Archived posting to the Leica Users Group, 2010/03/31
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]>David Rodgers wrote: > >>I always admired Leica lenses because they were extremely well built. >>When I set my camera down hard I took consolation in the fact that the >>lens elements were mounted in there rock solid. >> >>Perhaps that's why it's difficult for me today to warm up to a lens >>where the elements are moved around by who-knows-what kind of little >>mechanism. It's sort of neat that a little thing-a-ma-jig can determine >>whether or not -- and more impressively how much and what direction -- >>I'm shaking, and that it can quickly compensate for that. >> >>But again, I think I prefer that all elements be well cemented and that >>those that move are in helicoids machines to extremely tight tolerances. >>But that's just me. :-) > >It's not just you. I thought de-centering is one of the things we >wanted to avoid for consistent image quality from one edge to the >opposite one.. not to mention the additional internal reflections >caused by the IS (or VR) unit's several glass elements. When IS was >first commercialized, film was still king and mucking about with the >lens was the most practical means of accomplishing the goal, but >with a digital camera the sensor can be moved instead, letting the >lens do its optimum thing and leaving the stabilizing to the camera >body. > >Doug Herr >Birdman of Sacramento >http://www.wildlightphoto.com > Lens based IS compensation is still more effective than body based IS, and while lens based IS does introduce more air/glass surfaces along with more elements, that should also be the only additional consideration regarding decentering; ie, more elements, more chance of decentering. Depending on the general quality of construction, that should not be any issue in the end. Remember that body based IS also introduces extra possibilities for poor assembly or badly designed systems to compromise alignment. As mentioned before, when lens is locked down it only allows very high pitched frequencies to occur; older IS systems do not compensate for higher frequencies and can of themselves actually set up vibrations at those frequencies if they find harmonics in the lens/tripod system. In the 90's I switched from Nikon to Canon for a number of reasons. One of the things that decided me was Canon's introduction of IS; I got one of the first 100-400 IS lenses which made photography at 400mm hugely more successful, especially since I was using 64 and 100ISO transparency film. It's not a substitute for faster lenses, but rather a parallel approach and opens up a lot of options for image making. I have 7 or 8 IS lenses as well as P&S cameras with IS. I wouldn't want to not have that option any more. -- * Henning J. Wulff /|\ Wulff Photography & Design /###\ mailto:henningw at archiphoto.com |[ ]| http://www.archiphoto.com