Monday, 18 July 2011
Colour film in a point and shoot
Picked up a point and shoot olympus mju-ii in a charity shop and I have enjoyed snapping with it. The pictures have a certain feel to them that is quite fun. Here are a few:
Converting a cheap 35mm camera to a pinhole
I thought it would be fun to make a pinhole camera from a body of one of those really cheapo plastic 35mm cameras. The advantage of doing this is it is nice and easy to load up a roll of 35mm film to get pinhole images with. I finally got round to doing it, and thought I'd leave a 'how to' on my blog - though it is still untested as yet.
1. Get a cheap 35mm plastic camera from a charity shop, jumble sale or bottom drawer. It needs to have a sliding cover, and must not take a battery. Ideally it should also have a screwthread for a tripod as pinhole pictures need to be held on a tripod to be sharp.
2. Make a pinhole in a suitable material as described in many places on the internet. I found this site helpful: http://users.rcn.com/stewoody/makecam.htm. It can also be helpful, but not essential to know the actual diameter of the pinhole you have made. Measuring the pinhole is easy with a scanner. Scan the pinhole at a high resolution, and take note of the resolution (eg1200dpi), then zoom into the image and count how many pixels your pinhole is across. Divide this number by the resolution to give you the diameter of the pinhole (eg 18/1200=0.015inch)
3. Get some tools handy: a really small philips screwdriver is handy - I got a cheap set of small screwdrivers from Wilkinsons that did the job - a penknife and some superglue. Taking digital photos as you go along can be helpful although we shouldn't need to take too much apart.
OK, now down to business. The plan is to take out the plastic lens and shutter, and replace it with a pinhole, whilst enlarging any aperture that might block the edges of our pinhole (vignetting).
Take the front of the camera off. The screws for this were inside the compartment on the back where the film goes. I also took screws out of the bottom of the camera because they were there but soon regretted it as this was to access the film rewind mechanism, which I wanted to leave entirely intact, but proceeded to fall out as I opened the bottom!
Now I had a look round and worked out what did what. The lens and shutter were held in place by a series of plastic retainers/mounts that simply clipped onto each other. It was easy to unclip them and remove both lens and shutter.
I then decided where to mount my pinhole and I had a number of options of plastic surfaces that would take the pinhole, however, and this is the complicated bit, I also had to make sure the pinhole would be able to make a reasonable image and this takes a bit of maths. Let me explain.
1. The closer the pinhole is to the film plane the wider the field of view. This makes interesting pinhole pictures but unfortunately it can't be too wide when we make a pinhole in an existing camera case. By measuring the distace from where the pinhole will sit to where the film sits (the focal length), the following link will help you calculate the angle of view that your pinhole will give: http://www.mrpinhole.com/calcpinh.php. As long as the image diameter is bigger than 43mm the whole image will fit on 35mm film.
2. The problem is the hole at the very front of the camera. If you put the pinhole near the film you would expect to get a really wide angle of view, but the front hole blocks the angle. Alternatively if you put the pinhole right at the front of the camera it won't be blocked by the front, but it won't be as wide angle as you can get it, and it might be blocked by other holes in the camera that the light has to pass through. A happy medium in the middle is often best.
What I did was measured the distances to the front and to the film for each of my options and worked out the angle of view for each, to the film plane using mr pinhole and to the front using trigonometry, and chose the option that gave the widest angle of view for both. This turned out to be 34mm from the film for me and will probably be quite similar for most cheapo cameras. However, I also realised I needed to hack some of the holes to make them larger.
3. To maximise the potential of your pinhole, smaller isn't always better. Theoretically there is an optimal pinhole size depending on the thickness of the material used and the focal length. Mr Pinhole calculator will tell you this optimal size. It probably doesn't matter too much, and I had made a few pinholes, so I just selected the pinhole with a diameter closest to the one prescribed for 34mm. If you want to ignore the whole of this paragraph then please do so.
1. Get a cheap 35mm plastic camera from a charity shop, jumble sale or bottom drawer. It needs to have a sliding cover, and must not take a battery. Ideally it should also have a screwthread for a tripod as pinhole pictures need to be held on a tripod to be sharp.
