As with most things photographic, there are multiple ways to get there from here.

The simplest way to deal with your problem is to set the camera with some positive exposure compensation. (Take test shots and review the histogram to see how much compensation to add without blowing out highlights.) This doesn't avoid the exposure variation based on how much of the evaluative metering area the white dress occupies.

To reduce that variability you could switch to spot metering the dress with a larger amount of positive exposure compensation. Again, season to taste by reviewing the histogram.

Finally you could use an external incident light meter to determine exposure. The challenge here is that it's more stuff to mess with and you need to re-meter each time the lighting on the subject changes.

> switch to spot metering the dress

That would be my advice. In fact I pretty much use spot for everything anymore. If highlights are important spot them at about +2.5 and fix anything else later in C1 or PS.

- DL

Long ago, I probably shot close to 1000 weddings. I gave up on automatic flash and never looked back. Once you get the hang of it, it becomes very easy to manually adjust flash output and estimate the required aperture for ALL conditions. It just takes practice and understanding. For super critical use, you can simulate a scene in advance and test using an incident flash meter. Once you get this method in your mind, you will never go back to automatically measuring any sort of reflected flash.

You need to measure the intensity of the light to get a correct exposure. Its reflection is dependent on too many other factors - as explained above.

Nevertheless, I'll bet almost everyone will disagree with my manual approach and incedent meter reading. To each his own. I prefer doing the math and knowning whats happening.

So do you use manual mode on both the camera the and the flash or just the flash?  You'll have to bear in there with me as I am relatviely new to flash photography.

I have started photographing weddings and receptions for people and have noticed that my pictures seem to come out too dark even with a good flash on my 10D.  I have basically figured out that it is the brides white dress when it fills about half of the frame.  It seems the evaluative metering has problems with this.  Since I'm new to this type of photography I have not been able to figure out a solution.  Does anyone else have this problem or possibly a fix for it?

Thanks

Some wedding dresses contain a whitener that may flouresce under flash.  Same with some white shirts.  Even some hair shampoos and sprays (the head on fire is a problem).    Even if you meter correctly with the incident meter, you could go wrong.  The "add some exposure" may be too much.  Trial and error is best, but make sure the error isn't at the wedding.

Thanks for advice.  It looks like I need to dress my wife up in her wedding dress and start shooting.   :)  I've thought about using spot metering, but haven't got around to it yet.  So it looks like that is what I need to try.  Thanks again I will let you all know how it goes.

I agree with Bob that the manual metering is best for me.  A lot of wedding shots are "canned," so you know in avance the subject types (white, black, mix, etc.) and can pre-calculate and test for exposure.  Frequently the church or wedding location is available ahead of time so you can test.

The wedding day is usually too busy to do much calculating and metering.  Get as much done ahead of time as possible, including some of the canned shots.  A good assistant may be your most valuable tool.

Both.

On the flash, you set the manual power output to give you a guide number that aloows you to shoot at the desired aperture for the ISO speed you have chosen.

On the camera you set the aperture to match the guide number calculation for the flash power setting. Then, set the shutter speed to blend the desired amount of ambient light for the background (within allowed camera flash sync range).

Hope that's understandable. You need to understand the principle of flash guide numbers to do this - a very simple, but basic piece of understanding for a studio or candid photographer.

You may want to check out this article...

http://photonotes.org/articles/eos-flash/i...tml#guidenumber