You could use shoeboxes, like we used to do way back when when I was in highschool.
Of course, your focal length is going to vary- Students with little feet will be able to take wide angle pictures! On Mon, 13 Aug 2001, Chuck Flagg wrote: > > I have my students use "chip" cans like Fritos, Doritos[holds 5x7]. We > wipe out the oils, spray the inside with flat black paint. We use old photo > paper bags to cut a circle to fit inside the clear lid. We attach it with > spray contact cement. The outer edge is covered with a strip of black > electrical tape to discourage light transfer. > They are very durable and handy. I also make a lot of use of snack[holds > 3.5x5] & regular[holds 2.5x7+] "Pringle" chip cans. > Happy Shooting! > > Chuck Flagg >