----- Original Message ----- From: Dr E D F Williams Subject: Re: Lens sharpness vs. camera shake
>Considering these things I am amazed at how sharp > some of the pictures people take through long lenses at motor races, hockey > matches etcetera actually look. I actually discovered that I could handhold the 400mm lens with my elbows braced on the hood of my truck steadier than the tripod could do the same thing. Mirror lock and finding some way to dampen shutter induced vibrations (even holding the tripod yoke with your hand will help) is pretty much the only way to do it. Shooting at 1/8 second or longer is often practical, but you need to be dealing with static subjects. With large format, 1/8 second is considered a very fast shutter speed, several seconds is more the norm, so it can be done in the right situation. A monopod is a pretty good device, as the camera still needs to be held. This dampens a lot of the vibration, and can help. Note, the 1/shutter speed rule applies to long lenses and monopods, as far as I am concerned. Regarding your Sigma 400mm, do you have a filter on it? I recall a couple of years a go, Shel was testing one of Pentaxes long lenses, and he was having sharpness problems. After ruling out everything else, he pulled the UV filter, and that seemed to solve the problem. William Robb
