I've decided to get back to using my Holga, and while in the past I've been happy with the the pics I have taken, I started thinking about how "accurate" the settings on the camera are. (Yes I know that you are supposed to accept what you get with this sort of camera, but dammit, I want to know!)
The camera is nominally f/8 or f/11 at 1/100s. But how would I prove this?
I can imagine using a light sensor to help measure the shutter speed by looking at the light profile over time, but how would you measure the f-stop?