Mamiya 135 3.5 N

I picked up this little gem from keh last week. Got an EX copy. Glass is flawless but the mount has some wear on it.

I was looking through the front element today while the lens was mounted on my 645 super. I noticed the rectangle on the rear element wasn't perfectly straight when it was mounted on the body. I tried to align it but the piece just fell out revealing the entire rear element.

What's the purpose of it this little piece and is it going to affect image quality if I don't have it? Thanks

It's probably to limit the light coming from the lens which is outside of the image area seen by the film from bouncing around inside the chamber, possibly reflecting back onto the film causing fogging.



Steve.