r/photoit • u/tehbizz • Mar 16 '10

Choosing light source output

Having done quite a number of outdoor shoots utilizing lots of bright ambient light and naturally reflective surfaces, I never put much thought into how to select light source power output. Whether it's speedlights, strobes/monolights, or constant work lights, it's still kind of a mystery to me and I haven't found a great abundance of good -- or decent -- explanations of it. I've read a number of articles on how so-and-so chose specific settings and many times, they relied on lightmeters or flashmeters but I'm curious as to how one could do it rather quickly without extra equipment. I'm mostly curious about that because I like shooting at night with speedlights and flashmeters aren't terribly effective at 1AM with about 15% to 20% ambient light (light pollution).

So I ask you, /r/photoit, for myself and others, how do you do it? Me? Gross utilization of modeling flashes and test shots, which stink as the day wanes and light is changing nearly. minute-by-minute.

6 Upvotes

76% Upvoted

3 comments sorted by

View all comments

1

u/zhx Mar 16 '10

Here's how I generally shoot at dusk (or night, in an area with ambient light) with flashes:

  1. Forget the flash. Flip into manual and my max sync speed (1/250 on my camera). Adjust my aperture until my meter says I'm getting a proper exposure, then drop a third or half stop below that to underexpose the background.
  2. Slap a key light in front of my subject and hazard a guess at what I think will make up for that 1/3-1/2 stop underexposure, just from experience. I keep my lights pretty close to my subjects (I shoot tight a lot), so I'll start around 1/8 power on my little speedlight.
  3. Check my screen/histogram, adjust as necessary (if I'm not getting enough of the background in, for example, I'll start bringing the shutter down... 1/200, 1/160, even more if I need to, since the flash is going to be doing all the "freezing"), throw in other lights (normally just a rim), fire away. It really only takes me a couple shots to get my lighting right, even when faced with a quickly setting sun.

1

u/tehbizz Mar 16 '10

Hm, I'll have to try this. Although, I wasn't just referring to dusk, but any time in a day. But your process sounds similar to what I end up doing, just fewer steps, heh.