HELP! Enlarger problem

[happusa]

We are trying to print 4x5 negs on a Beseler enlarger. The problem is the projected image has a very bright center and darkens to the edges. We have set the enlarger to the 4x5 setting, checked the condensers for proper position. No matter what we tweek or turn the result is the same. I don't know the model # but the enlarger has a motorized focus and adjustable voltage control for the light. We are using a 75mm lens.

Any insight to what the problem may be will be greatly appreciated.

 

[Jon Shiu]

Hi, you need to use a 135mm or 150mm lens to cover 4x5.

 

[happusa]

Duh, how could we not think of something so simple. Thanks Jon.

 

[dr bob]

Duh, how could we not think of something so simple. Thanks Jon.

A 150mm is good for 4x5. And, don’t feel bad. Once upon a time, when I first mounted my “new” 150 mm on an appropriate cone and attached the assembly to the enlarger (the Omegas have a “push up and turn 90 degree” mount), I was horrified that nothing would bring the image into focus or even cover an 8x10 paper. In panic mode, I removed the cone intending to have the “damaged” lens replaced by the vendor, when I noticed that in my haste, I had forgotten to remove an 80mm lens previously used for some 6x6 enlargements.