Enlarger focussing issues

[esc_ctrl]

I am using a Kaiser VPM6002 enlarger with a Rodenstock 50mm lens and have the following problem:
when printing larger sizes (above 18x24) I have to turn the focusing knob all the way up until it stops and the bellows is completely collapsed. I can't get it 100% in focus then. There is always a little tad missing.
18x24 and below is no problem, there is still a little leeway upwards and I can focus properly.
Anybody know what the problem could be?

 

[Dayrell bishop]

I have a meota and it has a lens holder that can be used concave or convex , when used concave the bellows do not have to be compressed so much , I think this is what you may need . Or you may be able to turn your lens holder upside down.

 

[Dwig]

Perhaps the lens is mounted incorrectly. There is a ring that needs to be in one orientation for 50mm lenses and another for 75mm lenses. See page 7 in the manual:

http://www.kaiser-fototechnik.de/pdf/anleitungen/4420_3_en.pdf

 

[Bill Clark]

Thought I would mention, I have two lenses. One is for 35mm negatives and the other for medium format negatives. If I try to use the medium format lens with 35mm negatives, I need to move the head way up just for an 8x10 print and I hsve focusing issues. I use an Omega B-22 XL.

I'm not in my darkroom. I can go take a look at the lenses to give you specifics if you need the information.

 

[Bill Clark]

I have a 75 f3.5 and a 50 f3.5 for my enlarger.

 

[Ronald M]

There is probably a recessed lens board for 50 mm lenses. You might have to make one.

Lens longer than 50 will require greater focus distance given the same size print . A bigger neg will equalize the distance partially

 

[ChrisN]

Printing 18 x 24 = probably a medium format negative. Bill Clark is on the right track. You'll need a 75mm or 80mm lens for 6x6 negs.

 

[esc_ctrl]

Thanks for the hints! I will have a look at the lens mount and see!
I am talking about 35mm. For 6x6 I have a 90mm lens. No issues there.
I will keep you informed

 

[skibeerr]

+1 on the recessed lens mount.

 

[esc_ctrl]

Like Dwig said, I just had to flip the ring. Works fine, thanks a lot!