Archived posting to the Leica Users Group, 1998/05/27
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Alf wrote: >>I vaguely recall another person who said the same about the 21 ASPH. >>Hmmmm...I am beginning to wonder if it might be wiser to hold on to my >>21/3.4 Super-Angulon until the dust settles. > > >I swear, you'd bite the table if you gave that lens away ... ! Only if you were on your hands and knees and stumbling about in that position :-). Actually, since October I've had both types of Elmarits and the SA/3.4, and find that except for the f/22 and closer focussing of the SA, and the much smaller extension, the 21asph. is essentially as good. The asph has more distortion (slight) than the SA, and the SA has more light falloff into the corners. As far as other optical characteristics, it's a tossup, with the better coatings, the 1/2 stop speed and the ability to meter giving the 21 asph the edge in practical usage. The older 21 is generally similar to the 21asph, with _slightly_ lower optical performance. Any of them are better than virtually any SLR lens of similar focal length. BTW, at some time 'retrofocus' was defined as a lens whose rear nodal point was between the lens and the film, but generally a retrofocus lens has its rear nodal point further towards the lens than you would expect with 'normal' construction, resulting in a greater than 'normal' distance between the rear element and the film. Leica M lenses started using retrofocus designs after the M5 was introduced, with the first lens being the 28/2.8. The 21/2.8 Elmarit came out to replace the 21SA for the same reason, but in general was a step down in performance when used very critically. Someone mentioned that you can meter with the Leica Hologon 15 on the M6. I'm sorry, it doesn't work. The rear element is too close. I have an M4 that I use with this lens and the 21/3.4, as metering is not possible. While resolution and contrast in retrofocus wideangles have improved over the years to our present standards, the best non-retrofocus wideangles still tend to be significantly better, as witness the Super-Symmar XL lenses. One area in which retrofocus lenses still have some problems is in the area of distortion, where the characteristic compound distortion is still present in every retrofocus lens I have seen. On the other hand, retrofocus lenses usually have much better eveness of illumination out of the box than non-retrofocus lens, due to the cos to the 4th effects not being as great precisely because of the retrofocus design. * Henning J. Wulff /|\ Wulff Photography & Design /###\ henningw@archiphoto.com |[ ]| http://www.archiphoto.com