View Full Version : APO-Ronar vs. APO-Ronar-CL ??

Harley Goldman
20-Oct-2003, 11:38
What is the difference between the APO-Ronar and the APO-Ronar-CL lens? Is the latter suitable for landscape photography? I assume the APO-Ronar is, as it is current sold by various camera stores.

I am looking for a lightweight 360mm lens and the G-Claron is a little bigger than I would like, so I have been researching the Rodenstock line. I understand the Fujinon-A is a candidate, but is extremely hard to find (per the info at Kerry Thalmann's website).

CP Goerz
20-Oct-2003, 12:00
The CL Ronar uses a special compound to hold the elements in alignment through extremes of temperature. When manufacturers changed from brass to aluminum to make lens mounts/barrels they found/already knew that aluminum expanded/contracted more than brass did and most just allowed a little more slop to cover. Rodenstock made this compound to ensure that the elements stayed in the factory set positions. A chap in the process lens recalibration/repair field told me that little snippet and he often bemoans aluminum barreled lenses as being inferior to brass ones.He's one of the top dogs in that biz so tend to take his information without any salt.

CP Goerz

Bob Salomon
20-Oct-2003, 12:01
Linearized aperture scale vs non linearized aperture scale. Both are corrected for 1:1 of 2 dimensional art. Neither is corrected for landscapes.

CP Goerz
20-Oct-2003, 12:02
PS:I sold a 360 Fuji on Ebay a few months ago, nice lens. Have you thought of a Red Dot Artar instead? They are small, coated, often in shutters, and very sharp.

CP Goerz

Arne Croell
20-Oct-2003, 15:49
CP Goerz is correct about the CL. My (German) Rodenstock brochure on their process lenses (late 1980's) states that instead of the usual mechanical mounting the CL lenses are first centered/oriented in the mount using autocollimation (an optical method for centering) and are then permanently fixed in that position by injection of some plastic. According to Rodenstock this reduces stress-induced birefringence of the glass and reduces the variation of the MTF in production from 0.1 down to 0.05.
Although the Apo-Ronars are not optimized for infinity, they (as well as the similar Apo-Artars, Apo-Germinars, and Apo-Nikkors) hold their corrections well at infinity. MTF graphs for a 240mm Apo-Ronar at infinity (as well as 1:1) can be found here: http://www.butzi.net/rodenstock/apo-ronar/p12.htm

Harley Goldman
20-Oct-2003, 16:11
Are these lenses multi-coated? Single coated? Based on what has been said, I would assume that for landscape work, there would be no functional difference between the CL and non-CL versions?

Arne Croell
20-Oct-2003, 16:17
Late Apo-Ronars sold in shutter are multicoated (either marked MC on the front lens cell or with a blue ring around it), the barrel process lens versions are usually single coated. However, I have used a 300mm multicoated Apo-Ronars and a single coated 300mm Apo-Germinar and have not seen any significant difference.

Bob Salomon
22-Oct-2003, 07:25
"My (German) Rodenstock brochure on their process lenses (late 1980's)"

Unfortuantely I have the latest Process Lens brochure from Rodenstock (3/94) in which they state only:

" The Apo-Ronar CL is primarily used in horizontal and vertical cameras. The closely spaced focal lengths range from 150 to 1800mm. ALL APO-RONAR CL LENSES HAVE LINEAR APERATURE SCALES - EXCEPT FOR THE 150MM LENS. (WHICH DOES NOT CARRY THE CL SUFFIX AND HAS NO LINEAR APERTURE SCALE). The angle of field is 48° for lenses up to and including 480mm, above that it is 40 - 46°. Most Apo-Ronar CL lenses are 4 element systems. For specially demanding jobs, for instance map making, Rodenstock has also developed six element versions of 600, 800 and 1200mm. A slot in the lens mount takes filter holders.

In the older (6/82) Process Lens brochure Rodenstock does describe the special centering process and the delicacy required to center Apo Ronar lenses. It then goes on to state:

"As already mentioned, the Apo-Ronar system is somewhat delicate when it comes to centering, which is why IT BENEFITS FROM THE SPECIAL CASTING-IN PROCESS RODENSTOCK DEVELOPED FOR THIS PURPOSE.

That refers to all Apo-Ronar designs - the Apo Ronar, the Apo Ronar CL, the Apo Ronar M, the F Theta Ronar, etc.

The difference between the Apo Ronar in NF mount and the Apo Ronar CL in NF mount is the linearized aperture scale on the CL. The CL was not multi coated.

All Apo Ronar lenses are no longer made.

Arne Croell
22-Oct-2003, 13:52
Bob, the CL's certainly do have the linear scale which sets them apart from the normal ones as you stated. As for the centering I have the German brochure (also printed 1982, I just got it in the late eighties) in front of me. It says under the heading "A New Type of Mounting" ("Eine neue Art der Montage"): "In the Apo-Ronar series named "CL" the lenses are centered in the mount by autocollimation and are then fixed in the mount with a suitable plastic" ("In der mit "CL" bezeichneten Serie der APO-RONARE werden die Linsen mit Hilfe des Autokollimationsverfahrens in der Fassung ausgerichtet und dann mit einem geeigneten Kunststoff formschlüssig in die Fassung eingegossen"). In another section on that page under the heading "Apo-Ronar/Apo-Ronar CL" Rodenstock writes first about the Apo-Ronars in general, then about the normal nonlinear aperture scale, and then about the advantages of the linear scale, saying about the latter: "There the angle from one aperture to the next is constant. Therefore a second series of Apo-Ronars is delivered with linearized aperture. These are also the lenses mounted with the new method. ("Da ist der Drehwinkel von einer Blendenstufe zur anderen konstant. Eine zweite Reihe von Apo-Ronaren wird deshalb mit linearisierter Blende geliefert. Das sind zugleich die Objektive, die nach dem neuen Verfahren montiert sind"). From this text I conclude that only the CL version uses that centering method - at least at the time of printing of this brochure. Later things may have changed of course. [Translations are mine; original German quotes in parentheses]

Bob Salomon
22-Oct-2003, 14:22
"NF mount is the linearized aperture scale on the CL" Arne,

That is what I did say. The CL had a linearized mount the Apo Ronar in NF mount did not.

In shutter the Apo Ronar could have the linearized scale. This only applies to them in NF mount.

Yes the CL had the special centering. But that changed over time and all Apo Ronars were made that way. You are looking at a 21 year old brochure. Mine is a decade newer.