Flash exposure memory is a recently added capability in the Canon flash system that makes it simple to select the right power and achieve consistent results.
When I run Speedlite workshops, one of the most common questions from workshop participants is;
How much flash power was just used?
Now with flash exposure memory I can answer them with the exact amount as opposed to apparently pulling a power setting from my experience that would be pretty close. Flash exposure memory is used so that when switching to manual flash, the last E-TTL flash power level is preset in manual. Obviously once you are working in manual flash you can adjust the power as you want, but also be assured that every subsequent exposure is going to have the exact same amount of flash illuminating it.
So shoot an initial shot with E-TTL then switch to manual and subsequent shots are all consistently exposed.
Speedlites that support flash exposure memory
Currently Speedlite EL-1, Speedlite EL-5 and Speedlite Transmitter ST-E3-RT ver2 provide the flash exposure memory feature. It needs to be activated in the unit with a personal function setting (P.Fn)
- Speedlite EL-1 – P.Fn 05
- Speedlite EL-5 – P.Fn 04
- Speedlite Transmitter ST-E3-RT ver2 – P.Fn 08
For all three devices set FEM to ON so that when the mode button is pressed and manual mode selected the last E-TTL setting is used as the initial values for manual mode. You will notice that the two Speedlites have a third option, ON / MODE ETTL <-> M for their personal function setting. When set to this moving the controller down toggles between ETTL and Manual flash modes, and other modes are not able to be selected.
Multiple off-camera groups
If you work with off-camera flash flash exposure memory has a neat little trick for you. When working with two or three groups flash exposure memory transfers the power of each group to the respective manual group. If group A in ETTL used 1/64 power, group B 1/32 and group C 1/2 then when you choose manual mode then these different powers levels will be transferred. There is one step needed, you have to enable the same number of groups using the ratio function in both ETTL and Manual flash modes. If you have two groups, A:B in ETTL and only one in manual then the group A value will transfer and the B value lost.
Advent Calendar of Tips
This year I’m writing a quick tip each day up until the 25th of December, here’s some of the others I have already posted.