Archived posting to the Leica Users Group, 2001/12/30
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]At 11:21 AM 12/30/2001 -0800, Henry Ting wrote: > but quite frankly mirror flapping is >only detrimental to closeup macro. Actually, the SLR mirror effects ALL photographs taken with a shutter speed between a 1/30 and 1/4 second. Not just close-ups. It kills the recording of fine detail. The reason is that the mirror hits the top and the diaphragm closes down just before the shutter opens. The mirror vibration is at its peak just when the shutter is open and the vibration lasts for roughly 1/30th second. Long enough to be fully captured with a shutter speed between 1/30 and 1/4 second. Shorter shutter speeds (1/60 and higher) are over before the vibration wave hits its peak. With longer exposures (1/2 second and longer,) the vibration is a very small percentage of the total exposure time and therefore is not recorded. Carbon fiber and wooden tripods will help dampen camera vibrations by absorption while steel and other all metal tripods tend to echo the vibration, and in some cases, amplify the vibrations putting the vulnerable shutter speeds all the way down to 1 second. The vibration wave sent through the metal tripod echoes back into the camera as a second vibration thus extending the vibration period. Throw a rock into the center of a small pond. The waves radiate out from the rock hit, toward the bank then echo back, from the bank, to the center, where the rock hit. It is the same in a metal tripod. The camera vibrations radiate out (down the legs) and echo back to the camera. This does not happen in either a wooden tripod or a carbon fiber tripod. If you have an SLR without MLU and want to photograph in the 1/30 to 1 second range, buy wood. Jim - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html