Choosing between 135mm and 150mm lenses for printing 4x5 negatives

[Rory_3532]

In order to choose between these focal lengths, I want to determine what the difference will be in reproduction ratio/print size for a given lens-to-paper distance. On an enlarger that I just bought, the maximum column height, taking into account the height of my ceiling and the maximum drop of the baseboard (it's a floor standing enlarger that allows adjustment of the baseboard height), will be about 7 feet. Of course, the height of the enlarger head, etc. will reduce this. Can someone tell me what the formula is for determining print size for a given lens-to-paper distance?

Are there other considerations in choosing between 135mm and 150mm and, if so, what are they?

Finally, recognising that this has been discussed before, and rather inconclusively, I would appreciate any comments about choosing between an Apo and non-Apo lens, especially in relation to black and white printing.

[Bill_1856]

Quit obsessing over trivia. It doesn't matter.

[jnantz]

rory -

i can't answer any of your questions, but i have both a 135 (older schneider, chrome barrel) and a 150 (g-claron) that i use for enlarging 4x5 film. i used to use the 135 because the enlargement distance was smaller, now i use the 150 because i realized that the extra distance from lens to paper wasn't really enough to worry about.

good luck!

- john

[jose angel]

After hours comparing Apo and non Apo enlarging lenses literature and comments, I have found that is near impossible to know the -real- differences -in practice- between them. The only way to know it is to have side by side both versions, and compare this units. Even is well known that could have little differences between units from the same lenses, owing to their assembly.

Some people said that there is no difference, others that the difference is subtle in big enlargements, others that is clearly visible... The same about the differences between Rodenstocks and Schneiders.

All the charts given by manufacturers are theoretical, only "illustrative".

The Ctein`s "Post Exposure" gives you some clarifying ideas about enlarging lenses. He said that the best enlarging lenses are not necessary the most expensive, and curiously, the Apo most known versions doesn´t have that expected apochromatic correction...

If the lens belong to the 6 or 7 elements "top class" group of lenses, I wouldn´t worry so much about Apo or not; some of them are better in terms of contrast, others in color correction or distortion, light fall off... the perfect lens doesn´t exist. Probably, an Apo lens will work better with color enlargements, but I find in the manufacturers literature higher performance in other aspects in the non Apo versions (and, What about b/w VC filtering? I don`t know...)

In my opinion, if you are concerned about the expense, this small difference could not be worth the money you have to pay for it; if money is not an issue, buy Apo, because it must be the best.

[jose angel]

The issue is to have a Versalab Parallel laser alignment gauge. If you does`n have one of this devices, and if you are really concerned about sharpness from side to side in your prints, you must consider to buy one...

[Michael S. Briggs]

The formulas relating object distance (film to lens for an enlarger), image distance (lens to print for an enlarger) and magnification (print size divided by film size) are given in the Lens Tutorial at http://www.photo.net/learn/optics/lensTutorial.
For a similar question several days ago I gave the related equation that gives the maximum magnification based on the maximum possible distance from the film to the print: http://www.largeformatphotography.in...ic/498804.html.





You can get the exact answers using the equations, but the easy answer is that you should be able, using a floor standing enlarger, to make very large prints with either lens. Supposing that you can get a distance of 5 feet (1524 mm) between the film and print, the equation that I gave shows that you will be able to make an 8X enlargement using a 150 mm len.





My recommendation is to get a modern 6-element 150 mm lens. Besides the differences in max possible print size, another consideration is that a shorter enlarging lens will have more illumination falloff away from the center of the print.

[David A. Goldfarb]

If you've got 7 feet of column, that's plenty, so you might as well go with the 150 for slightly better coverage, and the fact that they are more commonly available.

Any modern 6-element lens will be more than adequate, but I've found that I could see a difference even in small enlargements when upgrading to apo lenses. Darkroom equipment is relatively cheap these days, so if you can find a used Apo-Componon or Apo-Rodagon for $300-400 in good condition, it's probably a good deal.

Apo lenses are just as useful for B&W as for color. What appears as color fringing with a poorly corrected lens in color may appear as fuzziness or focus shift in B&W. Apo lenses are also better corrected at wider apertures, which is handy for big prints and for production printing where you might want shorter exposure times. I would say, though, if you print exclusively with VC paper, where you are always using a strong monochromatic filter and you are focusing with the filter in place, then there is less reason to use an apo lens.

Links to the formulas have been posted above, but if you want a calculator for such things, do a Google search for "f/calc." The Field of View calculation can be used to determine enlargement size by substituting the film-to-paper distance for the film-to-subject distance.

[Rory_3532]

Thanks very much. Having now done a few calculations at various reproduction ratios, it's clear that the difference between 135mm and 150mm, given the available column height, will not be significant. Even for quite big enlargements, it seems to be a matter of a few inches. I'll go with a 150. Not sure yet whether it will be apo. For the difference in cost between an apo and non-apo lens, I could buy a Versalab alignment gauge.

[David Karp]

I second the recommendation of Ctein's "Post Exposure" and his discussion of enlarging lenses. If my recollection is correct, he says that there was only one true APO enlarging lens, and it is no longer produced. (Sorry, I don't have the book handy.) Ctein talks about 135mm and 150mm lenses that he tested from Nikon, Rodenstock, and Schneider. This chapter and the rest of the book are well worth the investment in time and money.

[John D Gerndt]

I'd agree that alignment is very important to sharpness. Nothing against Versalab but you could just as well borrow a 3 way laser level and put a paper or plastic target with a hole over it to do the same job. be sure to recheck the alignment once set and see how repeatable it is. This represents the limit of your ability to get perfect alignment. And dont forget to align the easles!

As to enlarging lenses I have played around with testing many lenses. Samples do vary. I have found quite a few surprises (one really fine Comparon <no, not Componon> and one dog of a Rodagon). I have noted a large price difference in going from the 135mm to the 150mm. Then again I have seem some first class 180mm and 210mm go for stupid little money. IMHO many lenses handle up to 4x (thats where that Comparon holds its own with an APO) quite well and after that you need a darn good one to get the best from a negative.

Cheers, Cheers,