Hi, everyone.

I recently acquired a Rodenstock 480mm APO Ronar f/9 barrel lens. I noticed that if you turn the aperture past nine, it keeps on getting larger (noticably) before the petals are out of the line of view through the lens, maybe f/8?

So, I guess my question is, what does this mean on a lens? If you go into this aperture area, are you actually getting more speed, or am I just a very wishful, somewhat slow, thinker...

Thanks, Pete.

-- Peter Chipman (chippete@yahoo.com), April 08, 2002

Answers

Pete,

While I doubt that your Ronar opens much more than f/9 (mine certainly doesn't), the point is really quite moot because focused beyond 1:8 or so process lenses aren't very sharp at wide apertures. This is similar to Schneider's not delimiting f/64 on many of their modern lenses (e.g. the 150mm Symmar-S)--although these lenses can physically stop down to f/64, the effect of defraction is such that they are too soft.

That said, if it is worth the time, please do a test on film, checking to see if indeed it opens wider than f/9, and if the resolution is good--I would love to see the results!

-- jason (sanford@temple.edu), April 08, 2002.

Will do. Thanks for the response. I figure the camera will be built in another 3 weeks, so I'll be able to post some results at that time.

The petals are really a thing of beauty on the lens. I spent 5 minutes just watching it open and close when I got it..., oh boy...can we say "addiction?"

Pete.

-- Pete Chipman (chippete@yahoo.com), April 08, 2002.

The barrel mount is used for different lenses. It is not specfic to the lens you have. As the aperture is a ratio of the actual focal length and the opening size the mounts have to be adjusted to the specific optic mounted in it. So the aperture scale usually goes beyond the marked area of a specific lens.

the lens you have came from a process camera and you probably have a filter slot in the mount. Make sure this is closed tight or you will ruin your exposures. You might also investigate having the lens mounted in a shutter.

BTW, the 485mm is an Apo Ronar CL not an Apo Ronar. The 485 was only a CL which means it has a linearized aperture scale. The Apo Ronar series does not..

-- Bob Salomon (bob@hpmarketingcorp.com), April 08, 2002.

Sorry,

I thought you had the 485. The 480mm was available in both CL and non CL versions. The photo version was not CL.

The graphic arts version was available in CL and non CL.

-- Bob Salomon (bob@hpmarketingcorp.com), April 08, 2002.

Also the 480 in Copal 3 is a 9.0 but in Compu or Prontor Prof. 3 it is an f11.

-- Bob Salomon (bob@hpmarketingcorp.com), April 08, 2002.

Question for Bob S.

Does the 480 APO Ronar in barrel mount directly into a Copal #3 or does it need to be custom fitted, a la Steve Grimes? Same question for ZEISS APO-TESSAR 450mm or APO-NIKKOR 480, both F9.

TIA

-- Paul van der Hoof (paul.vanderhoof@losangeles.af.mil), April 08, 2002.

You would have to check with any camera repairman with the lens in hand. The aperture scale also has to be engraved and the age of the lens may make a difference in the threads.

-- Bob Salomon (bob@hpmarketingcorp.com), April 08, 2002.