Archived posting to the Leica Users Group, 2001/02/28
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]On Wed, 28 February 2001, Paul Chefurka wrote: > > Camera shake as I understand it has to do entirely with the angle of the scene that is swept by the lens while you're shaking it, multiplied by the magnification of the lens. I'd expect two 21's if different designs but the same weight to exhibit the same camera shake charactertistics when mounted on the same body. > Not quite. There's also moment of inertia to consider. A mass at a greater distance from the pivot point has a greater moment of inertia than the same mass close to the pivot point. A greater moment of inertia means it takes more force to generate a movement (in this case camera shake) than a system of identical mass but less moment of inertia. This is a big reason why it's far more difficult to hand-hold a compact mirror lens than a simple 2-element achromat like the f/6.8 Telyts. Consideration of the moment of inertial would suggest that slower shutter speeds are more stable with the retrofocus lens, not the non-retrofocus design as the LHSA writer claimed. Doug Herr Birdman of Sacramento http://www.wildlightphoto.com ___________________________________________________ The ALL NEW CS2000 from CompuServe Better! Faster! More Powerful! 250 FREE hours! Sign-on Now! http://www.compuserve.com/trycsrv/cs2000/webmail/