Rodenstock 180mm f/5.6 Sironar

[bob fowler]

I recently bought yet another Toyo monorail (a D45M this time) via

that famous on line auction site. Included with the deal was a

Rodenstock 180mm f/5.6 Sironar in a #1 Synchro Compur. I cleaned the

slow speeds escapement which got the shutter working correctly and

shot some test images. The end result, I like the lens.

 

There is a ton of information about the Sironar-S and Sironar-N

available, but I can't seem to find anything about the plain old

Sironar. Can anyone clue me in as to the design of the lens

(elements/groups) and other specs such as coverage angle and image

circle?

 

TIA

[michael_briggs2]

<p>"Sironar" is Rodenstock's name for plasmat-type lenses. The descendents of the original Sironar are today's Apo-Sironar-N and Apo-Sironar-S. As plasmats, they have 6 elements in 4 groups and circa 70 degrees coverage. Rodenstock has squeezed a few additional degrees out of their current designs, but this isn't super important for a plasmat with a focal length longer than the format diagonal, such as your 180 used with 4x5.</p>

 

<p>Kerry Thalmann wrote an article about the history of Rodenstock lenses for the Sept/Oct 2002 issue of View Camera magazine. You might still be able to get a back issue, or the article on a CD (<a href="http://www.viewcamera.com/">http://www.viewcamera.com</a>). He states that the Sironars were made from the mid-1960s to the mid/late 1970s. As such, they will be single-coated. You can date your lens from the table that Kerry has on his website: <a href="http://www.thalmann.com/largeformat/agevs.htm">http://www.thalmann.com/largeformat/agevs.htm</a>.</p>

 

<p>From an original 1966 brochure that I have, Rodenstock spec'd them as covering 70 degrees or slightly more. They listed the circle of coverage for infinity and f22 of the 180 mm Sironar as 252 mm diameter, which is 70 degrees.</p>

 

<p>They also suggested using the front component alone (i.e., unscrew the rear cell) to obtain an approx tripling of the focal length, either as a long focal length lens, or wide-open, as a soft-focus portrait lens. This will change the aperture of the lens by a factor of 3 off from the values marked on the scale. You will have to experiment to see if you find the result of acceptable quality.</p>

 

<p>The convertible mode may have been needed to compete with the contemporaneous Schneider Symmar. The cross-section of the Sironar looks less symmetrical than that of the Symmar, so the Sironar may be a more advanced design and closer to today's plasmats than the Symmar.</p>

[bob fowler]

Thanks Michael. I did some shooting with it this past Saturday and am quite happy with the lens. Considering that I was happy to get just the camera, extension rail, and hard case for what I paid for the whole outfit (about $300), it was quite a pleasant surprise. I didn't have a 180mm in my arsenal (well, not one that would cover 4X5) so it's a keeper.