In my blog the coffee camera was very well mad and every time you have to test the light, first time we went out we just tested the light. then we tried 2 minutes then 1 then thirty seconds then 10 and it worked perfectly. our picture came out very nice and perfectly negative. with the coffee camera you cannot have to much or to little light other wise it will not work. although or negative was not centered it is very hard to get the picture exactly in the middle.