All this talk of sharpness has tempted to me to ask a question which is barely EOS related.
I have the EOS 300D, which has no mirror lock up (without resorting to hacked russian source code). My longest lens is the 100-400L. If I take a picture through the lens on my tripod at a slow shutter speed (with IS off) it always comes out blurry. I tried using a bulb so I wouldn't touch the camera, but it barely helps. I'm guessing my mirror slap is making the whole thing move. Either that, or the wind is doing it.
Your tripod is not rock solid. Are you mounting the camera on the tripod; or the lens on the tripod? Because the 300D is so light, it does a poor job of dampening things.
Ideally, you should have the biggest tripod you can carry, a very well dampened ballhead like an Arca-Swiss or clone, and something like a Wimberly Sidekick that will side-mount onto the lens itself.
Remember that your 400 is a 640mm lens on the 300D.
KN
-- Karen Nakamura http://www.photoethnography.com/ClassicCameras/ * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
