Quote:
Originally Posted by duncan22
If a lens has IS it is recommended that it should be switched off when used on a tripod.
If you are shooting hand held and within a normal shooting mode where you are unlikely to get a blurry picture ie 250 sec and above are you better off switching off the IS ?
If the answer is it makes no difference then why switch it off when the camera is on a tripod or is it assumed that no one would use a camera on a tripod whilst shooting at 250 sec and above?
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To answer the rest of your queries Duncan. The effectiveness of I.S. and shutter speeds is down to:
a) The focal length of the Lens + crop factor of Camera.
b) The type of I.S. the lens has, e.g. 2 stop, 3 stop or 4 stop
c) The person's long lens technique
The recommendation for hand holding is at least the focal length + crop factor minus the I.S. stops.
Example: if you have a 400mm lens on a 1.6 crop body then you would be looking at 1/640 sec minus the I.S. factor, so if a 2 stop lens then in theory you may get away with 1/162 sec
BUT it still depends on the users technique.
I find that the longer the lens then the less reliable this formula is.
With lenses of above, say, 300mm you would almost always benefit from using a tripod regardless of the shutter-speed but the type of tripod and head you have also play a big part and a remote release would also help. When I use my 300/2.8 + 2x tc on the 7D I shoot on a tripod almost all of the time even if the shutter speed is up to 1/1600 sec or even more (with I.S. ON)
BTW, the reason why you should not use on a tripod with I.S. switched on with one of the lenses with an older type of I.S (e.g. Canon 100-400) is that the I.S. will still be picking up slight movements and will be fighting to correct this all the time which could result in blurry pics - the newer I.S. Systems are different.
Hope this helps.
13-12-10, 04:34 PM
