Originally Posted by scottyb70
Here, I read somewhere is you scan the pinhole, zoom it up and count the pixels. Divide the pixels by the resolution and you have your fstop.
Divide the number of pixels by the scanning dpi, which gives you the pinhole's aperture diameter
To determine the f/stop you then need to do a little math OR plug in both
the diameter and your pinhole camera's focal length into one of the online pinhole calculators . I use this one:
I wrote a bit on making your own pinholes here:
Solargraphy can be very interesting! Here is one that I exposed for 4-days:
I hope you all give solargraphy and pinholing a try!