Trouble Metering exposure

[KarinaS]

Hi everyone,
I'm hoping someone can help me. I need advice on metering in a really badly backlit situation. (Glass wall with full sunlight streaming through)I need to use flash so it shows detail of the bride and groom, it also needs to be a wide angle shot so I also need to make sure the detail of the inside the church is shown. Normally I would spot meter the skin of the bride, but their backs will be facing me, and I have no idea what I should be metering to gain correct exposure of the bride and groom Being a wide angle shot, I am concerned that even if I could expose for the bride's skin, being such a wide angle, spot metering wouldn't cut it as the facial area would be too small (as they are in the "distance")and I would accidently include the strong backlight in metering therefore obtaining a serious under exposure. How on earth can I meter accurately in this sort of situation, without pinning an 18% grey card on their backs! As you can tell , I am only fairly new to this!
Cheers, Karina

[chtgrubbs]

It's hard to say without seeing the setup. Is this a static situation which will allow you to take several meter readings and adjust or a candid during the ceremony? My method would be to use an incident flash meter and read the exposure for the window lit area that is brightest, read the dark area where detail is wanted and average the readings. Now it may be that the contrast range between the two areas is too great and some detail will be sacrifice on one end or the other. Adjust exposure retain detail in the area most important to you. Set the camera on manual and set your exposure determined by the incident meter. Put the flash on ETTL, have someone hold the flashmeter in the bride's postion and make an exposure. If the flash meter reading is the same as your base exposure then you are good to go. If it is off adjust the flash exposure compensation until it matches the base exposure. Voila, perfect balancing of flash and ambient light.

[SkipD]

In my opinion, using an off-camera flash (where the camera does NOT automatically control the exposure) is far simpler to deal with for the situation you describe than trying to deal with an on-camera flash. What I do is meter the flash at the subject and determine the necessary f-stop to get a good exposure of the main subject. Then I meter the background and figure out what shutter speed, married with the f-stop calculated for the flash, will give me the desired result for the background. It's extremely easy to get the desired results - usually with the first exposure.