Archived posting to the Leica Users Group, 1999/11/10
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]- --============_-1269851337==_ma============ Content-Type: text/plain; charset="us-ascii" ; format="flowed" Vario-Elmarit-R 2.8/35-70 Some background info. The first 35mm zoomlens was the Voigtlander Zoomar 2.8/36-82, a cooperation between the inventors (Zoomar Cy) and the producers (Voigtlander). The early zooms had a remarkable property that is almost lost today: the constant aperture over the full range. Also the exit pupil was a constant, as the older cameras had no AF and AE to compensate for focus changes and illumination differences. But these demands stressed the design optically and so the earlier zooms were optically not that good. When it became possible to use more plastics to compensate for the corrector shift and to use more separate lenses and to bring the aperture position into one of the moving lensgroups, the optical performance could be enhanced, but the price was a reduction in aperture when zooming to the tele-position. A zoomlens with a constant aperture and excellent image quality demands many single lens elements and a large physical volume for correction purposes. The Leica V-Elmarit 2.8 is twice as heavy as theLeica V-Elmar 4 and its volume is 800 versus 300 in volume units, so again more than twice the volume. The macro position gives a 1:2.8 reduction which is quite useful, but the shallow depth of field necessitates a small aperture, even if the full aperture performance is very good. The sharpness/unsharpness gradient is intriguing. Leica lenses are supposed to have mythical qualities in this respect. This V-E has a quite steep gradient from sharp to unsharp. The first zone of unsharpness exhibits shape preservation, that is the larger objects keep their geometrically correct form, but loose detail information and in the second zone shapes loose their characteristic form and become amorphous color blotches of various patterns. The very large object forms have somewhat harsh outlines. On the borderline of sharp/unsharp the outlines of details are a bit rough and have the character of a Van Gogh brush. Atmospheric perspective is enhanced and the sharpness plane is pressed into view quite forcefully. The etchingly sharp outlines of the grosser details are preserved over a large zone in the sharpness/unsharpness border. This effect is most visible in the 70 position. The 35 position naturally has these effects to a smaller degree and with a smoother gradient. Modern Leica lenses have these characteristics as a family trait: quick change from sharp to unsharpness with shape preservation and a progressive loss of fine detail information. Night pictures are quite demanding as specular highlights, deep shadows and large bright light sources generate secondary reflections and veiling glare and halo effects . The V-E is outstanding here. No coma at all: in the critical zone in the negative (2/3 from the axis that is the zone of 12 to 18mm from center), light sources are cleanly delineated, hold their shape and are without any halo rings. Light sources very close together at far distances are separated clearly and without fuzzy rings and have a brillantly clear luminance. Dark shadows are clean black and the darker colors have fine color hues. Often you see here a bit sooty blacks and colors and light sources look as it photographed in a misty atmosphere. Erwin - --============_-1269851337==_ma============ Content-Type: text/enriched; charset="us-ascii" <fontfamily><param>Arial</param><smaller>Vario-Elmarit-R 2.8/35-70 Some background info. The first 35mm zoomlens was the Voigtlander Zoomar 2.8/36-82, a cooperation between the inventors (Zoomar Cy) and the producers (Voigtlander). The early zooms had a remarkable property that is almost lost today: the constant aperture over the full range. Also the exit pupil was a constant, as the older cameras had no AF and AE to compensate for focus changes and illumination differences. But these demands stressed the design optically and so the earlier zooms were optically not that good. When it became possible to use more plastics to compensate for the corrector shift and to use more separate lenses and to bring the aperture position into one of the moving lensgroups, the optical performance could be enhanced, but the price was a reduction in aperture when zooming to the tele-position. A zoomlens with a constant aperture and excellent image quality demands many single lens elements and a large physical volume for correction purposes. The Leica V-Elmarit 2.8 is twice as heavy as theLeica V-Elmar 4 and its volume is 800 versus 300 in volume units, so again more than twice the volume. The macro position gives a 1:2.8 reduction which is quite useful, but the shallow depth of field necessitates a small aperture, even if the full aperture performance is very good. The sharpness/unsharpness gradient is intriguing. Leica lenses are supposed to have mythical qualities in this respect. This V-E has a quite steep gradient from sharp to unsharp. The first zone of unsharpness exhibits shape preservation, that is the larger objects keep their geometrically correct form, but loose detail information and in the second zone shapes loose their characteristic form and become amorphous color blotches of various patterns. The very large object forms have somewhat harsh outlines. On the borderline of sharp/unsharp the outlines of details are a bit rough and have the character of a Van Gogh brush. Atmospheric perspective is enhanced and the sharpness plane is pressed into view quite forcefully. The etchingly sharp outlines of the grosser details are preserved over a large zone in the sharpness/unsharpness border. This effect is most visible in the 70 position. The 35 position naturally has these effects to a smaller degree and with a smoother gradient. Modern Leica lenses have these characteristics as a family trait: quick change from sharp to unsharpness with shape preservation and a progressive loss of fine detail information. Night pictures are quite demanding as specular highlights, deep shadows and large bright light sources generate secondary reflections and veiling glare and halo effects . The V-E is outstanding here. No coma at all: in the critical zone in the negative (2/3 from the axis that is the zone of 12 to 18mm from center), light sources are cleanly delineated, hold their shape and are without any halo rings. Light sources very close together at far distances are separated clearly and without fuzzy rings and have a brillantly clear luminance. Dark shadows are clean black and the darker colors have fine color hues. Often you see here a bit sooty blacks and colors and light sources look as it photographed in a misty atmosphere. Erwin </smaller></fontfamily> - --============_-1269851337==_ma============--