Preparing the Zero Pinhole Camera for use.

Using this camera is a real step back in time requiring you to put aside all those luxuries that the modern photographer has taken for granted. After all, it is just a box with a pinhole in it, the ultimate manual experience from loading the film and remembering to wind it on, to calculating the shutter speed.

Loading the film:

To start with you need to load a roll of film. That's obvious, most film cameras need film to work. If you are like me it has been a long time since you looked at the backing paper of a roll 120 film. I had forgotten that it is marked for the four different sizes in the 120 family and with the multi format camera it has three red coloured windows in which to view the film numbers. It also has a set of symbols that tell you when the number is about to appear in the window which also marks the middle of the frame. With this set up you cannot blame anyone else for winding it on to far, so it is a good idea to take it slow and gentle in the beginning. Before loading the film you need to set the format your going to use, once the back and top are in place, it is time to advance the film so the light-sensitive material is in front of the pinhole. When winding on you may notice that it becomes quite tight, this is where the celluloid attached to the backing paper is being drawn in front of the light box. Just continue gently on until the first frame number appears behind the little red window. Now the camera is primed for light capture.

Calculating exposure;

The Zero cameras aperture is set at F 235, it is important to remember this as this number is not written on the calculator attached to the back of the camera. The calculators outer ring shows shutter times from 8000 ths of a second too 15 hours, the inner ring shows F numbers from F 1.4 to F 500.

Please note that all the figures that follow are based on a film speed of 100 ISO.

Today, for example, my light meter is showing a light reading of F 5.6 @ 500 ths of a second. Now using the calculator move the dials so F5.6 is opposite 500 ths of a sec., then find F 235 on the outer ring and read off the time opposite which is about 3 second; you will need to make an adjustment for reciprocity effect by a factor of 2 making an exposure time of 6 seconds. I say 'about' because the next F number is 250 with an indicated shutter time of 4 seconds. To start with it is a bit hit and miss, that is why it is a good idea to make notes on shutter times so you can see where to make adjustments once the film has been developed.

You will need to make adjustments for the reciprocity effect as follows:

• From 1 second and over compensate by multiplying by 2 giving an exposure of 2 seconds.
• From 5 seconds and over compensate by multiplying by 5 giving an exposure of 25 seconds
• From 50 seconds and over compensate by multiplying by 12 giving an exposure of 600 seconds/11 mins.

Reciprocity How it may affect monochrome film

The use of a Zero pinhole camera means that long exposures are the norm. It might be a good idea to give an insight into how reciprocity affects the negatives. It is a wide-ranging subject that afflicts colour and black and white materials in different ways at long exposures, extremely short exposures and with flash. Because of this I am limiting this post to long exposure times with black and white film.

The Law:

The formula E=IxT expresses reciprocal relationship between the intensity of light reaching the film and the time allowed to act on the film. If one increases the other decreases proportionally, no net change in exposure occurs.

Ansel Adams The Negative.

At long exposures this law breaks down, known as reciprocity failure. It is where a seconds worth of light is not enough to satisfactorily produce the required densities in the negative. So the longer the exposure the greater the compensation needs to be. With these exaggerated times comes a side effect in that the lower values recorded become under exposed more than the higher ones causing the contrast of the negative to increase. You can make adjustment for this when developing the film by a reduction of ten percent for up to ten seconds, from ten seconds by twenty percent and from a hundred seconds by thirty percent. These changes are easy to control for single frame exposure made with large format cameras but a little difficult to achieve with roll film. If all the frames on the film are exposed for no longer than ten seconds then the ten percent reduction will control the increase in contrast across the whole film, but in practice this is not always the case with exposure times being all over the place. I would suggest that a reduction of ten percent be the starting point and that with experimentation will find what works best for you. Having said all this the side effect of higher contrast maybe to your liking in which case where's the problem.

Further reading

The picture included in this post shows a slight increase in contrast. The negatives Ilford FP4+ were processed in PMK Pyro without an adjustment for increased contrast. Printed on grade two multi grade paper developed using Moersch 6 blue.

The following images and those above were all made using a Zero multi format Pinhole camera. The pictures below are from negatives using Fomapan 100 at box speed developed in studional for 11 minutes. scanned from photographs printed on Ilford multigrade 4 developed in souped ilford multigrade.