Rodenstock APO Rodagon N 50mm smallest aperture

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alexandru_voicu

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Hi everyone,

I have just bought and received an used APO Rodagon N 50mm lens and, while it generally appears in good shape, there is something that drew my attention. Namely, the aperture goes from 2.8 to f16 in what appear to be half stop increments only to stop before reaching the smallest aperture, f16. In other words, it stops at f13. To the owners of this lens that read this, I would be forever grateful if you can confirm whether this is normal or not. I bought the lens from ebay, the seller seemed like a genuinely nice person and I have to decide what I do.

Many thanks,
Alex
 
Maybe the stop for the working aperture is engaged? I have the non-APO version of this lens, so pls excuse if my advice is not appropriate.

Regards, Klaus
 
Hi and thank you so much for your help. Just a few comments. Of course I wouldn't use the lens at f16. However, if the lens is supposed to reach f16 but it doesn't, it means it has been tempered with or that the aperture ring mechanism is defective. Also, the lens behaves the same with the clickstops disengaged.

I just want to make sure the lens is fine.

Many thanks,
Alex
 
Well, I didn't mean the click stops but the configurable stop for the working aperture.
Turn the aperture dial and watch the f-stop scale. You will notice a small mark somewhere above the numbers. If I'm correct, the mark is set beteeen f/11 and f/16. Pull the aperture dial out by a few milimeters and turn it to set the mark to f/16. You will be able to turn the aperture dial all the way from f/2.8 to f/16 afterwards.
K
 
Hi Klaus,

Thank you so much, that solved the "problem". It's quite a relief. I wouldn't have figured it out without your help.

Now I have print with it. I have an El-Nikkor 50/2.8 and I want to see whether I detect any improvement.

Best,
Alex
 
alexandru_voicu said:
Now I have print with it. I have an El-Nikkor 50/2.8 and I want to see whether I detect any improvement.
Click to expand...

You *might*, but it will have to be at 11x14 or larger, perfect enlarger alignment and using a glass carrier, the EL-Nikkor is no slouch.

I own the 50mm 2.8, 80mm 4.0, 90mm 4.0 and 150mm 4.0 Apo-N enlarging lenses and they are no doubt regarded as the best in the biz. But they were also primarily designed and popularized with the reduction of color fringing in mind for Cibachrome, type R and type C color prints.

If you are just doing black and white then most good modern multi-coated enlarging lenses will more than satisfy. But yeah, the Apo-N's are really all anyone will ever need and they deserve the reputation they get.
 
I agree with what KM-25 says. The APO lenses are designed for color and that's where the difference will be noticed. With B+W the Nikkor will be equally as good. And what KM-25 mentions about keeping everything perfectly flat and parallel is vitally important (glass carrier, perfect alignment; even using a vacuum easel.)
 
I have made some test on 40x50cm in B&W for the Rodagon 2,8/50mm and the Rodagon APO N 2,8/50mm and found no differences ....

In color I am only printing till 24x30cm (ACP-252) and in this format I also could not find any differences.


These tests I made with the aperture 2 F stops closed for both enlarging lenses.

Not sure you will find any differences at 40x50cm or bigger in RA-4 color printing.
 
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