Archived posting to the Leica Users Group, 2001/05/10
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]It seems to me (logically speaking) that if a perfectly focused (non-defocused) lens registers 100 lp/mm while on a tripod and only 20 lp/mm while hand held - to equal a defocused lens while on a tripod - if you hand hold the defocused lens (already at 20 lp/mm) you simply exacerbate the problem to worse performance. You certainly cannot get "better" performance than you started with. And you certainly can make it worse. A camera that is NOT nearly dead-on in focusing on the film plane, is simply going to, in all cases, give you WORSE performance than a camera the IS dead-on in focusing on the film plane. Why did Contax make the vacuum film plate? Why do MF and LF photographers constantly whine about film flatness? It is because the depth of focus parameter (where the lens focuses in relation to the film plane) is extremely critical. There is NO fudge factor here. And all of you Leica folks (me too) love to use your lenses wide open. f/2, f/1.4, and f/1.0 . Without precise focus ON THE FILM PLANE, you will get crappy photographs. You can get lucky. You can be off in your focusing and end up with the subject actually "in focus." But don't rely on luck. Make sure your equipment is built to do the job the way it is supposed to be done. This is where heritage and lineage plays an important role. The best fast precision lenses, on the best precision body. Pieces that actually were made for each other. An M3 lens works perfectly on an M6. And a new 90 APO/ASPH lens works perfectly on an M3. Heritage, lineage, history, and dedication is what makes it happen. So do you all still think that the flange to film spec, given to Erwin by Konica, is an error in engineering or done for a reason? Why won't Konica mate a Leica lens to a Hexar? Why have people attempted to have this done? I personally think this is a self answering situation. Jim At 10:07 AM 5/10/01 -0500, brougham3@yahoo.com wrote: > >So what's wrong with a visual inspection, then? If you can't see any >degradation, does it matter if it is present? From a practical standpoint, >what's it matter if the theoretical limit is 100 lp/mm for a photographer >who hand-holds 95% of the time? > >I ask because I seek your expert opinion, Erwin. I'm genuinely curious. >Does the defocus problem only really matter if you're using a tripod, slow >film, and trying to get close to the theoretical maximum? If hand holding >already degrades the image, how important does the mismatch between Leica >lenses and Hexar bodies become? > >Thanks!