Stuart's only had his Canon 5D mark ll one week and wants to explore flash, so he's come to Keith Robins Photography to get the low down!He used my Canon 550EX for this pair of snaps.
Placing the flash into the hotshoe we set the camera on to manual and the flash to ETTL means that no matter what he uses as the aperture the resulting exposures will be identical.
The flash is able to read what aperture Stuart has set on his camera and automatically sends out a weaker powered flash for the second photo where he used f8 instead of f16. He did this just to see if there would be any difference - there wasn't.
Even if he'd used a higher ISO setting the flashgun would still have picked this up and allowed for the more sensitive settings.The shutter speed could have been anywhere between 2 seconds and 1/200th of a second and it would not have made any difference to the exposure as shutter speeds have no effect on flash photos, as long as they stay below 1/200th of a second.
For the next challenge we tried a darkened room and used a pair of Miranda flashguns which someone had thrown out a few weeks previous.
(Took me a whole afternoon with a soldering iron to adapt them to work on my radio triggers.)
Both gunare at arms length, one behind my head and the other out of sight to camera right. The f14 was necessary due to both guns being permanenty set to full power manual - auto doesn't work when there are two guns facing each other. I also needed to place a thumb across the flash window as a light modifier on the gun lighting my face, which means the one behind my head shows a little stronger.
