A friend recently suggested that putting their Sony A7ii camera in airplane mode improved their battery life.
I don’t have a Sony A7ii camera, but I do have an earlier model, the Sony A7, and the right gear to test this.
The setup:
- 2 multimeters, one measuring current, one measuring voltage
- External battery pack, 2x LG INR18650HG2 in series
- Sony A7 camera
Results
| Situation | Description | Power |
|---|---|---|
| Sleep | camera fully powered off | 39mW |
| Deep sleep | camera powered off for several minutes | 14mW |
| Viewfinder | viewfinder in preview mode, auto brightness | 3.30W |
| Screen, +0 | in preview mode with default brightness | 2.50W |
| Screen, -2 | min brightness | 2.43W |
| Screen, +2 | max brightness | 2.72W |
| Sensor off | Menu, in sensor cleaning mode | 1.12W |
| Airplane mode | 2.51W | |
| WiFi on | in WPS push mode | 1.63W |
| Continuous shooting | RAW, holding the button down | 4.59W |
| Shooting video | 60i 24M, AVCHD compression | 4.22W |
| Video playback | 1.79W |
Analysis
Airplane mode has no impact on power draw. When transferring files wirelessly, the camera shuts off the sensor and powers on the radio.
I was surprised to see that the viewfinder draws more power than the main display. The main display shuts down when the viewfinder is being used. It looks like this may be because the viewfinder is higher resolution than the screen.
The sleep power consumption is disappointingly high. New Sony NP-FZ100 batteries are rated at 16.4Wh, so you should get only 48 days of power-off time before the camera’s internal clock resets. I would have liked to see this power draw be in the microamps, ideally single-digit microamps.
Caveats
My test setup isn’t particularly accurate.
- There’s 0.66Ω of resistance in the cabling
- I only made one measurement for each circumstance
- The external battery pack I’m using has batteries rated for 20A of continuous current; the internal battery pack will have much higher internal resistance and more energy wasted, especially at higher power usages
- I did not do a factory reset beforehand, so some of my settings may impact the data
- Shooting different subjects has different power consumption
However, I feel like the quality of the measurements is sufficient for relative comparisons.