On Fri, 23 Oct 1998 03:23:51 GMT, fstev@~remove tilde~wco.com (Fred Stevens) wrote:
>In article <70of5n$qk$1@nnrp1.dejanews.com>, zinyflikop@sprintmail.com wrote:
>>In article <70nvip$557$1@news0-alterdial.uu.net>,

>>Try this. Take 300, 400 mm lens and take pictures with speed below 1/30 with
>>mirror locked and without lock. Compare result. You will see why you need a
>>MLU.

>Even with a rock solid tripod?

Maybe... A "rock solid" tripod probably doesn't exist (well, maybe
the big aptly-named Majestic...;-), at least for very long lenses.
Unfortunately, even (sometimes especially...) very sturdy,
cross-braced tripods resonate/vibrate when "struck" by the camera
shake when the shutter is released. A good tripod is one that is
well-damped (a good test is to lightly touch the top of a set-up
tripod while lightly striking a leg - most vibrate a v e r y
long time afterward...) - otherwise exposures made in the difficult
range of about 1/4-1/30 second will not be ideally sharp with long
lenses.