mamiya rb67 pro-sd back light seals

timk · Nov 3, 2009

Hi all,

I'm trying to diagnose a light leak problem, and I wanted to know what light seals there are on the Pro-sd 120 back.

The reason I'm asking is that the only foam light seal I can find on the back I have is the one for the dark slide (after unscrewing the cover).

Since I don't know the history of this back and I don't have another prosd back to compare it with, I wanted to find out if there *should* be any other light seals.

The pro back has about a dozen different light seals.. :confused:

Steve Smith · Nov 3, 2009

I don't think the Pro SD back uses foam. I think the previous backs do though.

Steve.

timk · Nov 3, 2009

thanks Steve, that's what I suspected, though it is good to know for sure!

John Koehrer · Nov 3, 2009

There are light traps in all four corners of the revolving back adapter.

Gadfly_71 · Nov 4, 2009

Mamiya got it right with the PRO SD backs, no foam seals. PRO S on the other hand are a mess. If you need a seal kit for PRO S do not use the kit from Aki Asahi. The seals for the rotating adapter do not fit on the side that faces the film back (the camera side is square, the film back side is rectangular). Jon Goodman ("interslice" on ebay) has the correct kit and is a truly stand-up guy.

Cheers,
Andrew

Steve Smith · Nov 4, 2009

Gadfly_71 said:
Jon Goodman ("interslice" on ebay) has the correct kit and is a truly stand-up guy.

Someone should buy him a chair!

Steve.

timk · Nov 4, 2009

I'm about 2/3 of the way through replacing the seals on my Pro back. It's ridiculous how many seals there are on this one.

I've been using the Jon Goodman kit and cutting them myself, so far I've resealed about 6 or 7 x 35mm bodies, the RB67 Pro body and RB67 Pro back with the same kit. Plenty more left in the kit still!

So, after burning through a few rolls of "shanghai 100" (my default cheap film for doing tests), I've worked out that I only get light leaks with the darkslide removed and the back on the body so I've ruled out most of the back seals. I've replaced the seals on both sides of the revolving back adapter and the dark slide seal on the back. Fingers crossed the next test I do reveals no more light leaks! What else is there that could cause leaks? I haven't done the seals around the mirror yet so that would be the next step if I have no luck with the next test.

John Koehrer · Nov 5, 2009

Do you have two long seals at the top & bottom of the revolving back adapter where the back mounts?

timk · Nov 5, 2009

yes, I have the 2 long seals on the back adapter which I have just replaced. I also have placed a seal on the other side according to the jon goodman instructions (this seal wasn't there on my rb adapter).

I've been going by the http://www.kyphoto.com/classics/seal/RB67_FilmBack.pdf instructions.

mamiya rb67 pro-sd back light seals

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