Mirror lock up

[glenafton]

I have just bought a book by David D Busch (Canon EOS Rebel digital photography) to help me use my 550D properly and improve my technique. In the book David points out that the reflex viewing mirror can cause a slight vibration in the camera. As you probably know I like IR photography but cannot afford a dedicated camera so I use my 550D with a Hoya R72 filter. I use a tripod and the RC-6 to help eliminate vibration. The question is should I also lock up the mirror or can I just leave well enough alone?
Glenafton

[Sushigaijin]

Mirror lockup is most useful in medium-long exposures. The range is somewhere between 1s and 1/4s. Any shorter and the amplitude of vibration isn't enough to effect the photo, and any longer the duration of the vibration is insignificant to the exposure length. If your exposure doesn't meet the criteria, it can't hurt, but it probably won't help either.

[armando_m]

I have used it when taking a photo with a 300mm zoom + 2x teleconverter + wimpy tripod, it did help to get a better image

[OldClicker]

I would guess that your shutter speeds are way to long to make any difference. - Terry

[Greg McCary]

I would use it. I have an E3 and live view is basically the same as mirror lock up. One tiny vibration on a long exposure kills the shot.

[freygr]

Mirror Lockup, Use it with long lenses, very long exposures unless it's a very long lens (telescope) the mirror lockup or not the duration of vibration will not affect the image.

With wide angle lenses it's no a pressing issue unless you are doing micro-photography, then use mirror lock up if you are having movement problems.