My 2 Cents on Fill Flash

I’ve always tried to avoid using flash, but often I wish I had just a little boost to diminish shadows. I usually use reflectors, but that means carrying additional bulky gear. So, I’ve been experimenting with fill flash lately.

There are all sorts of formulas for adding just the right amount of fill light to an image. What I have found is that the best way to achieve well balanced fill flash is to start with a flash unit that will allow you to reduce the flash output by fractions of an f/stop. Reducing the flash’s power by 1/2, 1/4, and so on is not the same.

Image of Nikon SB-24 courtesy of www.mir.com.my

I started with a Nikon SB-24 and my F4. I set the flash exposure compensation on SB-24 to -1.7 (that’s almost, but not quite, 2 stops under). The F4 is set to aperture priority auto and away I go. It works really well, every time. I like the SB-24 very much and it’s the flash unit I go to if I need to be sure my fill flash exposures are perfect.

Hyde Street Pier, San Francisco. Nikon F4 with the SB-24 set for matrix Balanced Fill Flash with and -1.7 compensation ratio. Photo: ©2007 David W. Sumner

The only problem I have is the size and awkward balance of this set up. The SB-24 is big, and when it’s on top of an F4 the combination is top heavy and not too easy to carry around. The F100 is lighter and works perfectly with the SB-24, but hangs upside down if on a strap around my neck or on my shoulder.

I did some reading and heard some good things about the SB-23. I was able to find one at KEH for less than $40, so I ordered it. It’s very simple, small, light, and very, very energy efficient. It has only one switch and two settings: ON and OFF. I have found that it works best on my F100.

The Nikon F100 with the SB-23. Photo: ©2008 David W. Sumner

With the F100 I set the flash mode in camera (something you can’t do with the F4). I choose matrix balance flash and rear sync, and set the exposure mode to aperture priority. Based on my aperture selection the camera sets the shutter speed, calculating the correct ambient exposure. The camera also measures the flash out put and shuts off the flash when the “correct” balance of ambient and flash are achieved.

The Cable Car Museum. Nikon F100 with SB-23. Photo: ©2008 David W. Sumner

This combination works well, but is not as precise as being able to dial down the flash out put by 1/3 stop increments on the unit itself. However the SB-23 is so small and easy to carry, even mounted on the camera, it’s often worth the compromise. Just remember that with the SB-23 you need to par attention to the distance between you and your subject. In other words, don’t get too close. Otherwise the closer you get more you have to stop down your lens and eventually start using a tripod. (Most SB-23s you find will have a sticker pasted on top with a distance guide for various combinations of ISO and f/stop.)

Most people I’ve talked to or read tend to dismiss the “pop-up” flash units on newer cameras as pretty much useless, except for full on flash shots of the family at a picnic. But I don’t agree. I recently photographed the current exhibition of costumes at the Museum of Performance & Design using the Museum’s Nikon D80. I chose the D80 over using film because it allowed me to crank up the ISO setting as I moved around the gallery, in and out of various lighting arrangements, and it has a small on board “pop-up” flash that I can dial down to a -3 stop out put if necessary.

When shooting the costumes I set the camera’s ISO to 1250. The ambient exposure was f/3.5 (wide open) at around 1/20. In general the exposures were good but I could tell I needed a little boost. I popped up the on board flash and dialed in a compensation ratio of -1.7. That’s just what the scene needed. The flash was subtle but made an obvious difference in exposure that maintained the warmth of the ambient lighting while gently opening up the shadows. The gallery I was shooting is a big room. I was using a Nikkor 18-135mm DX at 18mm. The coverage of the flash was perfect. I’ve used the same set up in the same room during an evening event when the ambient exposure had dropped two stops. In that case I found that a flash compensation ratio of -1 worked best for capturing images of guest viewing the exhibition, (as long as they were not moving).

Gallery shot #1: Nikon D80 at ISO 1250 ambient exposure only. Photo: David W. Sumner/MPD

Gallery shot #1: Nikon D80 at ISO 1250 ambient exposure plus -1.7 Fill Flash. Photo: David W. Sumner/MPD

I have a Canon Eos Elan 7NE that has a “pop-up” flash and I use it the same way. It can be dialed up or down in _ stop increments. Not as precise as the Nikons, but I’ve found that dialing down to -2 gives me a good amount of fill without being obvious.

So for me a good rule of thumb for fill flash is to start with a composition ratio of -1.7 and if I’m at all uncertain try a few frames at -1.5 and -1. Of course, if I was shooting a fast paced event outdoors I’d leave it at -1.7 and shoot away.

If you’re experimenting with fill flash or have found a formula that works well for you I’d like to hear from you.

Here’s a link to an article by the late Galen Rowell on his strategy for using fill flash.