Spot on Inside of Lens

[camera.bear]

Hey Everybody,

I got this 100mm lens to use with my Argus C3. I bought this on ebay and it came with a spot on the inside of the rear element. Does anyone know what it is and what I need to do to fix it or is it irrepairable? I tried to clean it but it is on the inside.

http://farm4.static.flickr.com/3213/3136277917_d9105b682b.jpg

[payasam]

Wayne, do you mean the smallest circle, the one with the red top rim? At the rear, such a thing could be dangerous.

[camera.bear]

I was able to solve this one. I took out the rear element which turned out to be an air-spaced doublet which had gotten oil between the lenses. I cleaned this and reassembled the lens. :D

http://farm4.static.flickr.com/3126/3140515354_bfde4a46de.jpg

I will be taking my C-3 and the 100mm, 50mm and 35mm lenses out for a test run this weekend. It should be fun.