Thanks for the comments, I might just go with a pre-made laser cut sort, or indeed use a pin/needle of a certain size, for a sheet of 5x4 the optimal specs are apparently:
Focal length = 6.4"
Pinhole diameter = 0.54mm giving F302
Angle of view would be 53 degrees
I'm going to get some materials together and have a look at some designs, I need to get development equipment together as well so I have a bit of time before I will be taking any shots with it!
Playing around with some numbers I have found this to be perhaps something to aim for:
60 degree FOV
3 second exposure on a sunny day with ISO 100 film
Looks like if I aim for a pinhole at around 0.5mm and a focal length of around 5.5-6" it should be good for a 5x4.
Last edited by m1tch; 11-29-2012 at 08:17 AM. Click to view previous post history.