I have found that the battery life of DSLRs is often denoted in terms of possible shots rather than in running time (e.g. according to snapsort, one battery life on a EOS 70D is enough for 920 shots vs. 1100 shots on a 40D). This got me thinking as to what are the main sources of power/battery drainage on DSLRs (specifically, Canon EOS cameras), and what can in turn be done to increase battery life.
- Apart from taking a picture, what are the functions/actions that drain the battery the most and how do those compare to the power reqired for taking a picture? (I'm especially interested in any setting/function that will have a significant impact on battery life; for example, the image stabilisation function on some ES-F lenses? Continuous focusing using AI Servo AF?)
- While I'm out taking pictures, is it 'worth it' to turn the camera off in between shots (assuming the intervals will rather be minutes/tens of minutes than hours)? Or is the power consumption while the camera is turned on but not taking pictures negligible?
- How big an impact does the LCD screen have on the battery life? I assume using the Liveview instead of the Viewfinder continuously will drain the battery faster. However I usually use the Viewfinder and have only the info display turned on (the one where I can access the quick settings). Does this drain the battery considerably as well (i.e. is it wort considering turning it off entirely)?