Single focal length enlarging lens for medium format negatives....what effect?

[harlequin]

Dear APUG/PhotoRio Members,

I happen to shoot 645, 6x6, 6x7, 6x8 and on rare occasion 6x9 with old 1940's Bessa folder.

I know that there are hard and fast rules to follow.....

a) for 645/6x6 negatives a 75mm or 80mm would be optimum
b) for 6x7, 6x8 a 90mm or 105mm would be optimum
c) for 6x9 a 105-135 would be optimum.

My question is, I have a good quality 105mm lens, could I just use it for all formats, what would be
the effect, positive or negative. Luckily my print sizes are mostly 5x7 and 8x10, however in some
cases I will be using 11x14. This is not an attempt to be lazy. but some of my other focal length lenses
are not that sharp, 4 element designs, Prinz etc. I just want to use the best quality lens I have which is
the 105. Other than getting a smaller print or having to raise the enlarger head, is there any detriment
to using a 105 on a 645, or 6x6 negative??.

MANY MANY Thanks for your feedback on this.
I just want the highest quality possible.

Harlequin

 

[DWThomas]

I'd say mostly the limitation is the maximum enlargement you can make using a long focal length on a smaller format will be smaller than with the optimum lens.

 

[tedr1]

I agree, the reason to use different focal lengths is "mechanical" rather than "optical" it is simply a matter of the degree of enlargement available from the limited height of the enlarger column with the head raised to the top. A shorter lens will give a bigger enlargement.

Note that the opposite does not apply. A shorter lens should not be used with larger negatives because not all the negative will be projected, the corners will be lost.

 

[MattKing]

Enlarging lenses are optimized for a range of magnifications, so the possibility exists that using the 105mm lens for a large enlargement from 6x4.5 may take the lens outside its optimized range.
For smaller enlargements? I use my 105mm lens to do postcard prints from all sorts of formats.

 

[Rick A]

I own the perfect solution, I use my Wollensak 90 mm for all medium format sizes, 6x4.5 through 6x9. This lens was designed for 6x9 format, and serves duty for all smaller formats, my go to for small 35 mm prints.

 

[David A. Goldfarb]

Thread title updated to specify "enlarging" lenses for "medium" format, since we're mainly talking about rollfilm here, and people tend not to notice what forum the question is in, if they happen to see it in the "new posts" view.

As to the original post, unless I need to print big, I tend to leave a 150mm lens on the enlarger most of the time for 4x5" and medium formats, since I wouldn't gain much, if anything, by changing to a smaller lens.

Potential concerns might be going outside the optimum range of magnification, as mentioned above, or inviting column vibration issues by having the head further up the column with a longer than necessary lens. If you don't already own a longer lens, then cost might be an issue since longer enlarging lenses tend to be more expensive than shorter lenses of the same quality, but if the lens is paid for, then it's paid for.

 

[M Carter]

The EL-Nikkor 80mm 5.6 will cover 6x7 nicely - sometimes overlooked in the "which lens per format" discussions.

I've gotten to where I start with 4x5 prints (8x10 cut in quarters) or something like 5x6 (chopped up 11x14) - I sort of get to know the neg at the smaller size, usually with MGWT fiber. My final prints are all lith prints, so I move on to lith as it's much more palatable to get 4 or 5 test prints from some discontinued paper - lith being such an oddball situation, I like dialing in exposure and burning, etc. Then I do the exposure math and go to 11x14, 16x20, whatever.

Problem with that and an 80 or 90mm lens - the damn easel bangs into the lens stage. I'll probably get out my 135 next time... I assume a 4x5 print at F16 on a 135mm with 11" lens stage height can be translated to an 11x14 at 22" with an 80mm lens with the same math.

 

[Ron789]

A 105mm lens will serve you perfectly well. There may be limitations regarding the maximum enlargement you can achieve. A benefit is that you're using only the center of the image circle when enlarging smaller (6x4.5, 6x6) negatives and that gives the best image quality and even light spread.

 

[faberryman]

I just want to use the best quality lens I have which is the 105. Other than getting a smaller print or having to raise the enlarger head, is there any detriment to using a 105 on a 645, or 6x6 negative?

No.

 

[Maris]

.....As to the original post, unless I need to print big, I tend to leave a 150mm lens on the enlarger most of the time for 4x5" and medium formats, since I wouldn't gain much, if anything, by changing to a smaller lens....

The one longer lens is a good idea. I use a 135mm for 6x6, 6x7, 6x8 negatives. For modest enlargements, say 8x10, the lens' resolving power is not challenged and enlargement ratio optimisation is basically irrelevant. Moreover the longer lens has a bigger optical field and the small negative uses the best part of it - the middle. And the enlarger height is comfortable. I can easily get my head under the lens to use a grain magnifier and the negative carrier goes in at about eye level; very convenient.