Didn't see this in the archives or in Google search. Does anyone know the cover age of a Goerz Dagor f7.7 180mm lens? Just purchased one and will primarily use on a 4x5, but is there any chance of it covering 8x10 stopped down? Thanks.
Didn't see this in the archives or in Google search. Does anyone know the cover age of a Goerz Dagor f7.7 180mm lens? Just purchased one and will primarily use on a 4x5, but is there any chance of it covering 8x10 stopped down? Thanks.
I just sold a f6.8, 7 inch, Goerz American Optical Company Dagor that I had for a number of years. While I don't have documented image circles, this lens had coverage similar to a standard 180mm plasmat lens. (e.g. Symmar-S.) Assuming that image circle for a design of lens is proportional to focal length, the published image circle of a 150mm f6.8 Gold Dot Dagor is 210 at f22, implying that the image circle of a 7 inch f6.8 Dagor at f22 is 250mm.
Based on my experience, the 180mm lens will not cover 8x10, even stopped down. The published image circle for a wide angle 165mm Dagor is 289mm, and that even this lens will cover 8x10 only when stopped down to f32. I have heard that the f7.7's have a somewhat larger image circle than the f6.8's. Still, it doesn't seem like this would be enough extra image circle to cover 8x10.
I have a copy of an old Goerz Dagor coverage chart with data for 7" f6.8, 87degrees at f45 covering 8x10. only 5x7 wide open. Good luck, Tracy Storer, Polaroid 20x24 San Francis
Posting Permissions
Reply With Quote
Bookmarks