ho_co Posted November 10, 2010 Share #41 Posted November 10, 2010 Advertisement (gone after registration) ... My recent Leica experience reminds me of when I had cars from the VAG group.... Now, I drive Toyota.... There's the rub. More reliable, less expensive upkeep, but no fun to drive. Link to post Share on other sites More sharing options...
Advertisement Posted November 10, 2010 Posted November 10, 2010 Hi ho_co, Take a look here Focusing Metaphysics. I'm sure you'll find what you were looking for!
juergen Posted November 10, 2010 Share #42 Posted November 10, 2010 Oh, sure. Just curious, how many Toyota cars had to be recalled within the last year worldwide? If I remember correctly, that number was approaching or even exceeding 5 million. And now it is Lexus, too. Andy And the IQ and the Passo. I just read that this was the 146th. recall activity in the history of Toyota. Juergen Link to post Share on other sites More sharing options...
gyoung Posted November 10, 2010 Share #43 Posted November 10, 2010 Old lenses are made for film - film is imprecise compared to sensors. Old lenses have to be brought into the tolerances that are valid now - the old tolerances are too wide. Is this actually true?, If so there would be even more trouble with film, and it would be random depending on the position of the film in relation to the lens from frame to frame, or from one type of film to another. I know films differ in emulsion thickness, from probalby the thinnest Kodalith type to I expect Kodachrome was/is the thickest, but the front face of the emulsion should be pretty accuratley placed, especially with such a fine instrument as the Leica M bodies. What are the possible film register tolerances, and how is the sensor more accuratly placed? Link to post Share on other sites More sharing options...
christer Posted November 10, 2010 Share #44 Posted November 10, 2010 A trivial, but nonetheless real cause of focusing difficulty with Leica M is dirty rangefinder windows. Some people seem to think that the windows are clean when in fact the grease and dirt is just evenly distributed on the glass surfaces. Incorrect focusing is then interpreted as a fault caused by the camera... A few drops of 50-80% alcohol on an old piece of cotton cloth works wonders. Microfiber cloths are fine, but some alcohol from time to time cleans in a different way. Link to post Share on other sites More sharing options...
ho_co Posted November 10, 2010 Share #45 Posted November 10, 2010 ... What are the possible film register tolerances, and how is the sensor more accuratly placed? g, film has depth and the sensor hasn't. Leica had a long article on the effects in LFI some months back, probably in the heyday of the M8. Even if you missed focus slightly, the red rays, say, might be in focus in the red layer of the emulsion, so some part of the image would be sharp. This can't happen in a digital sensor, where receptors for all wavelengths are at the same depth. LFI even mentioned that the M8 was an excellent tool for discovering focusing errors, simply because of its sensor. Link to post Share on other sites More sharing options...
lars_bergquist Posted November 11, 2010 Author Share #46 Posted November 11, 2010 LFI even mentioned that the M8 was an excellent tool for discovering focusing errors, simply because of its sensor. Yes! "It's not a bug, it's a feature!" In the days when the universal accessory finder VIDOM reversed the finder image laterally (right-left), this was touted in the Leica promotional literature as a boon -- it made it easier to level the camera ... I bet that if the finder had made the image stand on its head, Leitz would have claimed that standing on your head was the most natural position for taking pictures. But seriously, it is true that film is more forgiving of focus errors -- not only because it has depth, but because it tends to "blunt" the most extreme edge contrast, smoothing the distinction between "extremely sharp" and "pretty sharp". This situation has been exacerbated (gee, I got that in!) because current M lenses are indeed capable of producing extreme sharpness. With a suitably fuzzy lens, the problem doesn't exist. The old man from the Age of the IIIa Link to post Share on other sites More sharing options...
luigi bertolotti Posted November 11, 2010 Share #47 Posted November 11, 2010 Advertisement (gone after registration) ... In the days when the universal accessory finder VIDOM reversed the finder image laterally (right-left), this was touted in the Leica promotional literature as a boon -- it made it easier to level the camera ... ... With a suitably fuzzy lens, the problem doesn't exist... The old man from the Age of the IIIa Confirm: with my M8 I'm more comfortable to focus the old Summarit 50 at 1,5 than my Summicron 35 asph at 2... Link to post Share on other sites More sharing options...
juergen Posted November 11, 2010 Share #48 Posted November 11, 2010 I bet that if the finder had made the image stand on its head, Leitz would have claimed that standing on your head was the most natural position for taking pictures. :D Juergen Link to post Share on other sites More sharing options...
jaapv Posted November 11, 2010 Share #49 Posted November 11, 2010 Is this actually true?, If so there would be even more trouble with film, and it would be random depending on the position of the film in relation to the lens from frame to frame, or from one type of film to another.I know films differ in emulsion thickness, from probalby the thinnest Kodalith type to I expect Kodachrome was/is the thickest, but the front face of the emulsion should be pretty accuratley placed, especially with such a fine instrument as the Leica M bodies. What are the possible film register tolerances, and how is the sensor more accuratly placed? Even - especially- with the thinnest film, it is impossible to have it flat in the camera. Link to post Share on other sites More sharing options...
