The Schneider QC was 40+ years ago, anything could have happened since. Even when new you will still get some lens that barely make it past QC, most that breeze through and some that are exceptional. If that variability didn't exist then there would be no need for QC.Originally Posted by Drew Wiley
John, same surprise here. I tested my late Componon-S 180 time ago and found it to have what I think is a quite pronounced field curvature. It is a sharp lens but needs to be stopped down to get sharpest corners on 5x7", f16 is not enough. Cannot remember... I think I got similar results as you making comparisons with my Rodenstock f9 process lenses (I have a Schneider G-Claron 150 as well). At the end, I use the Componon-S on the enlarger, I find it to be more convenient.
Think about the real sharpness you need for a given print size. Sometimes the focusing loupe on the easel is more capable than your naked eyes on the print.
Oh I see; this was for an enlargement. Interesting.
I see that the G-Claron's aperture was f22, although the Componon's aperture wasn't that far off.
Don't know about G-Clarons, but the ideal aperture for Rodenstock process lenses is f22. If the same is true for G-Clarons, that might help explain what you're seeing.
Yep...the G-Claron is also calibrated for f/22 - which works great because the Heiland LED head I'm using is so, so bright that, even powered down and projecting a "gutsy" negative to 30x40 (which is why I purchased this lens in the first place), my times (split-grade totals) are still running well under a minute. With the 180 Companon-S stopped down to its ideal of F-11/16, my times are often too short and I need to use an ND filter to keep the aperture where I want it. Do keep in mind that the above generally applies when I'm using Ilford Classic - which is so very fast (too fast - anyone else share this view?), and other papers are a bit more reasonable in this regard.
Then again (trying to be fair to the Companon)...the negative plane on my Zone VI might be just a hair off, so the extra depth of the Claron at f/22 might be skewing my observations. Don't think so though as I spent a huge amount of time calibrating the system.
Neil I'd be curious how the 180 Apo-R fares! I know you and I have one; my 150 G-C which I bought new has developed some coating issues, so I don't think it's usable. L
According to historic Goerz literature, f9 APO Artars were optimize at f16, smaller full aperture APO Artars were optimized at f22.
Majority of process lenses work well from f16 to f32, f9 APO Artars are pretty good at f11.
To achieve reasonable print exposure times (say 30 seconds) at f22, means significant light output from the enlarger light source.
Bernice
All my Apo Nikkors conspicuously excel any official enlarging lenses I own, including my Apo Rodagon N's. The latter have more speed, however.
Incidentally, all these Apo Nikkors excel at f/11 onward. It's a myth that they are optimized at f/22 for purposes like this. Dot reproduction for pre-press color separation purposes is a different topic.
FWIW, I found the Componon-S 180 to be "better" on 5x7" at f22... at f11 is far from "ideal", that is, way soft at the corners (at least on my unit).
Almost all current papers are too fast to my taste and printing sizes; this is the reason I made my own light sources, with different output power depending on the negative and magnification.
Are you using a glass carrier, properly aligned? But Componon S isn't in the same league as apo process lenses anyway.
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