Sunday, August 22, 2010

First try with High Speed Sync & Wireless E-TTL

Nectar Time

It wasn't my goal to shoot butterflies. I was going to shoot high school girls volleyball.

Unfortunately, the online schedule lied to me about the location of the game I was going to shoot, leaving me 35 minutes away from the action 10 minutes after the scheduled game start.

Where I was, had butterflies. So I decided to do some experimenting with Canon's 'Wireless' E-TTL exposure system.

I say 'wireless' because usually wireless means radio waves. Canon's system uses coded light pulses. Cheaper, I guess, than adding a radio transmitters and receiver to the flash, and certainly free of government regulation, unlike radio waves. But line-of-sight wireless brings certain unique challenges, and outdoors it can be real pain.

E-TTL is Canon's name for through-the-lens flash metering. The quick-and-dirty is that the camera has flash fire a short preflash, reads the scene, and then tells the flash how much juice to put out when it actually takes the photo a split-second later. This is generally a good thing.

Lighting: Canon 550EX to camera left, using Canon wireless E-TTL and high speed sync. Exposure was set about 2 stops above ambient. Master flash on camera set to no exposure flash. Shutter speed set to 1/500th of a second.

The good: solid, consistent exposures, despite constantly changing subject to flash distances. Rapidly changing subject to flash distances are the sweet spot for E-TTL.

The bad: it was a bitch chasing down the butterflies and having to adjust the master flash to point enough towards the slave flash to trigger it. This one place where radio waves have it all over line-of-sight systems.

High speed sync allows the use shutter speeds beyond the nominal sync speed of the camera, but it kills the action stopping-power of the flash. It also reduces flash power, a fact that becomes important shortly.

I lost several shots to the combination of the breeze, the tight magnification, my own unsteadiness and the butterfly's movements. While 1/500th of a second may be a good base for stopping action, in this case I needed at least 1/1000 of a second.

Unfortunately, at 1/500th each shot was already a full dump from the speedlight. Going to 1/100th would have mean moving the speedlight even closer to the peripatetic butterfly, which was not going happen given that I was using a 300 mm at it's minimum focusing distance already.

However, when my other 550 gets back from the shop, I can set up two flashes on the stand, and that should get the power level up to where I can shoot 1/1000th.

Saturday, August 14, 2010

Just a Little Extra Light

Mustache and Steampunk

I'm wandering the halls of the North American Science Fiction Convention (NASFiC) in Raleigh, North Carolina, when I come across this fellow in a remarkable leather steampunk outfit.

This part of NASFiC was happening in the Raleigh Convention Center, which meant huge windows letting in lots of light reflected from the sky. The good news was that I had a decent supply of soft light to work with: 160, f/2.8 or so @ ISO 400.

That big hat, however, shadowed his face, which also dulled his eyes and the light was so soft it had very little shape.

So, I added just a touch of flash to add shape to him, and some sparkle to his eyes. I had my flash on a small light stand, activated by a radio trigger, off to camera left, with a small (really small) Lumiquest softbox on it. I had the flash dialed way back, so that I was getting about 1 stop above ambient. I aimed the softbox in front of him, so he was lit more with the edge of the light coming out.

While I like this, in retrospect I see a couple of things I could have done differently. First, I think a half stop, instead of a full stop, over ambient would have been sufficient. Second, a softer light source such as a bigger softbox, or an shoot-through umbrella, would still have given me shape, but with less harsh shadows. That little softbox was just too small and too far away to soften the shadows much.

Another option would have been to use a ball head to allow me to flop the flash over into a vertical orientation, which would have allowed me to cover the subject with the flash physically a lot closer, which would have increased the softening effect of the little softbox.

Sunday, August 8, 2010

Liven Up A Speech with an Off-Camera Flash

Eric Flint

Speeches are, visually speaking, boring. No matter how eloquent the speaker, it's still a guy speaking. Unless the speaker is incredibly dynamic, or the overall scene is wonderful, you're stuck trying to get something good out of a person speaking into a microphone, and likely hiding behind a podium.

So, there I am, trying to get something interesting out of Eric Flint's Guest of Honor session at the North American Science Fiction Convention. No podium, thank god, but basically it's just a guy sitting in front of a microphone talking. Eric's an interesting speaker, but he doesn't gesticulate wildly, or make funny faces when he speaks.

The stage lighting was 1/125, f/2.8 @ ISO 1600. If you shot him straight on, the background was OK, but if you moved around to the side to get angle that separated his face from the microphone, the backgrounds were absolute crap: piles of unused chairs, ladders and other equipment.

What to do? Flash to the rescue.

Since folks in the audience were popping away with their flashes from the front row, I figure no one would really notice one more, especially if it was tight and far away.

So I set up a a single Canon 550ex on a radio trigger on a light stand about 40 feet or more from the stage, well behind the audience. I put an 8-inch Honl snoot on it to control the spread and set the flash at 1/2 power. I placed the flash off to the side, so it would sculpt Eric's face if I shot him head on, and so it wouldn't catch the stage lighting supports and throw their shadow across his face.

That produced f/4 @ ISO 640, which on my Canon 50D produces much better images than ISO 1600. And when I moved around to the side, like in the shot about, it lit him dramatically and killed off that nasty background, giving me sweet, pure black.