Fill flash with 1Ds and 550EX (e-ttl)

[Jonathan Wienke]

I would use shutter priority mode (since you have a 1/250 max flash sync), set exposure compensation to get the background right, then use flash exposure compensation to adjust the amount of flash fill.

[Gochugogi]

"To light a shaded face with a sunny background, which are good settings for metering and exposure. My tendency would be to use the aperture priority, meter the background, use auto exposure lock, frame and take the shot. I might use spot metering to make sure I meter on a good bright part of the background."

E-TTL flash uses Evaluative metering as the default metering no matter what pattern you select. The old lock-AF-recompose technique makes for poor flash exposure. Why? An E-TTL preflash is used to determine flash exposure a spilt second before exposure. It meters exactly where the active AF sensor is. If you lock-AF-recompose, the sensor will fall over something other than your subject, thereby over or under exposing flash. For example, if you recompose and the sensor falls on a black void, it will overexpose. There are 2 simple fixes:

1. Use AIM--i.e., let the fuzzy logic of auto AF sensor selection focus on your target. Flash exposure will be biased to your subject.
2. Don't trust fuzzy logic? Then use FEL to lock flash exposure on your subject.

[RNB]

It's a little embarrasing to admit, but I'm having trouble figuring out the proper settings and technique for using my flash with the 1Ds (which is probably the same as a 1D or a 1V). Specifically, my trouble is with fill flash.

To light a shaded face with a sunny background, which are good settings for metering and exposure. My tendency would be to use the aperture priority, meter the background, use auto exposure lock, frame and take the shot. I might use spot metering to make sure I meter on a good bright part of the background.

Pardon the newby question, but between FEL, AEL and some of the other gizmos, I am confused. I'd appreciate any advice. The manuals are confusing me here.

Thanks.

[englishm]

Since you are using the 550EX, you have the luxury of using high speed flash sync at any shutter speed.  Higher speeds decrease the effective range of the flash, but this is rarely a problem in fill situations.

If the face is turned away from the light with the sun providing highlights on the hair and shoulders, and the background is not overly light in tone, I usually set the exposure manually to about 2/3 to one stop over a sunny-16.  Set the exposure compensation on the flash to about -1 to 1 2/3 (I turn off the automatic flash reduction with the approriate CF), and shoot away.

If you prefer you could meter the background manually and open up a stop or so, if it is a light toned background (sunlit sandy beach for example), close down a stop or so if it is dark (shaded trees for example).  This will generally provide a subject background balance that appears natural to the eye.  But this is of course not a hard and fast rule, feel free to vary the compensation on the background to your taste.  You definately want to set the flash compensation to atleast 1 under, since the operative concept here is to fill but not to over light the face.

This is the type of thing where you just have to experiment a bit.  Any advice should be taken only as a starting point.  Differences in metering methods, personal taste, etc. will cause your mileage to vary.

You're fortunate in that you can immediately preview the results with your IDs.