--- In [EMAIL PROTECTED], "F. Craig Callahan" <[EMAIL PROTECTED]> wrote:
> "C. C. Casparian" wrote:
> > From what I understand, camera shake has its most detrimental
> > effect in the 1/8 - 1/15th sec. range but 1/17 seems like a
pretty slow
> > shutter speed. This would seem to lessen the usefulness of an IS
system in
> > a wide-angle lens.
<snip>
> I believe what you're thinking of here is mirror "slap"--vibrations
> caused by the actuation of the mirror when the shutter button is
pressed. For
> reasons I would need to research to explain, these vibrations are
more of a
> problem at the shutter speeds you mention than at faster or slower
speeds.
That's actually a pretty easy one to figure out. Camera movement from
mirror slap occurs for a greater percentage of the exposure in the
1/8th to 1/15th second shutter speed range, which results in a
greater possibility of image blur from movement.
For longer exposures, as long as the camera stays stationary, mirror
slap vibration occurs for a smaller percentage of the exposure, and
for shorter shutter speeds, exposure is short enought mirror slap
vibration is not a problem. That's why mirror lockup is recommended
for that range of shutter speeds.
MadMat
*
****
*******
***********************************************************
* For list instructions, including unsubscribe, see:
* http://www.a1.nl/phomepag/markerink/eos_list.htm
***********************************************************
