Ok, the goal is to get a 28ish 24x56mm images onto 120 film.
Better than getting an xpan or a swinger, I think I can mod my 645 to do this?
I'm currently shooting w/ a Mamiya 645 w/ 80/1.9 and 45/2.8. I'm willing to sac off a back to do this.
I will need to machine a darkslide. It has to have a centered 24x56mm image opening. Also, It has to be notched so the camera thinks that it is not there and will still let me continue to shoot. That is the easy part.
This will get my 15 images on a 120 roll. But, I am greedy!
I want 28ish images.
This is where your expertise may come in.
The camera need to advance the film to to proper '1' slot. Then each additional crank should only advance the film instead of 60ish mm to 30ish mm. I also need to trick the back to use the 220 counter to let me advance to 30.
The counter is done w/ a tab on the insert. I'm probably going to have to loose teeth on the gear connecting the back to the body or machine a pair of new gears to the "right" ratio. But I'm not sure how that affects film advance to "1".
i mean... this way i get an actual image, two stops faster, no major wide angle distortions, no center weighted filters -or- no banding possibilities, no locked in at a fixed focus distance, no locked in shutter speeds.
Doing something genuinely alternative won't get you many replies haha.
Interesting none the less, I'd love to hear how it goes. A mask over the film and a different gearing for the advance should do it. The m645 1000s is easy to take apart but you sacrifice your leatherette and the screws are TINY
Changing the number of teeth on the gears won't help you with limiting the advance, you will need a different ratio (smaller/larger gear) I imagine it will be very tricky to work out.
I've had a similar idea recently: to modify 135mm film holder to expose 24x56mm images. One should rewind 2 times for every actual image taken (even numbers on the counter). Those in between (odd numbers on the counter) should be taken with modified dark slide that should allow pressing the shutter with the slide mounted or with the lens cap mounted and darkened viewfinder. This way 18 panoramic pictures could be taken. That would be less than your desired 28 but nevertheless...
Now, what could one do with a modified RB/RZ film holder, 69x??mm panoramic image?
How about not modifying the gearing of the back, and instead of cutting a centered hole in the darkslide, how about just cutting the darkslide in half? Does it go in from either direction? If so, then just swap it out to the other side after exposing the first half of the film. People do this (longitudinally) to do 4x10 images with an 8x10 camera. E.g. a half-darkslide splitting the film into 2 4x10 exposures.
Just a thought. Not sure if it's feasible or not but it's easier to try than modifying gearing.
Another option (albeit way more work) would be run the film through the camera twice. the 2nd time around, advance another half-frame beyond the start point, so the new images are offset by the 28mm or whatever the width of the image is. Requries rewinding the 220 film though = darkroom or changing tent. Much more hassle but doable without modifying the camera (some trial and error required likely).
@ed - it's absolutely impossible to rerun 120 film. the 1/2 frames isn't bad, but it might be too slow to photo street.
@jtodd - you get 2-3more stops and close focal length w/ an slr over the xpan.
@mirkoc - i thought about that, even bought a 35mm back. but it doesnt seem to work out because the insert is too narrow and there is no pressure plate for the rest of the image.
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How about this, simple to start w/...
Same dark slide.
I think I can advance to 1 w/o modifying the back. There's a little connection that enables film advancing, set that in. so the backs cranks will work. Then set it to multi-exposure. Figure out how many clicks to advance the back and keep the count in my head?
Sorta like a holga w/o the red window.
I still rather the gears just go and shoot quickly.
ewah wrote:
@jtodd - you get 2-3more stops and close focal length w/ an slr over the xpan.
The Xpan lenses are f/4, right? Then you get one or max two (80/1.9) stops more, not 2-3.
One idea is to separate the shutter cocking mechanism from the film winding. Then you could cock the shutter without winding a full 645 frame each time.
It's probably not easy, but doable, which I don't believe it is to change gearing.
Makten wrote:
One idea is to separate the shutter cocking mechanism from the film winding. Then you could cock the shutter without winding a full 645 frame each time.
It's probably not easy, but doable, which I don't believe it is to change gearing.
multi-exposure is going to be the easiest method, agreed. And doing half-frame advances through some calculation or setting a stop on the winding crank, probably.
