Beseler VC67 Vignettes 6x6 negatives

Some years back I bought one of these enlargers, and to be honest I haven't used it for several years after I started sc*nning film. I recently resurrected it to see if XP2 developed in black and white developers could be printed this way, and ran into a problem.
I was trying to print a 6x6 negative on a 10x8 sheet of paper, uncropped. This means the enlarger head is quite low to get the square image projected as a 8x8 square on the paper. I would get white vignetting at the corners. This was not present with 35mm negatives, and would go away with the 6x6 negs if I lifted the head as if printing on larger paper. The manual for the enlarger was lost long ago, and Beseler have not replied to my query. This is a diffuser rather than a condenser enlarger, and taking the side off the head didn't reveal any obvious problem. After I thought about it, I came to believe the problem is with the focusing bellows, which are maximally compressed when the head is low as for 6x6 on 10x8. I believe they are over-generously pleated, and as they fold as flat as they can go, the pleats intrude onto the light path.
Am I on the right track, or have I forgotten some setting that must be changed for MF negatives?

Chris

Hi Chris,
I'm not familiar with Beselers at all, but you don't say what lens you're using for your medium format negatives. Could you let us know which lenses you're using for each format as you don't mention changing lenses between negative sizes.

I'm using the 50mm/f3.5 that came with it. I was thinking that if the image circle thrown by the lens was too small, it should still vignette even when the head is raised, but if it is something as simple as using a longer lens that would be an easy fix!

Chris

Yup, there it is! You need at least a 75mm or 80mm lens for 6x6 negatives, up to a 105mm for 6x9. Basically, you need the "normal" lens focal length for each size. So, your 50mm enlarging lens is perfect for 35mm negatives but doesn't have the covering power for 6x6.

Hope that helps!
Sincerely,
Molli

Hi Chris,

An enlarger lens should be the about same FL as the normal taking lens for the format.

- Leigh

Thank you, I think.....I was trying not to spend more money!

C.

drmoss_ca said:

Thank you, I think.....I was trying not to spend more money!

C.

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I recently got the 80mm Nikkor EL for like $40 on eBay, great lens for up to 6x7. Yes, you'll have to spend, but not much, and you could probably find a Beseler or Omicron lens for even less.

I'm looking.....

Wollensak 90/4.5 on the way!

M Carter said:

I recently got the 80mm Nikkor EL for like $40 on eBay, great lens for up to 6x7. Yes, you'll have to spend, but not much, and you could probably find a Beseler or Omicron lens for even less.

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Because of this post I went to look at Schneider enlarging lenses on Ebay. They were always on my bucket list to get. Amazingly they're so cheap! I couldn't believe how low the prices were. Thanks.

nathantw said:

Because of this post I went to look at Schneider enlarging lenses on Ebay. They were always on my bucket list to get. Amazingly they're so cheap! I couldn't believe how low the prices were. Thanks.

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I know, I just got an absolutely mint 135mm Schneider for $40. It had an oddball thread size, but a step-down ring flipped over worked fine - I just have to file some spanner slots into it.