Hi, I am getting a bc error while shooting with eos-3 . This is an used camera that I bought several years ago from keh . I thought the problem was with the 2CR5battery and changed it . Will there be a problem if the battery is stored for a long time in the camera without usage or left outside the body for a long time? I get bc 3 error and sometimes it shows low battery . It happened with canon eos 400 mm f5.5 usm lens . I also use the canon ef 1.4 extender. I had similar problem with another lens. I also noticed that I had problem when shooting against bright light or against sunlight. I press the shutter release button, it opens and remains in position , and viewfinder remains dark. The shutter opens, gets stuck and does not return to normal . After switching off the camera , and changing battery , shutter closes but shot is ruined. I had similar situation with long lens too and I tried with different battery and I had same problem shooting against sun. I then switched off camera and then tried by switching from autofocus to manual focus and it worked normally. what could be the problem?