How long will an external flash battery last if power saving is disabled?
Asked 3/7/2022
3 views
2 answers
0
I need an external flash for a Canon EOS 40D camera trap. My current Metz 44 AF-1 goes to sleep and can’t keep power saving disabled in normal manual/TTL use, which is a problem for unattended triggering. I tested it in slave mode, where power saving is disabled, and the batteries lasted a little over two days.
I’m considering an older Canon Speedlite or similar flash that can stay continuously ready. In that always-on state, is battery life likely to be measured in hours, days, or weeks? Are there big differences between flash models, or is my slave-mode test a reasonable indicator of what to expect in manual/TTL operation?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
4y ago
2 Answers
3
Slave mode would be comparable to manual/TTL operation. It needs more logic than the latter, but since a flash capable of slave mode will use the same kind of logic for implementing manual/TTL, you don't save a lot.
The bulk of energy use will go into keeping the flash capacitor topped up, and that's just the same either way. The quality of the circuitry for that and the leakage of the flash capacitor may wildly diverge between different flashes, so it's perfectly possible that a smarter flash will use less current than a dumb flash, even if the latter has some advantage out the gate.
Originally by user102869. Source · Licensed CC BY-SA 4.0
user102869
4y ago
0
Generated from our catalog & community — verify before relying on it.
Your slave-mode test is a reasonable comparison for normal always-on manual/TTL use.
The main battery drain in a flash that stays ready is usually not the control logic, but keeping the main flash capacitor charged and topped up. Slave mode may use a bit more logic, but not enough to change the picture dramatically.
So if your Metz lasted a bit over two days in slave mode, that gives a useful real-world estimate for the same flash running continuously ready in manual/TTL. In general, expect battery life to vary a lot by flash design rather than by mode alone.
Key factors are:
- capacitor leakage
- efficiency of the charging/top-up circuitry
- overall flash electronics design
Because of that, different flash models can differ significantly. A more advanced flash could actually use less standby power than a simpler one if its circuitry is better designed.
Based on the information here, “days” is a more realistic expectation than “weeks,” but exact runtime is model-specific.
Recommended products
UniqueBot
AI4y ago
Your Answer
Related Questions
Can a Canon-dedicated Metz 44 AF-1 be converted to work with Nikon TTL by changing firmware?
What do I need to start using off-camera flash with a Canon 550D and Metz 44 AF-1?
How does TTL flash behave when the camera is in Manual exposure mode?
Why isn't the AF-assist beam working on my Metz 44 flash with a Canon EOS 650D?
Can a Canon ST-E2 let you adjust off-camera flash power from the 5D Mark III menu?