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I am making a pinhole camera for a school science fair. Is it possible to use Instax Mini Film instead of the long process of developing photo paper? If so, would I use the same design, and just swap the film, or do I have to change the design of the camera?

  • Developing photographic paper is not a long process if you have the chemistry and a suitable space (which are perhaps caveats): 2 mins in the dev, optionally 30 seconds in stop, then 5 mins in fix. – tfb Mar 15 at 11:21
  • @tfb -- plus setup and cleanup. – Pete Becker Mar 15 at 12:53
  • @PeteBecker: yes a few minutes for that. What takes the time is washing prints, but you don't really need to do that for RC paper. I'm not arguing that it's as fast as the instax, just that it's not hours: I can do 20 contact sheets on RC in an hour, including everything bar waiting for the sheets to dry. – tfb Mar 15 at 13:25
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You definitely have to change the design of the camera. This HowStuffWorks page explains how instant film develops well enough. Essentially, the film cassette contains rollers that roll out the developer to begin developing your film. Until this happens, the film is still light sensitive.

This is why the cassette begins with a plastic, light blocking layer that must be ejected once the cassette is in the camera. After this, the next shot exposes onto the film, which is then ejected, smooshed through the rollers, and begins development.

It'd be fairly impractical to pull the film from the cassette in a darkroom, load camera, shoot, go back to darkroom, use rolling pin on film. Instead, you should utilize the cassette as it was designed.

This means modifying your pinhole camera to load a cassette and provide a pathway for the ejecting film that doesn't compromise the light-tightness of the camera body. It also means adding some batteries and doing some electrical work so as to get the cassette to eject the film on a button press. Yanking the guts out of an Instax camera may help here.

Or, take the simpler approach and buy something like this instant back which already contains the electronics and film eject button in a nice and neat package. Simply build up your pinhole camera around it for design. Or this one, which appears to not need the electronics.


Edit to add: So, I sacrificed a cassette for you. You could get away with a completely mechanical design if you shape it up around existing processes. For example, the cassette exposes the film on the bottom corner:

Images shrunk for inline reading. Click to expand

enter image description here

And here's my Lomo's method of ejecting it (actuated):

enter image description here

And not actuated:

enter image description here

You can see how the metal has a hooked groove meant to grab the exposed film and push it up out of the camera. It only pushes it a bit, then the user is expected to grab and pull it the rest of the way out.

  • Ok, I don’t know much about film photography, and the project is due in a couple days. You’re saying I can use the film, and develop it manually with a rolling pin, or I would have to integrate the cassette I to my camera? I don’t have time to do anything complicated, would the cassette method be difficult? – Redline Mar 14 at 18:48
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    @Redline I'm saying that first, you need to understand how the film works. Read the linked article. Second, you can replicate this action using a rolling pin, but it would require you to load the film in the dark, expose it, go back into the dark, and roll it out. Which is honestly even less practical than just using photo paper and developing after exposure per most high-school pinhole cameras. – Hueco Mar 14 at 18:59
  • @Redline So, you are left with building a camera around the cassette. Fastest implementation would be to buy one of the two film backs that I linked to and to build up the pinhole camera around those. If not wanting to use any pre-fab parts, then you need to build a film-ejector mechanism yourself, which is a bit more complicated. – Hueco Mar 14 at 19:01
  • @Redline building a camera around one of the film backs is only as difficult as your lack of proficiency in either woodworking, metalworking, 3d-printing, or ghetto cardboard and duct tape skills. For example, I'm decent with wood and could have the camera built around a film back in ~1-2 days. If you're not, then it will take longer. – Hueco Mar 14 at 19:03
  • @Redline what are you doing to create the pinhole, btw? Have you done the math to determine pinhole size and ideal distance from hole to film? – Hueco Mar 14 at 19:05
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You can easily convert most any instant camera to a pin-hole camera without damaging the camera in any way. If you do what I tell you, your instant camera will perform exactly as a pin-hole camera, in fact, it will be a pin-hole camera.

With a sewing needle, pierce some aluminum foil. Center the hole over the center of the lens. Shape this piece of aluminum foil so that it is held in place by its shape. Be inventive, use double stick tape or masking tape to affix this pin-hole centered on the lens.

Even though the camera has a glass lens, you are restricting the light path of the image forming light to the pin-hole. This will negate the lens. The camera will become a pin-hole camera. The advantage is: The camera has a shutter and a mechanism to accept instant film. If fact Polaroid once marketed a high-end camera with a spring loaded pin-hole attachment.

Best of luck!

  • Yes, I am aware of this method. But as I am doing this for a science fair, I think I would be better of making one myself. – Redline Mar 15 at 16:38
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Edit: googling reveals "Developing and fixing chemicals are stored in the "sack" of white border on the bottom of the image and when the film is pushed out of the camera the developing process begins." -- so you may need to replicate this pushing mechanism, which may not be easy.

Old answer: Yes, you can do this. Do remember that if the Intax Mini Film is larger than standard film, to get the same field of view, you need to move it further back (increase the focal length).

A pinhole camera is just like an ordinary camera, just with a much poorer lens (slow and lacking in sharpness). So, anything that acts as a film will work.

Remember also to experiment with various exposure times, as changing the film may require changes to the exposure.

And, if you don't want to use film, you can also make a digital pinhole camera! Just find any old DSLR, drill a hole into the cap, add some tape over the hole in the cap and carefully pierce an extremely small hole into the tape.

  • But to get good results from the pinhole camera, very long exposure times are necessary. That might be a problem when using an old DLSR. – Uwe Mar 15 at 12:39

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