A simple modification to convert an LCA+ Instant Back into a stand-alone homebrew pinhole camera, using only a few things found around the house, and only taking 30-60 minutes.
I love pinhole cameras and I think instant cameras are neat, so I thought the two ideas should be combined! After thinking about it for a while, it was time to sit down and make it happen.
The idea is to take the empty instant film pack and attach it to the front of the Instant Back, where the LCA camera would normally go. First, the empty film pack is prepared: I removed the loose plastic pieces that the films sat on. Then I used those pieces of plastic to build up the ‘face’ of this, to fill in the holes where there should not be holes, and to make a new hole in the middle where the pinhole would go. I used the black electrical tape to connect all the pieces, and to ensure there were no extra holes or gaps.
If you don’t have an empty instax film pack you can use cardboard to build up a ‘box’ shape that will fit the LCA+ Instant Back. The dimensions are not critical, it is more important that it is sturdy and fits well enough that you can keep out unwanted light.
The new pinhole is made with a piece of tinfoil, taped into place and then a very, very tiny little hole is carefully poked into it. The hole should be round and very small. About 1/5mm across. It takes some practice to get this right. Black electrical tape is used again, to hold the tinfoil in place.
The last step is a shutter. The easiest way is just a piece of cardboard or left-over plastic that you can tape at one edge, to lift it up or down. I prefer to over-engineer things though! So I used some left-over plastic and cut it into a shutter shape with a handle. I made a small hole through everything, and then used a small screw to fasten it down. So it rotates open and closed.
The last build step is to attach the pinhole camera assembly to the front of your LCA+ Instant Back. Once again, I used black electrical tape to fasten it all securely and then used more tape to make sure it was light-tight.
To take pictures, I first measured / estimated the specifications. The pinhole is about 30mm from the film, and it is about 0.2mm in diameter. This means our focal length is 30mm and our aperture is about f/150. Instax Mini film is rated at ISO 800. With these figures, you can estimate the exposure times. For me, outside in an overcast day, was between 3 and 6 seconds per image.
The indoor pictures were much darker – with pinhole cameras you have to deal with reciprocity failure in film and this means exposure calculations stop working normally when you get into many-seconds or many-minutes of exposure. Indoor shots would take over 150 seconds when you think they would take only 30 seconds.