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Movable imaging sensor

Take pictures of tall things without distortion
  [vote for,

The old bellows cameras of the 1940's may in some ways seem quaint and obsolete, but some of them possessed a feature not found in newer cameras: they could position the lens so that it wasn't in front of the center of the film, but rather significantly above it. Doing this would yield a field of view which was similar to that obtained by pointing the camera upward, but since the film plate would be vertical and the axis of the lens horizontal, the sides of buildings would appear straight and parallel.

Allowing a camera's lens to move without creating light leaks can be difficult. An easier approach may be possible, though: move the imaging sensor. Since the imaging sensor on a typical digital camera is quite small, it would not have to move very far--only by about half its size. It would require somewhat larger optics, but probably not unreasonably so.

BTW, I'd also like to see something similar done with digital projectors. When placed on a table top, they generally have to be angled upward to project nicely onto a screen. If the imaging LCD were moved, however, the lens axis could be horizontal and the LCD vertical while projecting the image upward onto the screen. This would avoid the keystoning and focusing problems for which projectors' fancy electronics try to compensate but don't perfectly succeed.

supercat, Aug 03 2003


       These are super-baked for photo. They're called "tilt-shift" lenses, and are generally very expensive...
DeathNinja, Aug 03 2003

       I know they exist for film cameras. Ever heard of such a thing for digital? It would seem the smaller image sensors of digital cameras would make such a device considerably easier to produce than it otherwise would be.
supercat, Aug 04 2003

       Surely this is something that should be done in post production on the PC, rather than physically in a camera?
FloridaManatee, Aug 04 2003

       Some photographers are detail-obsessed and want all the pixels they can get in the image itself, not fake it at the editing table.   

       There are digital backs for medium-format cameras (for which tilt/shift lenses are readily available as well); they're still very expensive, though, so people often just rent them.
jutta, Nov 25 2004

       [jutta], With a digital back, you can use a view camera with rear-standard movements to achieve the effect, but then you are using a big heavy expensive view camera, and digital backs are super expensive.   

       [FloridaManatee], you can tilt the camera to get the whole building in the frame, and then correct the perspective afterword in photoshop, but then you lose resolution and as a result are not able to enlarge the image quite as much.   

       What [supercat] is suggesting here could be achieved in a package that is just about the same size as an ordinary digital SLR, and would be better than a tilt/shift lens because you would be able to basicaly make all your favorite lenses be tilt/shift lenses on the camera, so long as their image circles are large enough, which is the case for most 35mm lenses on D-SLRs.   

       The best way to think of a shift, rise, or fall movement is that you have a frame that is larger than your actual sensor size, and with the movement you are selecting exactly where within that larger frame you want the picture to be taken. Side shifts are also useful for taking multiple exposure panoramas, without needing a special tripod head.
JakePatterson, May 29 2005

       JakePatterson--You seem to understand pretty well what I'm describing. Another feature: when photographing a flat object using flash, using a significantly-off-center portion of the image can help to avoid the 'hot spot' that can occur with glossy or semi-glossy finishes.   

       BTW, as digital cameras' resolutions have improved to the point that digital zoom can sometimes be useful, it should be possible to implement this idea to a certain extent in software by having the camera photograph an off-center portion of the image sensor. To be sure, that effect could be obtained post-production by simply snapping the whole unzoomed picture and then cropping the unwanted parts afterward, but that would take more storage space and hassle.
supercat, May 29 2005


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