Which enlarging lenses should I keep?

[Bob Salomon]

Bob, I agree. This is a recipe that doesn't fail.

Anyway optimal aperture of the enlarging lens "IS 2 TO 3 STOPS DOWN FROM WIDE OPEN!", but it also can be 1 to 2 stops, and some lenses like Rodagon N also performs quite well fully open if aligment is perfect...

But that 1 to 3 stops down still allows for adjusting fall off of a relatively short enlarging lens.




In this point I disagree a bit, I agree that in regular conditions we should have no more than 1/3 fall off, and because that a 135mm enlarging lens is not desired for regular 4x5 work, so we may prefer 150mm or 180mm...

but... what happens if we have a 45 negative that was exposed with fall off and then we have thinner edges ? the fall off from a 135mm enlarging lens is to help us !!! doesn't it ? don't we want less light in the corners?

Pere, first, only lenses like a Rodagon G mural printing lens is going to perform optimally close to or at wide open. All others require 2 to 3 stops down.
Next, when you use a lens longer then recommended by the lens manufacturer you can not obtain optimal results. A modern, high performance, enlarging lens recommended for a particular format will always outperform a similar quality lens for prints within the optimal enlargement range. In fact, the 120 Rodagon WA will out perform any other focal length within its optimal magnification range save for extremely high end lenses like an Apo Rodagon N.

You are simply spreading old wive’s tales based on much older lens technology and, possibly, not maintaining proper enlarging requirements!

[Leszek Vogt]

Bob, and without disagreeing with you, the essential ingredient/s is the operator/printer who understands how all of these details intertwine-dovetail. Sure, good equipment helps the cause.

Les

[Drew Wiley]

Ideally, one grinds the diffuser below the mixing chamber (and above the neg carrier) to match the falloff of a specific lens. But since falloff can differs at different f-stops with the same lens, and the fact that multiple lenses might be used, is a good argument for having a set of interchangeable diffusers. Edge and corner burning is sufficient for lots of ordinary black and white purposes, but not so good for certain serial exposure applications. But in the real world, I think Bob's advice of never using a longer than brochure-normal enlarging lens is sheer nonsense. I do it all the time for the most demanding applications. For example, my 240 Apo Nikkor will outperform any 150 enlarging lens, including my superb 150 Apo Rodagon. Yes, there's an f-stop penalty or speed penalty, so I use both, as well as a more conventional 180 Rodagon. And everyone knows the 210 Apo EL Nikkor is the gold standard, though very costly and too heavy for many enlargers.

[Bob Salomon]

Ideally, one grinds the diffuser below the mixing chamber (and above the neg carrier) to match the falloff of a specific lens. But since falloff can differs at different f-stops with the same lens, and the fact that multiple lenses might be used, is a good argument for having a set of interchangeable diffusers. Edge and corner burning is sufficient for lots of ordinary black and white purposes, but not so good for certain serial exposure applications. But in the real world,
I think Bob's advice of never using a longer than brochure-normal enlarging lens is sheer nonsense. I do it all the time for the most demanding applications.

Drew, to each his own, but it is still an old wive’s tale with modern, high end lenses.

I have been involved with numerous high end labs and studios and have seen the critical tests between focal lengths at center edge and corners, longer then recommended focal lengths result in less then the optimal results!

[Drew Wiley]

The proof is in the pudding. And my personal standards are higher than any "high-end lab" I've ever encountered. Home cookin' gives one that luxury. I'm not on the clock. But some of the differences between lenses are not worth arguing about.
Nobody will notice in the final print. Distinctions can be seen under a Peak Critical magnifier, esp at the corners of the field.
And for highly nitpicky applications like precision dupes or internegs, the qualitative differences can be significant, esp given
the fact that this often adds up due to multiple steps being involved, including masking registration. Don't panic, Bob, I've been using Apo-Rodagon N's most of the summer, and strongly endorse them.

[Bob Salomon]

The proof is in the pudding. And my personal standards are higher than any "high-end lab" I've ever encountered. Home cookin' gives one that luxury. I'm not on the clock. But some of the differences between lenses are not worth arguing about.
Nobody will notice in the final print. Distinctions can be seen under a Peak Critical magnifier, esp at the corners of the field.
And for highly nitpicky applications like precision dupes or internegs, the qualitative differences can be significant, esp given
the fact that this often adds up due to multiple steps being involved, including masking registration. Don't panic, Bob, I've been using Apo-Rodagon N's most of the summer, and strongly endorse them.

Drew, glad to hear that but I can guarantee you that I have been involved with labs with standards beyond yours!

[faberryman]

Drew, glad to hear that but I can guarantee you that I have been involved with labs with standards beyond yours!

Grab the popcorn as the duel develops over whose standards are the highest.

[interneg]

Grab the popcorn as the duel develops over whose standards are the highest.

I wonder how much of it would survive double blind testing...

[Bob Salomon]

I wonder how much of it would survive double blind testing...

It’s been done many times by many labs, studios and government and industrial entities.

[Drew Wiley]

Popcorn time. No fake butter please. Name one lab on the West Coast. I probably knew the owner as well as his equipment and methods. And like I said, what commercial lab ever had the time and budget to do go to that kind of fuss? Even the biggest dye transfer lab in NYC cut corners. And I'm 100% certain you've never even heard of the best equipped lab in this hi-tech area because they were never open to the general public. But their minimum charge of $40,000 pretty much ruled that out. They could certainly many do things alt-wise that I cannot, but it had little to do with optical enlarging. The second best equipped lab you probably never heard of either because the clients were mainly overseas corporations, and it had stunning optical equipment, but not quite like mine. Nor did even they go to extra steps of control dupes etc. Just retired. And frankly, you've never seen my own work, so whether it's great or simply horrible, you'd can't honestly state. And double blind? Does that mean only Rodenstock enlarging-marketed lenses against only similarly marketed lenses, with all the
graphics application ones left out? Even the big labs staked their income on having more options than that. Think I'll grab some popcorn myself and see what follows ...