Odd higher density marks on RA-4 print; probably an optical issue.

[BobNewYork]

Is the 45mm lens tight when it's mounted? Maybe the darkslide is warped? I hate these intermittent problems - you can't find anything to fix and you live in fear of them !! No better than cars !!!

Bob H

[Tom Kershaw]

Bob, yes it is irritating, and means I can't use the camera for serious work until I've got it figured out.

Here's a link to info on the RF645: http://photo.net/equipment/bronica/rf645

Tom

[BobNewYork]

I just looked at the contact sheet again, (would love to post it - but I can't scan for the time being) and the light definitely changed. In my case I took four frames in relatively quick succession with the camera tripod-mounted and with the same lens. The difference in the frames was two with and two without a G2 filter and an exposure variation of 2/3 stop for each of the two "sets". The mark shows on one filtered and one unfiltered frame but it's clear that the light changed. (It was in the U.K. !) The more I look at it, the only thing I can conceive is a freak reflection into the lens from something. I was using the 100mm macro so I'll get that out later and see if I can see any bare metal on any part at the front. I also tend to stand right up next to the camera when it's tripod-mounted, so it could have been something I was wearing!

Many years ago I had a similar incident with a different outfit. It stopped me trusting the camera for a long time, though I did use it - and it never happened again. I'm not going that route again though. I'll just keep using the system.........until it comes back to bite me in the arse!

Bob H

[Tom Kershaw]

Interesting story Bob, but this problem seems more continuos, at least for the time being.

Tom

[Tom Kershaw]

Now that I've printed the same negatives with the DeVere 5108 enlarger & Rodenstock Rodagon 150mm f/5.6 lens without finding these marks, it seems as though the problem is with the other lens, the Schneider Componon-S 80mm f/4.

Tom

[BobNewYork]

Wow - I'd never have gone there Tom! Glad it's sorted though - you can take photographs with your mind at ease!!!

Bob H

[Tom Kershaw]

Well Bob, the plot thickens, I'm now not so sure it is the lens...

See this:


The scratches line up with the density marks seen in prints. In the Meopta Magnifax the metal lens carrier sits close to the the diffuser so it is entirely possibly that I have bashed the carrier up against the plastic on multiple occasions.

Tom

[BobNewYork]

Looks like you've found the culprit Tom. The fact that you didn't notice this on other negs may be due to the fact that the marks "lined up" with higher density portions of those negatives. I wonder if the black marks are residual paint from the negative carrier. The scratches probably wouldn't be a big problem if they didn't have density. Perhaps that could be cleaned out. Alternatively you should be able to replace the diffusion material. I don't know if Meopta sells this part - and even if they don't, some other neutral diffusion material should work. The alternative, of course, is to take only photographs with highlights in those exact areas. Guess not!

Seeing the Meopta takes me back. I used to sell Meopta enlargers at my Dad's shop back in the sixties and seventies in Surrey. ( Aahh - the "Good Old Days" - back when men were men and wore floral shirts and bell-bottomed jeans )

Post how it works out Tom. Good luck mate.

Bob H

[Tom Kershaw]

Bob,

Thankfully I have a spare and RK Photographic still sells spare parts.

Tom