Metering Help with 10D and 580EX

I've got a 10D and just recently purchased a 580EX Speedlite to go

with it. The flash is great, as it should be for the price, but

I've got a question on metering.

 

I've read the entire series here:

http://www.photonotes.org/articles/eos-flash/

 

However, I'm still missing something. When in AV, TV, or M modes it

seems the cameras metering ignores the fact that I have a flash

attached. For instance, I was taking some test shots in manual and

set the shutter to 1/60 and f/8.0. The cameras meter told me I was

about 4 stops too dark to take the shot, however the shot came out

pretty close to accurate according to the histogram and looked good

visually.

 

My question: Is there a way to know via the cameras metering system

when a shot will be correctly exposed with the flash attached or is

it guess work/calculation?

 

Thanks in advance,

 

-J. Orrand

The 10D's meter and the 580EX flash are completely separate.

 

Shoot in Manual mode and the flash dominates the scene and is one of the recommended routes. Works great indoors and even with a diffuser or bouncing.

 

Shoot in Av mode and it becomes just a fill flash -- you has BETTER nail the exposure in Av mode, good luck! I suck at that one.

 

In M mode I pretty much meter only for the background and let the flash fill the foreground. Works pretty well.

In Av and Tv aperture/shutter speed is based on ambient light, and the flash exposure is fill flash. In M mode, exposure is based on ambient light, so you can underexpose ambient exposure and obtain a proper flash exposure. I use M mode indoors and Av outdoors with flash.

In these modes the camera meters for ambient and displays this. The flash is metered during the preflash before the shutter opens. You can control the flash exposure compensation and the ambient separately. I usually shoot in manual for flash illuminated photos but you can set Av and dial in ambient exposure compensation (to get a hand holdable shutter speed) and the use the flash to lift the subject from the underexposed background.

 

The cameras ambient meter will not help you determine whether the exposure will be correct since it is metering ambient light. The only feedback about flash metering you can get is if you use FEL and see the lightning bolt blinking then you have insufficient flash power to illuminate the scene (according to the flash meter - which may or may not be right).

Thanks for the explanations. I understand how this works now and will have more successful shots as a result.

 

Thanks again!

 

-J