The following Canon EOS 40D battery life numbers (how many photos can be taken before the battery power runs out) is extracted from the Canon 40D Manual and the Canon 40D Specifications page.
All figures are calculated based on CIPA (Camera & Imaging Products Association) testing standards (see the section titled “Standard Procedure for Measuring Digital Still Camera Battery Consumption” for more information), and assuming one of the following power supply conditions:
- One fully-charged Canon BP-511A 7.4V, 1390mAh Lithium Ion battery pack.
- With the Battery Grip BG-E2N or the older BG-E2 attached, you get the option of using one or two fully-charged Canon BP-511A battery packs, or six AA-sized batteries.
Viewfinder Shooting — Approximate Number of Shots
One BP-511A battery, with or without the battery grip attached:
- Temperature 23°C / 73°F, Autoexposure only (no flash used): 1100
- Temperature 23°C / 73°F, Autoexposure 50%, Internal flash activated and used 50%: 800
- Temperature 0°C / 32°F, Autoexposure only (no flash used): 950
- Temperature 0°C / 32°F, Autoexposure 50%, Internal flash activated and used 50%: 700
Two BP-511A batteries, with an attached battery grip:
- Temperature 23°C / 73°F, Autoexposure only (no flash used): 2200
- Temperature 23°C / 73°F, Autoexposure 50%, Internal flash activated and used 50%: 1600
- Temperature 0°C / 32°F, Autoexposure only (no flash used): 1900
- Temperature 0°C / 32°F, Autoexposure 50%, Internal flash activated and used 50%: 1400
Six AA-sized batteries, with an attached battery grip:
- Temperature 23°C / 73°F, Autoexposure only (no flash used): 400
- Temperature 23°C / 73°F, Autoexposure 50%, Internal flash activated and used 50%: 300
- Temperature 0°C / 32°F, Autoexposure only (no flash used): 200
- Temperature 0°C / 32°F, Autoexposure 50%, Internal flash activated and used 50%: 100
Live View Shooting — Approximate Number of Shots
One BP-511A battery, with or without the battery grip attached:
- Temperature 23°C / 73°F: 170
- Temperature 0°C / 32°F: 130
Other Battery Life Factors
In the 40D Manual, Canon advised that the battery life and number of shots decreases when:
- The shutter button is pressed halfway for a prolonged period.
- Autofocus is frequently activated without taking a picture.
- The LCD Monitor is used a lot.
- IS (Image Stabilization) on the lens is activated.
Some lenses draw more power from the camera’s battery during operation due to their physical (heavy lens elements that need more power to move) and electronic (type and technology of the IS employed) properties.