apo ronar 300 as an enlarger lens

[quigon]

hi everybody
is it possible to use a Rodenstock apo ronar 300mm as an enlarging lens, and is it a reasonable idea?
thanks

[Geert]

Sure it is. The ronars-in-a-barrel are process lenses, so I don't think you will exceed the optimized magnification ratio when using it as an enlarging lens.
There are better solutions but if it's the only lens available, in that focal length, to you, do use it.

G

[Ernest Purdum]

The criteria for enlarging and process lenses are quite similar, so the two families of lenses are much alike except for aperture. The larger aperture of enlarging lenses is a convenience, but the results from the use of process lenses for this purpose can be excellent.

[Michael Gudzinowicz]

The lens is fine, but the feasibility depends upon the rest of the plan. The carrier to easel distance you'll require is 300mmX(2+M+1/M), where M is the print magnification. For instance, a 3X print requires 1600mm from the carrier to easel, or 62" (5 feet+).

[Geary Lyons]

The difference between a process lens and a purpose designed enlarging lens is the magnification ratio for which the optics are optimized. Generally, process lenses are optimized for 1:1 reproduction. Depending on the focal length, (relative to film format), enlarging lenses are generally optimized for magnification ratios 1:2 or greater. The smaller the focal length, the greater the ratio required. Logically, it makes sense that an 80mm for 6x6 would be optimized closer to a ratio around 1:5, whereas a 300mm would be optimized for a ratio around 1:3 and a 360mm at 1:2. So the 300mm focal length has little deviation from the optimized design at reasonable print sizes.

All of that aside, I use a 300mm Apo-Ronar for 8x10 work. It works great! It is sharp and contrasty. But if you are used to working with purpose built enlarging lenses, the lack of click stops and the orientation of the f-stop lettering is a user interface challenge. The smaller working aperatures make print times longer, as well. I have an "Angel" in the group here that is sending me a 300 purpose built enlarging lense. I'll report back my experiences.

Cheers,
Geary