> Right you are. I was going from memory and forgot about those, not > having used my 420 EX as a slave. I imagine it's clear I meant no > manual override controls. > > Now you bring up flash metering, and I just bought a meter that has > flash metering - a Sekonic L-508. I had been told that there are > problems with the E-TTL or wireless slave set-ups becuase of the > pre-flash triggering the meter. I was mostly planning to use the > flash metering function with my FD and medium format shooting. > > But for an experiment, and not really thinking about it, I tried using > the flash meter at rehearsal I was shooting the other night, and got > some results that got me wondering. > > I had my Elan 7 and 420EX on a tripod 20-30 feet from the stage. I > was using Supra 400, and either the 28-135 IS or the 75-300. Out of > curiosity I took a flash meter reading from stage using the test > button on the 420EX. I got 1/60 @ f/5.6. The camera's meter showed > 1/60 @ f/4. Not having any experience with flash metering, and being > unsure about the pre-flash, I decided to go with the camera's reading. > Then when i got the prints back, many of them were over-exposed, > probably by about a stop. It made me wonder if I should have shot at > the meter's recommended EV, although I realize there are other > possible explanations ofr ther over-exposure. > > So one question is does the 420EX fire a pre-flash when using the > test-button? Also what is the relationship between the camera's > settings and the intensity/duration of the test shot? I'm trying to > understand the difference between the flash-meter's reading and the > camera's. > > And generally, what can anyone say about using a flash meter with > E-TTL flash?
Hi Ken, Q: why 1/60 f/4 on the camera vs 1/60 f/5.6 on your flash meter A: I presume you are using P mode (otherwise the question does not make sense). The 1/60 f/4 is ambient metering, so that the background does not go dark. Ambient metering is determined at half-press of the shutter button. Flash exposure is separately determined by E-TTL preflash when you fully depress the shutter button. For this example, I suspect the flash is being quenched one half stop short of maximum power. (i.e. Correctly exposed for f/4 instead of f/5.6) Q: why are some flash shots overexposed A: Did the "flash OK" light show for all of your pictures? If so, there was a problem with inappropriate FEC. If not, could it be that you use the central AF point for focus-lock and recompose, WITHOUT using FEL. Again from my experience of E-TTL, the following appears to be what is happening: E-TTL flash metering is a VERY narrow spot. In my experience, it is necessary to have the subject spot metered directly over the AF point (1 cell out of 35 on the Elan 7E). If the selected AF sensor is pointing into blank space (e.g. Back of stage) at the moment that you fully depress the release button, the flash meter will register potential underexposure, and will dump the condenser into the flash tube for maximum power. The "flash OK" light will NOT glow. So, if you MUST use the central AF sensor (e.g. For non ECF users), then you *MUST* use FEL religiously. Even if you select Manual Focus, flash metering appears to occur only over the 7 zones corresponding to the AF sensors on the Elan 7E. For consistency, FEL is still the better method. Cheers Julian Loke * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
