Archived posting to the Leica Users Group, 1998/01/27
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Super Angular 4,0/21mm: At full aperture light fall off is quite noticable, so is curvature of field. Distortion is hardly visible. At full aperture the image field from center to a radius of 5mm gives good sharpness and medium contrast. The object outlines are well defined, fine and very fine details are a little bit soft. Extremely fine details are very soft with low contrast. So in fact hardly visible. From 5 mm the image contrast drops rapidly and from 8mm vey fine detail ist just noticable and fine detail is visible with low contrast. From 11mm astigmatism begins to reduce the visibility of fine detail. Subject outlines are rendered softly and in the corners even these details are unsharp. Stopping down naturally improves the quality. Contrast however stays at a low to meduim level. Stopping down to f/8 enhances contrast a little, extremely fine details are visible, but not in the corners and the outer zones (in horizontal view: the long side of the negative). At f/11 the optimum is reached and from f/16 the performance drops. There is slight decentring. Generally speaking: this lens at full aperture gives a good performance in the center and if the clear rendition of very fne detail is not the prime objective this aperture is usable. Modern performance is not possible even at optimum aperture. Super Angulon 3.4/21mm: At full aperture distortion is negligable, light fall off is reduced and curvature of field well corrected. At full aperture the center image within a radius of 8mm gives a crisp rendition of subject outlines and fine details.,the corners being very soft. Very fine details are rendered with medium contrast from center to 6mm and with lowish contrast from 6mm to the corners. Extremely fine detail is just visible, with veruy low contrast and soft edges from center to about 10mm radius, vanishing in the outer zones. At f/4 this lens is a marked improvement on the SA 4.0. AT f/5,6 contrast is improved and extremely fine details are now clearly visible till the outer zones, the crners still being soft. At f/8 the optimum is reached, the rendition of extremely fine details is good with a medium contrast. AT f/11 and smaller the performance drops. generally speaking: this lens is a very good performer. its fine qualities only restricted by the presence of astigmatism that reduces contrast and crisp rendition of very fine detail. There is slighrt decentring. Elmarit-M 2,8/21mm: At f/2,8 the light fall off is slightly below SA 34 levels. Flatness of field is less well corrected as is distortion. At full aperture the center image with a radius of 10mm gives a slightly crisper image than the SA34. The generally somewat higher contrast results in a more clear delineation of fine details. Outer zones and corners are soft. The general performance of the E is s little above that of the SA 34 wide open. This is partly due to the reduction of astigamtism, resulting in improved rendition of fine details. At f/4 extremely fine details are visible with good contrast from center to a radius of 6mm. From there to the corners the image details become progressively softer, but fine details stay within detectable range, The optimum is reached at f/8 with a good reproduction of extremely fine details till the outer zones. The subject outlines, especially in the outer zones have slightly soft edges, giving an overall impression of a smooth but not brittle sharp image. Stopping down to f/11 and smaller reduces the quality. Decentring was not measurable. generally speaking: this lens is a commendable performer and a slight improvement on the SA 34. It does not bear the Leica badge with full honour. Elmarit-M 2,8/21 ASPH: At full aperture contrast is high and extremely fine detail is very crisply rendered from center over a raduis of 11 mm. From then the contrast of edges drops a little but is still vastly superior to all its predecessors. Astigmatism and curvature of field are almost fully corrected. Subject outlines and fine details are extremely sharp and clearly almost lucidly rendered. In the outer zones and the corners this superior performance drops naturally. The overall image quality is a quantum leap forwards in relation to all predecessors and I may add competitors. To set it in perspective: the performance at f/2.8 is better in all respects to the SA 34 at f/5.6. Or: the max resolution of the SA 4 at f/,0 is about 70lp/mm with very low contrast where the ASPH at f/2.8 has 125lp/mm at high contrast. AT f/4,0 contrast and the clear rendition of very fine details improves, with the corners still lagging behind. At f/5.6 the optimum is reached with exceptional performance including the far outer zones. From f/8.0 the performance drops ever so slighly and at f/16 is visibly below optimum. Decentring is not measurable. Overall: this lens gives outstanding image quality at full aperture and improves till f/8.0. It is by a great distance the best 21mm in the Leica stable and the only choice for the person who needs superior performance from a 21 starting at 2.8. A full report giving more details about flare, close-up performance and the hot topic of performance at infinity will be published at my site in a week. Erwin