Archived posting to the Leica Users Group, 2003/04/06
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Dante Stella wrote: > When you use an FP shutter with speeds higher than the synch speed, > the shutter is always traveling at the synch speed (the slit narrows > but the curtains go at the same rate). The speed at which the shutter curtains is travelling is unimportant -- what matters is the amount of time which the film is exposed to light (and thus to the effects of camera shake). > So if you use, say a 500mm lens, and it is bouncing around as you hold > it, isn't the shutter recording little distortions a slice at a time, > even if it is at 1/500? Yes. Because of the greater magnification of the 500mm lens (compared to, say, a 50mm) same-sized displacements of the lens (as manifested through shake) will be more noticable at the same viewing distance of the final print. Thus, we use a shorter speed to reduce the magnitude of the displacement that can occur during film exposure. [Note: If we were to do the experiment of photographing the same subject from the same distance with a 50mm and 500mm lens, and then ensure that the final prints showed the same magnification (cropping the 50mm print and enlarging it to match the 500mm one) and viewing them from the same distance, I'm assuming that the evidence of camera shake would be the same (although some would be lost in grain). The angular displacement (shake) gets translated into the same linear displacement (blur) either by being a small blur on the negative under great enlargement, or a large blur on the negative under small enlargement.] > On an SLR with a 1/125 synch and lenses under 135mm, I have never > noticed any additional benefit to using speeds higher than 1/125. What are you suggesting here? I can't make sense of this. On the one hand, it would appear that the first statement is claiming that FP shutter speeds higher than the sync add no benefit. The second statement appears to be in favor of using a higher than sync speed. And this last statement appears to contradict that again. M. - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html