Super-Angulon 21mm f4 was announced at Photokina in 1958. This Photokina heralded a big year for Leica. Besides Super-Angulon, other new lenses included Summicron 35mm 8-elements, Summaron 35mm f2.8, Summilux 50mm 1st, Elmar 65mm f3.5 for Visoflex, summicron 90mm with lens shade, and Elmar 90mm f2.8. Also introduced at the same time were the Visoflex II and Leica M1.
Designed and produced by Schneider, production of the Super-Angulon began in 1958 but didn’t really get going until 1959. The lens was a semi-symmetrical design with 4 groups and 9 elements. The rear elements reach back into the camera almost to the shutter curtain. This design was excellent for distortion suppression, but today’s use of digital cameras results in changes in the color at the corner. The lens was slightly faster then the earlier Biogon 21mm f4.5 for Contax. The Leitz lens had an E-39 filter thread so that it would take standard Summicron 50mm filters and lens cap, and there was an accessory lens hood IWKOO and separate, special deep rear caps for either SM or BM mount. Clickstops were at all full apertures. Focus was rangefinder coupled down to 28 inches and then manual focus down to 16 inches for close-up work. Super-Angulon was produced in screw-mount. Bayonet mount lenses had an adapter ring attached secured by a small setscrew. Thus, all lenses could be used on either type of camera. but those that were delivered as SM lenses did not have the adapter or the small hale made for the point of the setscrew, and since those lenses are far fewer, they are considered more valuable today.
The lens had some curvature of field of the “positive” variety, with closer focus around the edges of the frame, which was useful for extending the depth still closer to the camera, especially at large apertures. The depth of filed in a vertical photograph made while standing with the lens focussed at 10 feet, could encompass everything from infinity to the grass under foot at f/4. there was some falloff in corner illumination at f/4, but the good sharpness and depth made this aperture quite usable nontheless.
Edge sharpness varied somewhat between individual examples of the lens, improving with stopping down. The field curvature prevented really crisp imagery in the corners at infinity, but became generally good at closer distances. Central sharpness was, however, excellent in all of the examples I have tested. The Super-Angulon 21mm f4 had only a very few, well-controlled reflections when the sun was in the frame. But, if this practice was prolonged over time, the paint around some of the interior elements could begin to flake off from the internal heat, and the lens would begin to suffer loss of contrast at the largest apertures due to reflections from these bright edge surfaces. To fix the problem, the element edges would need to be repainted by the Leitz Service Dept.
The shallow round lens hood IWKOO was available separately, but since the lens was essentially backlightproof, the use of the hood was not all that necessary. Of more concern to me was the chrome surface of the lens flange surrounding the front element. I was always afraid that this bright surface would cause reflections if the light from the sun should be reflected off the inside surface of a filter and into the lens causing loss of contrast. But I never really saw this effect, and I never bought the hood either. The hood did cut off some of the view at the bottom center of the frame in the brightline viewfinder, though; so most photographers I talked to never bought the hood either. The hood is something of a rarity today, as is the deep metal SM rear lens cap OIXMO.
The Super-Angulon’s tremendous depth of field was particularly useful for deep depth photographs and close-ups. Quite sharp at the smallest apertures, depth could be maintained from infinity down to approximately one foot at f/16, and even closer at f/22, but with some loss of resolution due to diffraction. The depth of field scale stops at f/16, presumably because the marks for f/22 would nearly meet at the back of the lens mount!
One particular talent of the Super-Angulon 21mm f4 is in photographing architects’ models, or such things as model train layouts. With the focus set at 16 inches, and aperture at f22, depth of field can extend from about four feet to about three inches, and with good corner sharpness. The field curvature helps with the corners, but one other factor is of even greater importance – the size fo the lens flange! The small lens barrel allows the center of the lens (without shade) to be positioned less than the picture of the model appears to have been taken from approximately a scaled down person’s standing height. You can actually look up at a model locomotive or building, for instance, and not down from an artificial “helicopter” height made necessary by the large front flange of a reflex lens. The Super-Angulon 21mm f4 still finds occasional use in my lens lineup for this sort of thing. It can also focus closer than 16 inches by screwing the lens out slightly and/or shimming it, but this requires testing on film to find the exact focus distance. When shooting these close-ups, in order to overcome parallax problems, I sight through the brightline finder and get the exact framing I want and then raise the tripod center post the precise distance between the centers of the viewfinder window and the lens 2.25 inches with the plastic bodies finder. This procedure removes any parallax error, but bear in mind that on an extremely close picture, the viewfinder will show slightly more than is captured on film due to the extension of the lens.
to be continue..