View Full Version : Calculating Lens Coverage

03-08-2011, 06:59 PM
Does anyone know whether angle of coverage refers to the complete angle or just from the lens centerline to the edge of the coverage area? Hope that makes sense.

Rodenstock has a 48* angle of view listed for their 890mm Ronar which would either translate to about a 15" circle or a 38" circle. Quite a big difference.

Any help appreciated.

Dan Fromm
03-08-2011, 07:09 PM
Full angle. A 48 degree 890 mm lens covers a 792 mm circle.

But and however, Rodenstock's Repro Handbuch says that the 890 covers 40 degrees at f/32. In which case, 648 mm.

03-08-2011, 07:12 PM
a = 2*arctan(d/2f)

The angle of view (a) is given by the above equation, where ‘d’ is the dimension of the negative-format diagonal and ‘f’ is the focal length. 'a' is the complete angle of coverage.

03-08-2011, 08:00 PM
Thanks both, any idea what the lens is worth? I'm finding absolutely nothing with google.

Dan Fromm
03-09-2011, 06:11 AM
Impossible to predict selling price, its a thin market. That said, and even though I bought a perfectly fine 900/10 Apo-Saphir for 101 Euro last fall, 900 mm process lenses typically bring more than $500, sometimes considerably more. But sometimes less. Look for completed auctions for Apo Ronars and Apo Nikkors on eBay. These days Google returns mainly irrelevant garbage.

Just put the thing up for sale on eBay and accept what you get.