This week I got an old SLR back from service, and I have a set of extension tubes for it. An idea came to my mind, namely to use one or more of the extension tubes with a pinholed lens cap or aluminum foil at front. I could even get a second extension tube set and use these ones separately as front tubes with permanent holes of different diameters that would fit different combinations of the other tube set.
Probably someone has tried this already, and if so I would be very interested in learning the outcome of it as well as in getting some suggestions for improving my idea. The best way is to try it out myself, but hey, I am the guy presently converting a (too small) guest toilet into a darkroom, and that keeps me busy enough for the moment. Dennis
