Pixel the Wonder Dog wrote:I have a 10D with the 550EX flash. So far I have only been doing some kid sport photography (hockey, gymnastics & baseball) but recently found myself in a portrait taking situation. I don't know a whole lot about it and I am having problems with the flash not setting off the strobes. Any ideas?
Also I found that the lcd on the 10D shows the shot much brighter what actually is. I have tried to set it accordingly but it is already at its darkest level.
Any advice is welcomed!
CW

I presume that "not setting off the strobes" means that you have some strobes set up and are asking the 550 to set off light slaves in the strobes.
If you have the 550 on E-TTL there will be two flash pops. The first one is to gather information on the subject's brightness or to inform other Canon flashes as to how they should work if you are using the Canon Wireless TTL. Then there's the second "real" pulse that comes out of the 550 to actually light the subject. This happens very quickly so you may have not noticed it, although I usually can see the first pulse though the viewfinder before the mirror pops up.
In any case the first flash pulse will trigger your light slaved strobes, even though your shutter is still closed. Then when the shutter does open the second flash from the 550 fires but it can't trigger anything since the strobes will be in the middle of recycling. If you want to use the 550 to trigger your light slaves, the fix is to use the 550 on a manual setting. On manual there is one conventional light pulse and this will happily trigger light slaves. I use a low power setting since I just want the 550 to trigger the slaves not provide much light. 1/64 power is a very nice battery conserving choice and I usually use a Sto-fen dome as well.
Trust the histogram NOT the LCD review screen. Ambient light, where your eye is centered and how you've set up the LCD display will all affect that image. I use mine only for checking expression and to see if there's any indication of highlight clipping. Yesterday I did a outdoor portrait sitting and the LCD reviews looked like the faces were hot. Not blown out, but hot. The histogram was right in the middle so I stayed there. The results were - at least exposure wise - perfect.
Trust your instruments (or replace your instruments) not your senses. Your histogram knows, your eye doesn't.
"There's never time to do it right. But there's always time to do it over."
Canon 5D, 50D; 16-35 f2.8L, 24-105 f4L IS, 50 f1.4, 100 f2.8 Macro, 70-200 f2.8L, 300mm f2.8L IS.