P#22 Q5: Your Recipe for Successful Photography Includes Flash Compensation

The Magic Ingredients

John Siskin: When you're talking about fill light, think of it as a cake recipe. You take the existing recipe and put rum in it, then someone decides it's a better cake because of that. When you're dealing with fill light in outdoor photography, you're taking an outdoor shot and adding light to it in an effort to make the shot better. This is generally called flash fill.

I use the word strobe a lot. I don't use the word flash, except in situations that are old enough that we're actually talking about flash bulbs. We've been using fill light since people were working with flash bulbs.

What happens is you put a little bit of light into a shadow and it makes a big difference. You put that same little bit of light into a highlight area and it makes no difference. I could do the math on this but I'm sure we'd lose half of your listeners.

Audri Lanford: We might want to skip that.

John Siskin: I like to avoid doing the math on podcasts, but I have to admit that the math is compelling. All you really need to understand is that if you add light, it's going to affect the shadows more than the highlights -- a lot more.

You bring in a strobe and you point it at the subject. You're going to have light coming into the shadows. If you've got a low-power strobe, you don't have to worry about it -- you just use it and make sure your shutter speed is below the sync speed. If, however, you have an SB800 or a Canon 580 or a similar camera, then you've got to balance the existing light and the daylight.

Nikon cameras have a flash compensation dial. Same thing exists on a Canon but I don't remember what the name of that is. It allows you to balance the strobe to the existing light so you can take the flash compensation dial and turn it to a negative number -- negative one or negative two.

This means that the strobe is going to be one stop under the existing light or two stops under the existing light. All those nasty shadows that we talked about at noon suddenly are not as deep a shadow and the picture begins to work better. You can do this automatically. Canon will do it for you.

You can also use a diffuser with it and that will help a little bit. Just make sure you don't lose too much light in the diffuser. Those suck up light and you won't get enough on the subject. You need to check your LCD or your proofing method on your camera to make sure that you're getting enough light.

A lot of times people will grab something like a LumiQuest and try to work outdoors. You'll be working at an f-stop of f13 or f16 or something similar in order to get that shutter speed where you sync with strobe. Suddenly you need an awful lot of flash to make any difference at all at f16, so the diffusers can be a problem in that situation.

Audri Lanford: You know, it's really interesting. About a year ago I used the fill flash outdoors at a negative one type setting. We were shooting birds in a bird aviary. The difference between the photographs we took without it and with it were totally night and day. It was just unbelievable.

John Siskin: It's darn near miraculous.

Audri Lanford: When I came back, we were looking at our histograms, but it wasn't until we came home and looked on the big monitor and really saw the images that we realized how great they were. It was just fascinating.

John Siskin: One of the great things about shooting birds with a fill light is that it stops the wings.

You'll have an area where the wings are just stopped, but because the shutter speed is so long, you'll have the diffused wing too. You have the hard sharpness of the strobe and the softness of a longer shutter speed in the same image and it's really beautiful.

To Conclude

Using the right equipment and the proper techniques can make all the difference in the outcome of your photographs. John Siskin revealed that it's not necessarily the quality of the natural light that has the biggest impact on your photos, but the flash compensation and fill light you use to enhance the shot.