I made a pinhole for my monorail. I checked the charts (I think at Mr. Pinhole) to find a hole to film plane distance and pinhole size I could make. I used a piece of a soda can and colored it with black magic marker. When I shot, I just moved the front standard to the distance I chose when I picked the pinhole size, made the exposure (I used paper in the film holder so I could use a flap of matboard to cover the pinhole and be a shutter), and voila... I can't find the exposures right now, but I did get 2 decently sharp shots. I would think it would work just as well with a field camera.