Pinhole photography is a very interesting medium. It forces you to think about the shot a lot more due to the calculations that have to be made for the correct exposure and the shots are usually a lot more old fashioned, abstract and even downright bizarre. Buying a pinhole camera or even making one needn't be a worry now as The Pinhole Factory have a body cap adapter to take pinhole images on your 35mm or digital SLR.
Digital SLR pinhole photography
The adapter screws onto a simple T2 mount or for a small fee of £10, you can have your body cap converted instead. When going out to take pictures, a light meter is recommended although taking a spare lens and using the camera to get a reading is good enough. Mathematics have to be implemented in conjunction with the calculator that is simply two pieces of card that rotate to give corresponding information. The equation is focal distance of pinhole to sensor (d) divided by the size of the pinhole (p) which gives the aperture. For instance if d was 3.5in and p was 0.018, then the equation would be 3.5 divided by 0.018 which gives a total of 194. So from that, we can ascertain that the aperture is f/194. Use the chart to align the shutter speed and aperture that the lens or meter gives then take the shutter speed that is aligned with f/194 and this gives the shutter speed reading for the pinhole shot.
It's technical stuff and could put some people off but once you have got used to it, you will find it easy to work as the aperture remains a constant, so the maths only have to be worked once.
When I first took the images, they came out badly focused and this seems to be a problem with using a digital SLR to take pinhole images. Theorising on this subject brings up a few ideas: The sensor on a digital SLR only takes light from straight on and because the focus area of a pinhole image is in the centre, this could cause problems. A teeny tiny aperture like a pinhole means massive depth of field. Depth of field should bring everything into focus but depth of field and depth of focus are two different things. So that could mean that the focus plane is too close to the sensor for it to focus. Logic dictates that the pinhole should be moved away from the sensor to correct the problem so extension tubes are the answer to that. After trying the extension tubes, the image never came closer into focus, so that could mean that the depth of focus is so fine it is not possible to get an extension tube to get it right, so some bellows may be the answer. However, the bit of fun is starting to get serious in that case. Also, the focal point may be inside the camera body meaning that the image would never come into focus.
Interesting images can be made with everything out of focus. I tried a self portrait silhouetting myself and it doesn't have to stop there as any object that is easily recognisable could be used.
To stay in with the older style of photography, I have taken an image of a pocket watch, some poker chips and some cards to give the sense of the old days. Interestingly, it seems the pinhole adapter has another use as all the dust on the sensor comes into focus. This adds to the ambience of the image followed by dirtying it up in an editing suite and giving it an older feel with a ragged edge.
The novelty factor is the only thing that keeps the adapter from a miserable score as the out of focus images fly in the face of what photography is all about. I really enjoyed my time using it and finding suitable subjects to use was part of the fun.
The poor performance of the adapter actually benefits as it forces you to think about your subject and it's nice to have one in your bag in case a situation presents itself.
Pinhole adapters cost around £30 for the adapter and another £10 for the appropriate T2 mount and are available from P&L Solutions here.