Lens vignetting with beseler 45 w/dichro color head

[max_ebb]

I'm having a bit of a vignetting problem when printing full frame 6x7 negs. I saw the other thread about light fall off, but once I started reading it, I saw that it's a different problem.

I've had a few color enlargers, but this is my first 4x5 enlarger, and it's my first enlarger with an upper bellows between the film plane and the color head. With my previous saunders 67 enlarger, a 75mm nikor lens worked fairly well for 6x7 negs, but when printed absolute full frame, there was a slight amount of vignetting (barely discernible). With the beseler, I get major vignetting with the same lens with the upper bellows set anywhere in the medium format range. If I crank the film plane all the way up to 4x5 range, the vignetting isn't nearly as bad, but it seems a little worse than it was with my old saunders (I might be mistaken about that though).

I just got a 90mm lens, and it still has a bit of vignetting unless I crank the film plane all the way up to where it's closest to the color head (both lamps are working). I'm wondering if the upper bellows adjustment is strictly for using with a condenser head, and that I should just crank it all the way up when using the dichroic color head.

Anybody else using a beseler 45 (or any 4x5 enlarger with an upper bellows) with a dichroic color head? If so, where do you adjust your upper bellows for MF negs?

 

[Nick Zentena]

I'm half asleep but ya. The Beseler cone of light is for the condensor head.

 

[Nick Zentena]

Compress the upper area. Ignore the scale for setting the film format.

 

[glbeas]

Be sure your color head has the right light mixing box in it too. Some have boxes for smaller formats supposedly to increase the light output. The best all round is the full sized 4x5 box for every format, install it and forget it.

 

[max_ebb]

It has the 4x5 mixing box. I can print full frame 4x5 negs no problem with a 135mm lens (of course with 4x5, I had the film plane all the way up).

I'm sure it's just a matter of leaving the film plane all the way up (upper bellows completely compressed) for MF as well as 4x5. I didn't realize the upper adjustment is only for use with a condenser head.

Thanks for the responses.