What lens do I need to enlarge 6x6 to 16x20 on a Beseler 45M

lloyd darkrooms · Apr 20, 2015

Hello APUG, In my black and white darkroom I am working with a Beseler 45M. I currently have three lenses on hand: 50mm, 75mm, 135mm. When I attempt to enlarge my 6x6 negatives to 16x20 with the 75mm lens, there is a strong vignette surrounding the image. No matter how I adjust the bellows, I cannot successfully print without a vignette across all four corners. If I use the 50mm, the vignette is worse. With the 135mm, I cannot enlarge a 6x6 to 16x20. What focal length lens do I need? Thank you - Lloyd

gone · Apr 21, 2015

Maybe I'm just plain dumb, but how do you make a rectangular print from a square negative? You're asking how do you get a 20x20 print from a 6x6 neg, then crop? If that's the case, then you need something that will cover at least 20x20. I'm not sure that enlarger will make a print that large w/ any lens w/o moving the baseboard down somehow, or flipping the enlarger to project onto a wall or something. In any case, here's the manual for that enlarger. Great piece of equipment by the way. Wish I had one.

http://www.jollinger.com/photo/cam-coll/manuals/enlargers/beseler/Beseler_45M.pdf

Rick A · Apr 21, 2015

The chosen lens most likely doesn't cover 6x6 then. You will need an 80mm or 90mm lens to cover the format. A 75mm enlarging lens generally will cover 6x4.5. You may also need a column that is taller.
Momus, to make a rectangular print using a square negative is as simple as using rectangular paper and cropping.

gzinsel · Apr 21, 2015

I think its the placement of the condenser lenses, your 75mm will cover. for 16x16 or 20x 20 from a 2 1/4.

darkosaric · Apr 21, 2015

I have used 75mm f4 el nikkor for 6x6 - it works fine. As other stated: it is probably the condenser lens.

fotch · Apr 21, 2015

Welcome to APUG. Check your condenser height.

ParkerSmithPhoto · Apr 21, 2015

lloyd darkrooms said:
Hello APUG, In my black and white darkroom I am working with a Beseler 45M. I currently have three lenses on hand: 50mm, 75mm, 135mm. When I attempt to enlarge my 6x6 negatives to 16x20 with the 75mm lens, there is a strong vignette surrounding the image. No matter how I adjust the bellows, I cannot successfully print without a vignette across all four corners. If I use the 50mm, the vignette is worse. With the 135mm, I cannot enlarge a 6x6 to 16x20. What focal length lens do I need? Thank you - Lloyd

Lloyd, as others have mentioned, the condenser is probably the culprit here, and they can be a nightmare to deal with.

Try setting the condenser to the correct height, and using the 75mm lens and the 6x6 carrier, expose a sheet of paper to about a medium gray. You will most likely see unevenness in the print, often as much as 1/2 stop off in the corners.

If that's the case, I will try to post my super simple LED conversion technique.

480sparky · Apr 21, 2015

I can get 14" with a 100mm lens, and 24" with a 50.

lloyd darkrooms · Apr 30, 2015

after looking at the manual, I believe item #5 the heat absorbing glass is improperly positioned. Currently it is placed directly ontop of #10 condenser top 7 1/8.

lloyd darkrooms · Apr 30, 2015

after removing the heat absorbing glass I am still getting two concentric circles and uneven distribution of light even without a lens.

lloyd darkrooms · Apr 30, 2015

I will share an image of my condenser and how it is currently assembled.

dynachrome · Apr 30, 2015

If I needed a larger print from 6X6 I would probably use a 60/4 Bogen Wide Angle enlarging lens and close down to f/8.

Sirius Glass · Apr 30, 2015

A 80mm to 90mm lens is needed; a 75mm lens may not be able to do the enlargement.

nworth · Apr 30, 2015

A 75 mm lens generally covers a 6X6 negative; a 50 mm will cut off the corners and a 135 will require you to raise the enlarging head too far (about 58 inches).

Old-N-Feeble · May 1, 2015

dynachrome said:
If I needed a larger print from 6X6 I would probably use a 60/4 Bogen Wide Angle enlarging lens and close down to f/8.

I think I may have one of those somewhere around here.

lloyd darkrooms · May 1, 2015

Dennis S · May 1, 2015

The chipped glass is probably the culprit. You can either try painting the chipped area in flat black paint may work but replacement should clear up your enlarger problem. Small things can cause enormous problems.

msage · May 1, 2015

I use the Nikkor 75mm to 16x20 from 6x6 negs all the time.
Two thoughts.
Is the condenser put together correctly? Going by memory, the curved surfaces face each other with the spacer between them. The slot in the spacer aligns with the filter drawer.
Or the condenser is too high, the top knob controls the height. There is a guide to set the condenser that is often missing.

See this http://www.beselerphoto.com/parts-pdf/condenserheadview.pdf

lloyd darkrooms · May 1, 2015

lloyd darkrooms · May 1, 2015

lloyd darkrooms · May 1, 2015

lloyd darkrooms · May 1, 2015

i think i fixed it. i am having trouble uploading the photos. it is the motorized model....hold on and i will try to upload a full image. when I extend the top condenser bellows I believe my issue is resolved...

lloyd darkrooms · May 1, 2015

lloyd darkrooms · May 1, 2015

when the bellows are too high i get the vignette...when i adjust them the results are the image i shared above

lloyd darkrooms · May 1, 2015

lloyd darkrooms said:

the cone of light covers the entire negative! as you can see my 6x6 negative is in a 4x5 carrier. thank you for your help I believe my problem has been resolved. If I attempt to enlarge the 6x6 and crop it to fill out the entire 16x20 paper I do not have a vignette. the problem was with the condenser bellows being at the incorrect height. as you can see my unit is missing the gauge that tells you the correct heights...must have broken off.

What lens do I need to enlarge 6x6 to 16x20 on a Beseler 45M

lloyd darkrooms

gone

Rick A

gzinsel

darkosaric

fotch

ParkerSmithPhoto

480sparky

lloyd darkrooms

lloyd darkrooms

lloyd darkrooms

dynachrome

Sirius Glass

nworth

Old-N-Feeble

lloyd darkrooms

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msage

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What lens do I need to enlarge 6x6 to 16x20 on a Beseler 45M

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