2. Make a pinhole in a suitable material as described in many places on the internet. I found this site helpful: http://users.rcn.com/stewoody/makecam.htm. It can also be helpful, but not essential to know the actual diameter of the pinhole you have made. Measuring the pinhole is easy with a scanner. Scan the pinhole at a high resolution, and take note of the resolution (eg1200dpi), then zoom into the image and count how many pixels your pinhole is across. Divide this number by the resolution to give you the diameter of the pinhole (eg 18/1200=0.015inch)3. Get some tools handy: a really small philips screwdriver is handy - I got a cheap set of small screwdrivers from Wilkinsons that did the job - a penknife and some superglue. Taking digital photos as you go along can be helpful although we shouldn't need to take too much apart.
OK, now down to business. The plan is to take out the plastic lens and shutter, and replace it with a pinhole, whilst enlarging any aperture that might block the edges of our pinhole (vignetting).
Now I had a look round and worked out what did what. The lens and shutter were held in place by a series of plastic retainers/mounts that simply clipped onto each other. It was easy to unclip them and remove both lens and shutter.
I then decided where to mount my pinhole and I had a number of options of plastic surfaces that would take the pinhole, however, and this is the complicated bit, I also had to make sure the pinhole would be able to make a reasonable image and this takes a bit of maths. Let me explain.
1. The closer the pinhole is to the film plane the wider the field of view. This makes interesting pinhole pictures but unfortunately it can't be too wide when we make a pinhole in an existing camera case. By measuring the distace from where the pinhole will sit to where the film sits (the focal length), the following link will help you calculate the angle of view that your pinhole will give: http://www.mrpinhole.com/calcpinh.php. As long as the image diameter is bigger than 43mm the whole image will fit on 35mm film.
2. The problem is the hole at the very front of the camera. If you put the pinhole near the film you would expect to get a really wide angle of view, but the front hole blocks the angle. Alternatively if you put the pinhole right at the front of the camera it won't be blocked by the front, but it won't be as wide angle as you can get it, and it might be blocked by other holes in the camera that the light has to pass through. A happy medium in the middle is often best.What I did was measured the distances to the front and to the film for each of my options and worked out the angle of view for each, to the film plane using mr pinhole and to the front using trigonometry, and chose the option that gave the widest angle of view for both. This turned out to be 34mm from the film for me and will probably be quite similar for most cheapo cameras. However, I also realised I needed to hack some of the holes to make them larger.
3. To maximise the potential of your pinhole, smaller isn't always better. Theoretically there is an optimal pinhole size depending on the thickness of the material used and the focal length. Mr Pinhole calculator will tell you this optimal size. It probably doesn't matter too much, and I had made a few pinholes, so I just selected the pinhole with a diameter closest to the one prescribed for 34mm. If you want to ignore the whole of this paragraph then please do so.
So, after deciding where to fit the pinhole and hacking the holes larger (this was a laugh - I tried to use a drill but it didn't go very well so I simply cut with a penknife and tore at the edges with pliers - not the most elegant solution), I had to glue the pinhole in place. For this I cut the metal pinhole to size using scissors and glued it to the camera using superglue. A plastic retaining ring needed to fit back on top so I sanded a millimetre off its underside to allow for the thickness of the pinhole metal and fitted everything back into its place. The front could then be screwed back on, but it had occurred to me there was one last thing to do.
The new shutter for this pinhole would simply be the cover which slides side to side, however there was a mechanism to stop the shutter release button being pressed when the shutter is closed. Because the shutter is now defunct I wanted to stop this, but I wanted to retain having to press the shutter release as it would stop me advancing the film too far. So, I had to work out which bit of plastic to cut off to allow the shutter to be released after I had made the exposure and closed the cover.
I had fun making this and will enjoy experimenting with its pictures. I fancy making a similar camera, but retaining the shutter, and using a large pinhole (0.5-1mm diameter). On a sunny day I should be able to handhold the pinhole camera if I use fast film.
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