I am hoping to buy a used 210mm Rodenstock Sironar N, which I understand is the same as an Apo-Sironar N. But I see a Rodenstock Sironar for sale on eBay, with no letter following. Where does that lens sit in the lineup? Is it as good as the much-praised N/S/W versions?
According to this list, the 210mm Rodenstock Sironar N, the 210mm Rodenstock Sironar, and the 210mm Rodenstock APO Sironar differ in the sizes of the image circles they project:
- The 210mm Rodenstock Sironar casts an image circle of 266mm (10.47 inches)
- The 210mm Rodenstock Sironar N casts an image circle of 286mm (11.26 inches)
- The 210mm Rodenstock APO Sironar casts an image circle of 352mm (13.86 inches)
This is significant if you plan to use movements with your view camera and also desire to use the full 5x7 inch format size.
There's also a difference in the number of elements/groups in the optical formulae between the Sironar N (6/4) and the APO Sironar (7/5). The number used by the Sironar is not indicated.