Just bought one of the spinners. Great fun!
Matt, I understand and share your confusion; this is certainly an exercise for one's brain.
As good of an explanation as I can come up with is the fact that you can take a picture of a mirror, as though you were in front of it, but with no reflection of the camera in the mirror, by utilizing shift. But that's no explanation, is it... :/
I'm trying to reason this out and I'm hitting brick walls in my brain... I think that you're right that shifting will move the image, and thus you need a slit to isolate a region. But then I start thinking about the fact that this image is flipped and my brain starts to malfunction, I hit Cntrl+Alt+Delete and nothing happens.
But the lomography spinner is another example of what I think proves my theory. And yet again, I can't quite put it into words.
However this is a camera-building thread, so let's stick to that.
I'm glad we're sorting it out... we need a slit-scan expert STAT.
As per your first post; I am glad you are not using concrete.
Why are there no speaker jacks on a stereo camera?
actually the equivalent has already been done. there was an artist at Laguna Beach Festival of the Arts who runs 70mm or 220 through a Hasselblad continuosly with a slit lens photographing a moving subject (cars going by, marching bands, etc)....
there is also a scheme to rotate the camera on a turntable for stationary subjects.
BTW: this is what the Betterlight scan back does in panorama. it parks the sensor in the middle of the Field of View and then rotates the camera at the right rate to make the 360 degree panarama
There are many analogues, but do any of them have stationary film with a moving lens?
MattKing has definitely placed doubts in my mind as to whether it would work like I had envisioned. I've got to devise some kind of test...
I'd love to see this Laguna Beach artist though, that sounds great!
And luckily I'm not a materials engineer.... I have very few concrete ideas........ cue: *laughter and applause*
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How about testing using a shoe box and about a foot of film?
Originally Posted by holmburgers
“Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”
Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2
Good idea. I was also thinking about doing something with ground glass or tracing paper and drawing what I see; crude but would at least help me visualize it.
I'll see about doing something over the weekend.
So you want the lens to translate during the exposure, not swing as in, e.g., a Kodak Panorama camera or a Widelux or in the aerial cameras I pointed out to you.
Originally Posted by holmburgers
I don't get the point of it, but that's just more proof that I'm not imaginative.
Why don't you simulate the effect by setting a camera down first at one end of a yardstick on top of a tripod, then at the other, and taking an exposure from each position with the camera pointing straight ahead. Nice simple feasible proof-of-concept prototype. If the two shots or narrow sections of them give you the effect -- with the middle missing -- you want, wonderful. If not, reconsider what you're trying to accomplish.
When you think of the mechanics, an electrically-driven translating lensboard shouldn't be too hard to make. But, as I've already said, I can't grasp why you want to do it.
I want to make it because I like to keep on the tradition of photographic invention. What if George Lawrence had never decided to make a camera that could be flown by a kite? We wouldn't have this picture...
What if F.E. Ives never invented the Kromskop? We might not have color film!
What if Edwin Land never invented a film that could develop into a print instantly! We might not have digital cameras!
.... (i'll stop my work immediately)
Ok, sorry, got carried away.
But seriously, why not make something if you've got an idea and you think the result could be worth the effort to achieve it?
I have learned something more about this in the meantime. I took out my view camera and made a slit by masking a filter with some painter's tape. Just two pieces that left about a 5mm gap for the lens to peer through. The funny thing is that in either case (in front of lens or behind lens), a full image appeared on the ground glass.
Looking back it's obvious that a slit that close to the lens would act just like a waterhouse stop, but one important design feature is that the slit has to be as close to the image plane as possible to achieve a well defined beam of light.
And since the slit has to move with the lens, the lens mount will have to protrude back and hold the aperture slit recessed in the cavity.
So this discovery delay's any test with my view camera as I was going to observe how the slit moved across the ground glass.
Last report for now, but I found a mailing tube, cut it to 140mm, secured it to the back of my 135mm Raptar's lens board and on the end of the tube nearest the film plane was my slit.
Matt was right in that it will basically double-expose the image and I was totally wrong about not needing a thin slit. The wider the slit, the more area that is being exposed in a single moment. Imagine a diagonal line in your subject. If it's a wide slit that encompasses the diagonal it'll end up as a neutral gray because the whole line will sweep across the film. But if it's a thin slit, a smaller section of the diagonal line will be seen by the film at a given moment and thus it'll register as a line (but thicker depending on the width of the slit).
It's a very weird thing to observe; when you shift the lens left or right the slit will move at one rate and the image will move at another. So I think it'll take your subject and stretch it very interestingly. Perhaps it could "smushed" back in post production or in analog terms, by an anamorphic lens of some sort.
And indeed, when you swing the lens, the subject remains motionless on the ground glass and the slit scans across it, like shining a flashlight in the dark. This is what the Widelux, Horizon, et al., do; pivot around the lens' nodal point.
So with a thin slit, the image will be discernible as your subject, but with a yet to be envisioned blurry appearance.