Halle,\n\nI have a recently bought a Canon EF 70-200 2.8 IS lens and I think I'm\nencountering problems with this lens. When shooting at concerts, after\ntaking a photo, my EOS3 sometimes will not drop down the mirror and block\nup. When looking at the LCD-display, it announces that the batteries are\nempty, but they're not. I have to turn off the camera and then turn in on\nagain. After that it runs perfectly again.\n\nThis problem only pops up with my EOS3, my EOS33 has not yet had this\nproblem, but it's nog used as frequently as the EOS3. Other lenses on my\nEOS3 (the 50mm, 24mm and 100mm) dont't block the camera.\n\nUsually this happens once at a concert at the most (sometimes not at all)\nand it's only annoying, but yesterday, within 20 minutes, it blocked up\nthree times and about two times in the whole time thereafter.\n\nI'm trying to isolte the problem, as I can't (well... don't want to) turn\nin the whole set for repairs.\n\nI'm using the PB-E2 on combination with the EOS3 for better grip and so I\ncan use penlites. Could this couse the problem or could it be a combination\nproblem between lens and camera?