eddie
14-Mar-2009, 05:36
hello all,
i am having trouble with trying to determine a lens formula using the reflections i see while shining a light in it.
i have a few lenses that i know what they are. petzval, RR, etc. i am still having trouble "seeing" it. and then to make it worse when i put the elements back into the barrel and try to do it assembled i am lost.
does it matter which end i shine the light from? am i looking for strong and weak reflections or big and small? how close should i hold the light? what kind of light works best? any tips on figuring it out with out disassembling the lens?
thanks for the help.
eddie
i am having trouble with trying to determine a lens formula using the reflections i see while shining a light in it.
i have a few lenses that i know what they are. petzval, RR, etc. i am still having trouble "seeing" it. and then to make it worse when i put the elements back into the barrel and try to do it assembled i am lost.
does it matter which end i shine the light from? am i looking for strong and weak reflections or big and small? how close should i hold the light? what kind of light works best? any tips on figuring it out with out disassembling the lens?
thanks for the help.
eddie