13 GMT -5
This is what I strive to do with my 'curved' base.
I think the 3d effect is better.
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