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3D shots using fairly normal SLR camera

take 2 rapid shots with the help of fast shutter speed and accelerometer
  [vote for,

This would be limited to slower subjects, but if the camera was set to take two shots that were about 2" apart then all you would need to do would be to set it on a little wider angle and move the camera in a sweeping (actually, a translating or sliding) motion while it takes 2 shots.

Then a little post processing to compensate for the change in camera angles between shots and an output file to display on those 3D hometheatres and Robert's your mother's brother.

Accelerometer needed for accuracy, but could be timed for a standard speed of movement.

Ling, Mar 25 2012


       Why only SLRs? I want this on my pocket camera. Perhaps best implemented in software on a smartphone which already has all the necessary hardware & processing power. Please link to the app once it has been created!
pocmloc, Mar 25 2012

       Fully baked (and works pretty well) in the Sony Cyber-shot DSC-TX55 as well as at least a few similar models.   

       "3D still image and 3D Sweep Panorama mode Produce awe-inspiring images with 3D still image and 3D Sweep Panorama capabilities. Images will take on a new dimension to view the world in a whole new way."   

       The 3D playback if pretty clever. They don't have a 3D display, but they have a gyro, so you can view the image at different angles by moving the camera.
scad mientist, Mar 25 2012

       I had a digital camera that would take three shots in rapid sequence, each at a different exposure (I think it was). I used it to take 3-D cloud pictures from a moving airplane.   

       BTW, both shots of a stereo picture should be taken with the camera(s) pointed in the same direction, not at a converging angle. When I was using two disposable cameras, I taped them both flat on a clipboard.
baconbrain, Mar 25 2012

       // I had a digital camera that would take three shots in rapid sequence, each at a different exposure //   

       My Mom had one like that as well (I think). It was great for constructing 360 panoramic mosaics, because you could pick and choose from the different exposures to make smooth lighting transitions. The 3D thing never occured to me, but photography's not really my medium.   

       The exposure times on this camera were pre-set, so it might not be the same kind.
Alterother, Mar 25 2012

       //My Mom had one like that as well// [marked-for- tagline] Also, when you start a sentence like that, some people expect it to go a certain way.
marklar, Mar 25 2012

       It's a good thing I stopped where I did, then.
Alterother, Mar 25 2012

       [scad mientist] well, I guess it is baked. Does it work like the panorama shots, with a fairly long time between successive exposures?
Ling, Mar 29 2012

       Yes, there would be some time between exposures. If you take this kind of 3D photo of a moving object, when viewed on the camera it creates a 3D+animation sort of effect which doesn't look bad, but if you were to view it steroscopically it wouldn't work well. The time between frames depends on how fast the camera is moved, but if you move too fast, the camera complains. I'd estimate that the minimum time between first and last image is about a second.   

       Interestingly the camera must be rotated, not just moved straight sideways. I assume one reason for this is that the camera has a gyro but no accelerometer. My first impression was that the panning would result in more blurring than you would get if you could just slide the camera sideways, but this has image stabilization so that might not be a problem. After thinking about this more, it seems easier rotate the camera in a uniform way than to move it sideways while maintaining the image centered in the screen, so this design is better for that reason.   

       If you rotate the camera but keep the center of the camera stationary, it will take multiple shots and composite them, but there will be no 3D effect. That isn't useful, but it is nice in that you can control the stereoscopic separation by adjusting how far in front of the axis of rotation that you hold the camera. At arms length, you get a couple feet of separation.   

       When in this mode, the left 3/5 of the screen is darkened to indicate that the dark portion will not show up in the final image. I originally assumed that this would mean that the width of the final image would be reduced, but it turned out that I got a 3D image that was the same width as a normal frame. To take the full image, the camera must rotate ~30 degrees. No object that is visible at the starting angle is in the frame at the ending angle. Therefore I conclude that the camera is doing some compositing so the left portion of the final image uses the center frame as the "right eye", but the right half of the image uses the center frame as the "left eye". I assume it actually uses many more segments of the screen rather than just left/right to avoid a sudden discontinuity in the middle of the screen, but it does seem like there would be added distortion, especially for close objects since each single view in the final image is a composite of images from different angles.   

       So I'd say this 3D method is not as good as an actual steroscopic camera (not simultaneous, and potential distortion from panning instead of pointing the camera in the same direction for both shots), but it is a nice add-on feature for a camera that has a gyro already for image stabilization and the capable of high frame rate photos.   

       This camera also has two other 3D modes that I haven't explored.
scad mientist, Mar 30 2012

       [scad mientist] thanks for taking the time to explain . I suppose all the bases have been covered.
Ling, Apr 01 2012

       That's definitely _not_ the camera my mother had. Hers just did the triple-exposure thing, not all that other fancy stuff.
Alterother, Apr 01 2012

       //Why only SLRs?// I'm also (still) wondering that. To me, an SLR is a somewhat fancy camera, and I can't quite see what the advantage is of using one here.   

       In fact, essentially all recent cameras are SL, the R being done in solid state electronics and software.
spidermother, Apr 01 2012

       I guess I was referring to a digital SLR which would not normally come with panoramic modes. Some of them allow the mirror to be locked up so that I suppose the rear screen could be used for panoramic type stitch functions (real time). But the models that have fairly standard mirror function preclude the use of the rear display as a means for actually taking the photos. Hence I believe post-processing is the only way for a 3D option.
Ling, Apr 01 2012


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