How I Learned to Light

As I’ve told several people who’ve asked, I learned to light most of the photos you see in my Flickr pool by following the techniques outlined by Baltimore Sun Photojournalist David Hobby’s excelent Strobist blog.  He is a champion of using small shoe mount flashes off camera. An older post of his on a recent assignment to photograph a rock climbing center really does a good job of outlining how to set exposure when working with a flash in this manner. 

The challenge with working with a flash off camera is most of the time you can’t rely on TTL to set your exposure (and David will tell you you shouldn’t anyway).  Generally you’re going to be working with the flash and the camera in full manual mode, and the only communication between the two is the camera telling the flash to fire - so you are on your own.

It isn’t that hard.  The thing to keep in mind is shutter speed doesn’t have that much impact on exposure when using a flash. This is because the duration of the flash is orders of magitude faster than the shutter speed.  The exposure is then set by balancing aperature and flash power.  What shutter speed will do is let you control how much ambient light comes into play.  As David suggests, test the shot at the max sync speed of your camera (my 20D will sync up to 1/250 sec), set your aperature and flash power to where they need to be, then slowly ease down on shutter speed if you want more ambient light.  I use the preview and histogram on the camera to make sure exposure is right.  Take a shot, check the exposure, rinse, repeat.  Classic “chimping.”

The claim is eventually you just start to know what the settings will be by looking, but I’m far from there now and it takes me a while to zero in on the right settings.  Elsewhere, David suggests using you hand as a stand-in for your final subject.  He does this to maximize his time since often his subjects have little time for the photoshoot.  In my case, the subject is a usally a kid who has limited patience.  Pre-adjusting the shot like this maximizes my time before the attention span timer goes off. In the shot below, I got the exposure wrong a bit -

The hands are blown out (parts are pure white and the detail is lost), but I’m still happy with it.  There is minimal PhotoShop going on in this image.  I processed the RAW image in Adobe Camera RAW, then did the desaturation and a bit of levels work, finally a touch of sharpening.