Archived posting to the Leica Users Group, 1999/05/19
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Somebody wrote: "Me, I don't care; there's such abundance of information coming from him that no matter how careful he needs be with Leica management, the results of his studies remain most valuable. Or does anyone know of a worthy alternative to his tests?" YES I DO. Shoot a roll of film, the brand you use most. Make sure you have the camera on a tripod. One shot at each f-stop. As there are more frames on a film than there a f-stops, you may wish to make two or three series at different distances. Develop as you always do and make some enlargements the largest size you normally make. There is normally no need to make enlargements corresponding to all f-stops. Then compare with same size enlargement (___ same subject___) from a negative ( same film, same developer etc..) made with a lens you know is good/excellent or whatever standard you set. You may look at the centre or the corners or wherever you want, or you may look for microcontrast or if squares look like cushions, or whatever, but look only for those things that are important to you. If you can not see any difference from one lens to another using this test method, then the difference is not important enough _for you_ (... and for this type of test I would not use that mini-skirted model that we read about in an test announcement recently) >Thank you, Erwin, particularly for the "real world" commentary following >the testing results. > AGREED > >Erwin Puts wrote: > >> A comparison of the 28mm Ricoh GR and the Elmarit-M and R versions of >>the 28mm. >> >> The Ricoh (#02818) is a diminuative lens. The chrome version with the >>focusing aid is very Leica like. Mechanically it showed a slight axial >>play in the distance ring mechanism and a very slight decentring. >> At full aperture (2.8) the lens shows a medium to high contrast, with >>some light fall off in the corners. In the center very fine detail is >>recorded with medium microcontrast and slightly soft edges. Extremely >>fine detail is just recorded with very soft outlines. This type of >>performance holds on axis over a circle with a 4 mm radius (an area of 8 >>to 10mm diameter). In the field (the outer zones) fine detail is recorded >>with high contrast. The edges however show colour finges and there is >>also a trace of astigmatism. Fine and very fine detail is fuzzy, but just >>visible. The corners are very soft with outlines of large subject detail >>clearly visible. >> At f/4,0 the image crispens and the overall contrast becomes high. On >>axis the edges of fine detail clearly sharpen,. In the field the >>improvement is slight. At 5.6 the overall image is still a bit soft in >>the field. At f/8.0 we get an excellent image with extremely fine detail >>clearly resolved, with a faint trace of softness. At f/16.o the >>performance drops. >> The close-up performance ( 1 meter) is identical to the infinity setting. >> >> The Elmarit-M 2.8/28mm (#3793205) at full aperture shows a high contrast >>image with very fine detail crisply rendered. On axis over an image area >>0f 10 to 12mm diameter) the extremely fine datail is very clearly visible >>with some softness at the edges. In the field (outer zones) the contrast >>drops, and the outlines of large objects show a very faint colour fringe. >>Extremely fine detail is recorded with good clarity, with a slight >>fuzzyness at the edges. This performance holds into the corners where >>extremely fine detail is still visible, but with fuzzy edges. >> At f/4,0 the image crispens in the detail rendition. Extremely fine >>detail is now clearly resolved with great clarity and sharp edges and >>exceedingly fine detail is now crisply resolved on axis, with some >>fuzzyness in the far corners. >> At 5.6 the outer zones improve a bit, but the center is already past its >>optimum. >> Close-up performance is equal to the infinity setting. No decentring >>could be detected. >> >> The Elmarit-R 2,8/28mm (#3701134) is almost identical in performance to >>the M version. The R version exhibits slightly more chromatic aberrations >>and the performance in the field is a bit lower. Generally however this >>lens is equal to the M version. Close-up performance till 30cm gives >>excellent imagery comparable to the infinity setting. Again no decentring. >> >> Conclusion: the use of aspherics (two surfaces ) in the Ricoh is not >>automatically a 'free' ticket to best perfomances. We have been >>evaluating here absolute performance and on this quite lofty Olympic >>heights the Ricoh is clearly not as good as both Elmarits, which deliver >>superior imagery. To stay for a while in this comparative field. The >>Ricoh is better (by a good margin) than the first and second generation >>of the Elmarit 28mm M lenses. The third generation of the Elmarit however >>shows better performance in all areas, as of course does the current >>(fourth ) generation. Absolutely speaking: the Ricoh at 5.6 and 8.0 is >>almost as good (but not quite) as the Elmarit 's at 2,8. >> >> But we can also look at the performance from a slightly more casual >>perspective. If we assume that the Ricoh and Elmarit pictures will be >>taken on colourneg films or higher speed B&W films and enlarged to let us >>say the ubiquitous 20x25cm format, then the performance differences >>shrink. Of course on close scrutinization the overall softer rendering of >>the Ricoh will show. In the center area however the margin between the >>Ricoh and the Leica lenses is under these conditions is not that >>big.Stopped down to 5,6 or 8.0 you would be hard pressed to notice any >>difference. >> >> There is one area where the Ricoh has an advantage: the mechanics of the >>separate viewfinder. It is a solid chrome metal piece of work. Optically >>the finder distorts quite a bit: that mars the joy a bit. - -- christer almqvist eichenstrasse 57, d-20255 hamburg, fon +49-40-407111 fax +49-40-4908440 14 rue de la hauteur, f-50590 regnéville-sur-mer, fon+fax +33-233 45 35 58