JBA Posted November 11, 2010 Share #50 Posted November 11, 2010 I'm waiting for someone to mention the circle of confusion. Link to post Share on other sites More sharing options...
pop Posted November 11, 2010 Share #51 Posted November 11, 2010 I'm waiting for someone to mention the circle of confusion. Is that a synonym for the members of this forum? Link to post Share on other sites More sharing options...
scsambrook Posted November 11, 2010 Share #52 Posted November 11, 2010 Even - especially- with the thinnest film, it is impossible to have it flat in the camera. Indeed - often you can actually see the curve if you open the shutter and look at the film. But, why then do we not have the 'focus issues' with film that seemingly plague so many M8 and M9 users? And, slow, black and white films used with developers that promote the so-called adjacency effect do indeed provide high edge contrast - as did the Kodachrome emulsons. Sometimes it seems efforts are made to demonstrate that what are presented as problems with focusing digital M cameras are actually nothing new, but phenomena which have always been present but un-noticed. Whilst acknowledging that there have always been individual lenses with mechanical problems, I remain unconvinced that such was a general condition in the film era. Colour slides projected onto a 3-feet wide or larger screen through a Colorplan lens will clearly show focus errors, as will a print of 15 by 10 inches made with a Focotar or similar lens. I speak from experience of both. Focusing errors I certainly had in the past, but they were sporadic, the result of individual failures rather than a constant presence. The same applies to my M8. There clearly are problems with getting some lenses to focus correctly on the digital M bodies, particularly the very fast ones and those with 'floating' elements. Perhaps it's time to start asking ourselves - and Leica Camera too - whether the standards of precision needed to guarantee the high standards of uniformity essential to high speed lenses in complex mounts cannot now be maintained even in the relatively small scales of series production carried out at Solms. Link to post Share on other sites More sharing options...
jaapv Posted November 11, 2010 Share #53 Posted November 11, 2010 Because, as the film is curved, if will always be sharp somewhere, not neccessarily in the correct plane. Plus the edges of sharpness are by definition (sorry,no pun) more exactly defined on a sensor. There the pixels are arranged with mathematical precision, as opposed to a film which has a random distribution of the halide crystals, plus diffusion and refraction of the light in the emulsion layer. We can fight to the end of time about the amount of resolution of film vs. sensors, but there is no contest about the precision of that resolution. Link to post Share on other sites More sharing options...
lct Posted November 11, 2010 Share #54 Posted November 11, 2010 Yes, also we did not pixel peep the same way in the film days and fast lenses were softer than current ones by a significant margin. Even on digital sensors, little focus errors are more visible with the 50/1.4 asph than with the pre-asph 50/1.4 for instance, let alone the then 35/1.4 and its famous Leica glow. Link to post Share on other sites More sharing options...
ho_co Posted November 11, 2010 Share #55 Posted November 11, 2010 ... In the days when the universal accessory finder VIDOM reversed the finder image laterally (right-left), this was touted in the Leica promotional literature as a boon -- it made it easier to level the camera ... Lars, I had never heard that. It is positively brilliant! Thanks! Link to post Share on other sites More sharing options...
elgenper Posted November 11, 2010 Share #56 Posted November 11, 2010 ...In the days when the universal accessory finder VIDOM reversed the finder image laterally (right-left), this was touted in the Leica promotional literature as a boon -- it made it easier to level the camera ... I bet that if the finder had made the image stand on its head, Leitz would have claimed that standing on your head was the most natural position for taking pictures. .... IIRC, that´s exactly what happened when trying to shoot verticals with a VIDOM.... Link to post Share on other sites More sharing options...
lars_bergquist Posted November 11, 2010 Author Share #57 Posted November 11, 2010 IIRC, that´s exactly what happened when trying to shoot verticals with a VIDOM.... Yes, if you forgot to turn the eyepiece 90°. The VIDOM, and also the earlier "torpedo finders" from which it was developed, should really have rotated the entire finder picture by 180°, not only reversing it laterally but also standing it on its head -- just like the matte screen of a plate camera. But the eyepiece incorporated an image reversing prism that erected the image, but did not adress the lateral issue. The later VIOOH or Imarect finders had an extra prism, so that the image was correct in both dimensions. The old man from the Age of Funny Finders Link to post Share on other sites More sharing options...
gyoung Posted November 11, 2010 Share #58 Posted November 11, 2010 photographing things at close distances using large apertures is not something I usually do with the Leica, but as it happens I recently acquired a 135/2.8 Elmarit, very reasonably but 'in need of care and attention', following adjustment of the 'goggles' , thanks to DOUBICE and others for advive on this elsewhere on the forum, I did try some statues at about 15' at 2.8, as a rough test, seemed ok on m3 but varied results on m6. This I put down to 'pilot error' or the relative inadequacies of the 0.72 finder. The lens is away now for a clean etc, when it comes back I will do some tests, and also with my other lenses, although the only other 'fast' one is a non asph. Summilux 50. Link to post Share on other sites More sharing options...
Maarten Posted November 11, 2010 Share #59 Posted November 11, 2010 What Lars calls 'Mystery' or 'Metaphysics' is nowadays called Process. The process resides on paper and can be found in thick binders. The binders are used to populate the bookshelves in the lab. When the operator receives a lens calibration job, the process requests that he checks both the camera and the lens. There is no escape. It will take him 5 minutes to test the camera and to find out it's okay. Then he will be working on the lens. Once lens and camera are returned the camera is off (because of all the traveling), but the lens should be spot on. This process can be done in one day, or even a couple of hours. I am in the lucky circumstances that I can drive to my employers offices via a slight detour over Solms a couple of times per year. And Leica is small enough so you can actually speak to the person who is repairing your lens. As reported earlier the 6-8 weeks repair times are needed to send the stuff in batches to Solms. Nevertheless I assume Wil van Maanen will do an excellent job as well. Link to post Share on other sites More sharing options...
pico Posted November 12, 2010 Share #60 Posted November 12, 2010 Because, as the film is curved, if will always be sharp somewhere, not neccessarily in the correct plane. [...] Okay, I call. I cannot believe that Leica is using pre-digital metrics as a standard for their new lenses. It makes no sense whatsoever. Further, Leica's QC metrics, their standard, is entirely defective for the focusing of their new lenses. Why do people rise to defend poor quality? I've no idea. Link to post Share on other sites More sharing options...
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