I was looking at the cross sections of this lens in my Leicaflex SL and SL2 manuals and there seems to be a difference in the rear group. Was there a redesign? Can anyone verify this via a better source(lens book)? Do all 21mm SA-R lenses have the very basic four blade diaphragm?

-- Steve Rasmussen (srasmuss@flash.net), November 10, 2001

Answers

Erwin Puts says in his Leica Lens Compendium that both 3.4/21 Super Angulons used "the same optical scale." I have the R version and it has a 4-blade diaphram. I don't know whether all do or not.

(By the way, I use the R model not only on my Leicaflex I (for which it was built) but also with an R-to-M adapter with my M Leicas.

-- Jack Matlock (jfmatlo@attglobal.net), November 10, 2001.

Sorry, I should have written "the same optical cell" in the previous post.

-- Jack Matlock (jfmatlo@attglobal.net), November 10, 2001.

I should add that it is the f/4 21mm SA-R.

-- Steve Rasmussen (srasmuss@flash.net), November 10, 2001.

It has the same design for all its production run (1968 to 1993).

Cheers,

-- John Collier (jbcollier@powersurfr.com), November 10, 2001.

Per Lager's book, as John Collier said, there was only one design.

Two possibilities come to mind for the variation you see in the manuals: 1) A redesign was planned at the time of the SL2 introduction, and that design was used for the drawing but never implemented. 2) There may have been a change in the diameter of one of the rear elements (for, say, production reasons) that did not affect the curvature of the element, so the optical light path stayed the same.

RE: 1). Something like this happened when the 21 f/2.8 for the M was introduced. The prototype had a straight barrel and a 49mm filter size, and was so illustrated in some brochures. But by the time it was actually manufactured the front was redesigned to the E60 bell shape.

-- Andy Piper (apidens@denver.infi.net), November 10, 2001.

I own 2 21/4 S/A-R lenses, one from 1970 and the other from 1983. They are identical at least from what a close physical inspection reveals. I have seen at least a couple samples where the diaphragm actuating mechanism was slightly different, but otherwise no changes. All of them have the 4-blade diaphragm.

-- Jay (infinitydt@aol.com), November 11, 2001.