jaapv Posted July 27, 2013 Share #41 Posted July 27, 2013 Advertisement (gone after registration) He doesn't say anything about "mechnical tolerances," or any tolerances. I think this idea came from the forum, not from Leica.How do you think one achieves increased accuracy in a rangefinder without widening the distance between the windows? Link to post Share on other sites More sharing options...
Advertisement Posted July 27, 2013 Posted July 27, 2013 Hi jaapv, Take a look here M 240 focussing. I'm sure you'll find what you were looking for!
lct Posted July 27, 2013 Share #42 Posted July 27, 2013 By reducing the visual acuity value thus the critical base length of the rangefinder? Just a guess. Link to post Share on other sites More sharing options...
jaapv Posted July 27, 2013 Share #43 Posted July 27, 2013 There were no changes to the optical design. That would mean a change in the magnification, which not, as it would have lost the 28 mm framelines. Link to post Share on other sites More sharing options...
lct Posted July 27, 2013 Share #44 Posted July 27, 2013 Magnification is a factor of the effective base length, not the critical base length which is based on visual acuity, focal length, aperture, and circle of confusion IINW. Link to post Share on other sites More sharing options...
jaapv Posted July 27, 2013 Share #45 Posted July 27, 2013 Somewhat true, but given that the viewfinder is unchanged from the M9, it is not in play here. Acuity is not just given by these factors, but by light levels and vernier vision as well. Link to post Share on other sites More sharing options...
lct Posted July 27, 2013 Share #46 Posted July 27, 2013 ...Acuity is not just given by these factors... Which are the factors of visual acuity in your opinion? Link to post Share on other sites More sharing options...
jaapv Posted July 27, 2013 Share #47 Posted July 27, 2013 Advertisement (gone after registration) The eye and brain of the viewer? Link to post Share on other sites More sharing options...
lct Posted July 27, 2013 Share #48 Posted July 27, 2013 OK so if you use polarized sunglasses for fishing or driving by example, would you say that they may improve your visual acuity? Link to post Share on other sites More sharing options...
jaapv Posted July 27, 2013 Share #49 Posted July 27, 2013 Well, they reduce flare and enhance contrast, enabling to use more of the acuity inherently present. The resolution is determined by your retina, the flare and other optical effects by the eye and lens. Not different from a camera. Link to post Share on other sites More sharing options...
lct Posted July 27, 2013 Share #50 Posted July 27, 2013 By reducing light reflection, polar sunglasses do improve my visual acuity by a significant margin so i guess the M240 does the same by removing the external window of the rangefinder. Link to post Share on other sites More sharing options...
120 Posted July 27, 2013 Share #51 Posted July 27, 2013 How do you think one achieves increased accuracy in a rangefinder without widening the distance between the windows? Anything that helps distinguish between the two images in the patch will in theory increase the accuracy. In the case of varying brightness from 0.001 fL to 1000 fL, the acuity (of the average person) goes from 10 minutes of arc to 1 minute of arc. Link to post Share on other sites More sharing options...
jaapv Posted July 27, 2013 Share #52 Posted July 27, 2013 By reducing light reflection, polar sunglasses do improve my visual acuity by a significant margin so i guess the M240 does the same by removing the external window of the rangefinder. Which it didn't - it still has that window. The only window that was removed was the illumination window. Which was a matte grid that did not have anything to do with the focussing mechanism. Link to post Share on other sites More sharing options...
lct Posted July 27, 2013 Share #53 Posted July 27, 2013 ...The only window that was removed was the illumination window... Yes indeed what else? This has nothing to do with the focussing mechanism obviously. There is no evidence that the latter did change in any way. Link to post Share on other sites More sharing options...
jaapv Posted July 28, 2013 Share #54 Posted July 28, 2013 Exactly my point - the whole thing is the same, just better built. Link to post Share on other sites More sharing options...
120 Posted July 28, 2013 Share #55 Posted July 28, 2013 Exactly my point - the whole thing is the same, just better built. You have already commented "the brightness of the rangefinder patch is more controlled." I would have no idea about that. But apparently it is not the case that "Leica told us the manufacturing tolerance has increased for greater precision and easier focusing." Link to post Share on other sites More sharing options...
Jeff S Posted July 28, 2013 Share #56 Posted July 28, 2013 What we know... The rangefinder structure is unchanged from the M9, but its accuracy has been improved (per Stefan Daniel) Frame line illumination is now internal rather than through an outside window The rest is speculation, which some suggest involves build tolerances (issue #1) and/or improved patch contrast/visibility (issue #2). Some suggest that issue #1 is addressed strictly by virtue of issue #2. Whatever the cause, many cite an improvement in the ability to focus accurately with the new M. What I find most interesting is the lack of any promotion from Leica on this aspect, which I speculate may be due to their reluctance to impugn the quality of prior versions. Jeff Link to post Share on other sites More sharing options...
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