Cleaning Focusing Screen
Hi Guys- I have a Canon AT-1 here. The foam that the mirror hits when it opens to the top of the camera is falling off. I had the camera upside down and it blew into the focusing screen and got smudged. Now it seems stained. How can I clean the focusing screen back to normal?
I messed up my Nikon FM's screen and I tried everything except steel wool to get rid of the gunk. No luck.
Would a bleach/water solution put on a q-tip do damage or would it turn the black foam residue white?
Try using methanol. Most other solvents/cleaners won't dissolve urethane. The best cleaners for urethane are a mixture of solvents -- one is an alcohol and the other a halogenated solvent, but these may attack the screen.
use methanol/alcohol on a q tip first -use a rolling action to remove the black gunk as best possible..
it will still leave a mark on the screen, but this will be the best you cna do...only way to clean a screen correctly is to remove it and then wash it in detergent, followed by a final rinse in wetting agent..hopefully you can then get a dry screen (from my experience in camera repair I had a 60/40 success rate)..
And I'd forget removing the screen from a AT-1 - first you need to remove the top, then uncouple the wire that runs from the ISO dial to the shutter speed dial, then remove the main flex (without cracking it-a real problem on these as the flex is usually very brittle after so many years)..then remove the prism, and remove the screen form the prism....
Not a fun job!