Re-assembling RB67 Focusing Screen

[Kevin Harding]

Hi everyone,

My RB67 focusing screen got rather humid in a rainstorm recently (water between the clear glass and the fresnel portion) so I disassembled it to let it dry out.

Idiotically, I didn't note which direction the fresnel part should go back into the RB67 - facing 'up' through the WLF, or 'down' towards the mirror.

I have a plain RB67 focusing screen, with dashed lines on either side to indicate portrait orientation. No split-screen or anything.

Your advice is much appreciated, as I'm concerned now about critical focus being off.

 

[Kevin Harding]

dull side down

Thanks. I'll be a little bit more clear, in case I wasn't, and you can tell me if I'm wrong, again : )

The focusing screen has two pieces of glass. One is clear with the dashed marks for portrait alignment. Another is fresnel-engraved on one side, and what appears to be slightly frosted on the other.

When you say dull side down, should it go (WLF) -> clear glass -> fresnel/frosted -> mirror OR (WLF) -> clear glass -> frosted/fresnel -> mirror ?

Thanks!

 

[Kevin Harding]

Thanks!

 

[Kevin Harding]

Thanks again. I was just looking through some images I shot over the week and it seems to be back-focused by about a foot or two.

However, I was using my 65mm lens which has a floating element, and I may have been standing closer to the subject than infinity, which may be the root cause of the issue.