Pinhole camera ides - NEED HELP

[scott.eyre`]

Hi

I had a few ideas foe pinhole cameras but need help on making them work properlu.

The first idea was to use a 35mm film canister and have the film slide through slits in the side of the canister and have the film up against the inside round back of the canister, However I want the camera to be able to use a whole roll of film slide through the canister.

LINK

Any ideas on how I can have the film hugging the back of the canister so I can wind on new frames and use a whole film?

I intend to make a box around the camera so it is light tight too.
I want the film to have light fall off on the negative and I assume it will provide a wide angle and distorted image that goes out of focus around the edges.

The Second idea was to use one of those peep holes found in hotels etc for a lens. Not sure if it would work or not but its worth a try.

Dead Link Removed

I would basicly make a box with the lens on it and use tracing paper to see if the lens focuses light properly and if it does make a basic camera out of it.

 

[Jeff Searust]

On the film canister idea you are thinking too tiny. See if you can do this with at least a 1.5 inch or so curvature. Maybe use a pvc pipe.

 

[DWThomas]

You might be able to have a pair of wheels, one at the top and one at the bottom -- maybe with a flange on them like a railroad wheel. Have the spacing such that the film sprocket area rides on the wheels and forms the cylindrical shape. If they are low friction and all the other parts of the film path are lined up, you might be able to hold a cylindrical shape that way. The wheels need to be on bearings without a shaft between them so there's nothing blocking the active part of the optical path. That might tend to call for some machine shop type work to fabricate parts. For a one-off project in 35mm size film, those mechanics are going to be small and tedious to work with though.

 

[Rick A]

Why would you need the film plane to be curved, when you are basically using a fish-eye lens. I would think the curvature might cause part of the negative to be out of focus, and have reflections if the radius is too small (ala your example w/film can). I think a larger radius so the film isn't acting like a mirror (say, oh, 2" or more)for the panorama effect. For making film guides easier,I would run the film on the outside of the curve and past a cut out "window" the size of your choosing. If I didn't have to be somewhere shortly, I would make an example for you.

 

[Shadowtracker]

Even if you can do this on this small of a scale, chances are pretty good the only way you would be able to make sure the film is hugging the back of the container, be that a film container for 35mm or even a pvc tube, would be to have a sprocket similar to what a camera has in order to advance the film while it lays in the area you want it to.

The only way I can think of where this would not be true is if you have a take-up reel to spool the exposed frame on and tracks similar to a sheet film developing holder curved in the exact shape you want the film to move. You might be able to get some kind of plastic to act as the rails which will guide the film along the curve. But the curve has to be large enough to not hang up on the base of the film.

Also, loading something that has a u shape rail on top and bottom of film will cause film-loading problems initially.

Good luck on the project and let us know how it turns out.

 

[SMBooth]

Is this more like what your thinking > http://www.f295.org/Pinholeforum/forum/Blah.pl?m-1268590426/
I would think your slits will scratch the film as well

 

[grahamp]

You could cut a slot in the 35mm can and run the film around the outside. I have a 120 format panoramic camera that runs film around 120 degrees without rollers - just guides.

But a 35mm format pinhole camera with a focal distance of under 25mm is going to need a very fine pinhole to be worth doing. And if you put the pinhole on the circumference of the cylinder the distance to the curved film plane will vary. To use a curved film plane you normally use a half cylinder and put the pinhole in the middle of the flat face to get a constant distance along one axis of the image. You still get light fall-off.

 

[Rick A]

You could rob the innerds from a flea market box camera, or just modify one, to obtain the parts for film advance, tensioners and the like.

 

[bsdunek]

As for your 'peep hole' lens. Back in about 1965 I used one on my Retina Reflex. You can't just use the peep hole as it doesn't project a real image. It's made to look at with your eye. I mounted it on a lens cap and put it on the front of the lens. With a 50mm lens the circle is pretty small. It worked pretty good with the 135mm lens. I later got a Kenko Fisheye adapter which worked much better.

 

[erikg]

There are a number of plans for matchbox pinhole cameras out there. Here is one. Link

If you want fall off you just need to have a big enough piece of material behind the pinhole to get as much of the image circle as possible. Also a cylinder will give you less fall off as you are keeping the film plane distance from the pinhole more constant. You don't actually get in and out of focus areas with pinhole, that is a characteristic of lenses. Have fun!