Difference between Sironar-N & Sironar-S

[Gene McCluney]

I know I can look up the specs, but I was just wondering what is the overall difference between a Rodenstock Sironar-N and Sironar-S lens. Did one replace the other? Is one better for coverage?

[Richard K.]

The S has 75 Deg coverage vs 72 Deg for the N, may have different glass type (ED) in construction and should be slightly (although you may need a loupe to see this) sharper in the corners. The S's are said to be the sharpest current lenses but I'm sure we can argue that point...:)

[Oren Grad]

N and S were offered together for about a decade - I'm sure Bob S will recall the exact details. Most of the N series was discontinued recently; only the 150 and 210 remain current. The S series continues.

The Rodenstock literature makes these points about what the S offers compared to the N:


Coverage increased from 72 to 75 degrees, allows greater shifts

Elimination of secondary spectrum due to use of ED glass, eliminates visible color fringing even at edges with extreme contrast

Reduced fall-off

Can use f/16 as working aperture [presumably as opposed to f/22]

Special strength of S is when complex, fine structures in the outer part of the image circle need to be reproduced


There's been plenty of discussion here over the years about the extent to which users perceive these advantages in practice.