medium format enlargment question

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A Question... I have been printing from 35mm negatives with my Beseler 23C II enlarger and 50mm lens with no problem. I have recently attempted to print from medium format (120) negatives. I have the proper negative carrier for this size, but have found that the light does not extend to the full size of the negative- I see only a round area of light- the corners of the projected image are dark. Do I need a different lens to work with a larger negative, or is there another adjustment I'm missing? Any help to a medium format novice would be greatly appreciated. Thanks, Karen

-- Karen Jenkins (rabbit5@azstarnet.com), March 17, 1998

Answers

If you are getting a circular image, you need to positon the top of the enlarger to the proper setting. On the right hand side of the head is a knob that moves the top of the head up and down. It should have markings, running vertically along the side of the head, for the appropriate negative sizes from 35mm to 2 1/4 by 2 3/4. Just lower the head to the appropriate setting. If the scale is gone, all the way up is for 35mm and all the way down is for 2 1/4 by 2 3/4. In addition a 50 mm lens will project a large image, with possible light fall off to the corners. You should probably look into a lens in the 75 mm to 90mm range for medium format.

-- Marv Thompson (mthompson@clinton.net), March 17, 1998.

Karen: I know of no 50mm enlarging lens (there may be a very expensive one out there) that will cover a 6x6cm neg. So, yes, you will need a different lens to work with bigger negs than 35mm. As suggested, something in the 75mm to 80mm range for 6x6, or 90mm to 105mm for 6x7 negs. Frank

-- Frank Armstrong (elf@ntr.net), March 18, 1998.

Similar question

I have a 75 mm lens. Is it fine for printing 35 mm film as well as some medium format work?

thanks, david

-- David Parmet (dparmet@interport.net), April 14, 1998.


Using a 75mm lens for 35mm negs should be fine, but may not give as good quality as a top-notch lens designed for the format. Do make sure the negative is masked-down, so light doesn't escape around the edges to cause flare.

-- Alan Gibson (gibson.al@mail.dec.com), April 16, 1998.

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