Hi, I recently purchased a used 50D (it was 8 months old, and about 5000 actuations). It works great, except it seems that sometimes it thinks the batteries are running low. The battery guage was blinking, and as soon as I turned it off, unscrewed the battery grip and then screwed it back on the battery guage is full! I didn't charge the batteries in between either? So - any guesses? I just updated the firmware to 1.0.7, it was 1.0.3. I don't know if there were any battery issues in previous firmware's. Thanks - this is my first post (of many) I think here. Seems like a great forum!