Enlarger lens question

[Anne Williams]

I have a Beseler 45MCRX enlarger and a Schneider Componon-S 150mm lens. I am unable to print 16x20 on the baseboard with it. I have found a used Rodenstock 135 lens and a Rodenstock 120 WA for twice the price of the 135. How large would I be able to print 4x5 on the baseboard with the 120mm lens?

Thanks for your help

[Nick_3536]

Something doesn't sound right. 16x20 shouldn't be an issue I think. Unless you're cropping alot. Beseler claims 20x25 with the current 4x5 model [45 MXT]

[Anne Williams]

I am a novice, so I may not be doing things correctly, but with the enlarger head as high as it will go, the top bellows set to 4x5, the 150mm lens, and without cropping I am only able to get something about like a 15 x 19 print size once I've focused it. This is an old enlarger, so the newer ones may go higher.

[Mark_3899]

with a 135mm lens on that enlarger you will be able to print 20x24 from a 4x5 neg on the baseboard.

[Gem Singer]

Hi Anne,

A 135mm enlarging lens would probably be the best choice for making 16X20 prints. It will allow a more comfortable reach distance from the focusing scope on the easel/ baseboard to the focusing knob on the enlarger. A 120 WA would be even better, but it's not necessary to make the increased investment, unless you are planning on making a lot of prints larger than 16X20.

Midwest Photo has several used 135's listed on their website. The prices are reasonable The Rodenstock Rodagon's are excellent lenses, as are the Nikkor 135's.

[Michael S. Briggs]

Measure the maximum distance D between the film and the print on the baseboard. Don't forget to include the easel in the measurement. Define the symbol alpha = D / f, where f is the focal length of the lens (be sure to use the same units for D and f). The maximum possible magnification m is

m = 0.5 * (alpha - 2 + squareroot [alpha*alpha - 4 * alpha] )

(If someone wants to be excessively accurate, D should be corrected for the separation of the principal planes of the lens.)

[Anne Williams]

Thanks for your help. I'll go with the 135 since my darkroom isn't big enough to want to tackle much more than 16x20.

[J. P. Mose]

Anne,

I have the same enlarger and a 150mm. I bought a Beseler Adjust-a-stand or table off Ebay a couple of years ago. The enlarger fits perfectly on the table and the wood base is adjusted up and down on various racks (similar to an oven). The usually sell for around $100 - $125 and really give you more ability to enlarge and crop.

JP Mose

[Leonard Evens]

Michael's formula is correct, but the following might be easier to use if you actually have the lens. Raise the head to its maximum height and focus on the easel. Measure the distance from the lens board to the easel, divide that by the focal length of the enlarging lens, and then subtract one. That is the magnification. You need a bit over four in order to produce a 16 x 20 print from a 4 x 5 (actually about 95 x 120 mm) negative. (This method also ignores the separation of the principal planes.)

Of course, his method doesn't require having the lens if we assume the lens moves and the film plane is fixed, as is usually the case.

[John D Gerndt]

There are lots of 135mm lenses out there and many for cheap. Maybe you could even borrow one and check things out. At 4x enlargement a regualr Componon would be fine or any 6 element lens for that matter. If you are handy then you can build a stand with a drop-base or mount the enlarger to the wall. A 120mm seems like too far to go to get a normal size print.

Cheers,