Dan,
I went through exactly the same thing a few years ago. This is back to basics stuff that puts the user in control (not some flakey matrix metering slash TTL-BL metering algorithm). I still use the described settings and techniques exclusively when I have a flash attached. I only scratch the surface here.
The settings that I use are manual
mode, spot meter, AE-L set to FV Lock, Flash to TTL. I use the same camera setup for all flash photography – indoors or outdoors.
The first thing that needs to be understood is tone vs EV and that exposure compensation is not about adding or subtracting light, but telling the camera where to place the metered tone in the histogram. Meter from mid grey, dial in 0 compensation to tell the camera to put it in the middle. Meter from black, dial in -2 (varies with camera DR) to tell the camera to put it at the bottom of the histogram. +2 (ish) for white.
Tip: The average of the RGB values for colour is equal to the average of the RGB values of grey when metering. eg RGB 28,128,228 is equal to 128,128,128 in terms of exposure - both are 0EC.
NC still has one of the best tools for examining and learning exposure. It is that small dot that moves up and down the curve on the curves palette. In a correctly exposed image it will do a good job of showing the exposure compensation required if the image was spot metered from the tone under the cursor. X-axis is EC. Have a play with a grey scale, a MacBeth colour checker and some correctly exposed images.
Flash metering with TTL is the same as ambient metering. They both use the same metering system. It is important to understand when using flash that there are two elements in play… flash and ambient.
The technique that I use in
moderate lighting conditions:
Set flash EC for the tone that I will be metering from (fair skin is usually in the 0 to +1/3 range).
Set the shutter speed and aperture using exactly the same point. Normally I will use a EC 1/3 to 2/3 below the FEC. This is normally done for separation of subject from the background. This is just subtraction – whatever the FEC, subtract the desired amount of “fill” to get the ambient EC. FEC minus Fill equals Ambient setting.
Focus and set FV Lock on the metered tone.
Compose, focus and shoot.
The technique that I use for high contrast situations (bright background):
Same as above except that shutter and aperture is metered from the background – blue sky should be blue… not white.
Notes: Manual
mode is important to stop shutter and aperture from changing.
For white weddings, it is important to check that the brides dress does not fall outside of the cameras DR. Use the spot meter to check it.
Fill of (say) 2 stops or more is not fill – that is straight flash photography… ambient will have little affect.
Use gels on the flash to correct for ambient lighting.
If it is necessary to dial in excessive amounts of flash EC to get the image right, something is wrong. Check your settings, metering and technique.
ISO is set based on ambient conditions… I use fast lenses and ISO values up to 400. That is generally enough for me.
People shots are the easiest to spot meter. Make yourself familiar with EC values for a range of skin tones...
No recipes or chimping here….
Cheers