This evening during our WACC photo seminar we used flash to explore and emulate lighting conditions and how they affect a portrait. The four sample cases below simulate how direction, distance and size of the light affect the portrayal of facial features.

The first shot shows how on-axis (same direction lens is pointing) light flattens facial features. The next sample used bare flash in a close-up from-above pattern to emulate how overhead sunlight might affect a portrait shot. We get hard and deep shadows. The third sample shows what overhead, but highly diffused light does by bouncing the flash from the ceiling. With this shot we get soft shadows, but also unflattering shadows for the eye sockets. Finally, we brought light from a 45 degree angle to the camera and from above the subject. We get softer shadows and more flattering modeling of the face.

You will notice that for all these we used a fairly high ISO (2000), allowing enough ambient light into the shot to demonstrate how different light sources can mix and affect the overall color of the photo, and this is particularly apparent in the third sample shot.

Our thanks to our willing model for patiently putting up with all the strobing.

Continuing where we left off, we now take a look at how to capture art pieces with accurate color. To illustrate the problem, here are two attempts to capture a particular piece, one using flash, and the other ambient light. The flash exposure was taken with the flash pointed up, to prevent reflection from the canvas, and the flash unit was “flagged” to prevent direct forward spill of light, again, to avoid reflection in the paint. The ambient light sample required a long exposure (1/6 of a second), so use of a tripod proved essential.

Using flash

Using ambient light

Both of these images exhibit a yellow, overly warm color cast. The issue arises from the white balance used to capture these images. Some cameras do a better job than others auto-detecting the correct white balance, but this often proves challenging when light sources, say daylight and overhead incandescent lighting, mix. While it is possible to adjust white balance on the spot, a method I prefer for this type of work involves a reference shot using a gray card (like this one), as shown here.

Using a gray card

The gray card becomes a reference that, when used in post-processing, yields white-balanced color. You’ll have to trust me, but these next two corrected images match the original much better than the captures we showed above.

Flash, color-corrected

Ambient, color-corrected

And now you can appreciate why the “final product” we showed yesterday looked so “right.”

With cropping and resizing

Responding to a question about the SB-700 and whether it under-exposes when bounced, I related my experience that often bounced flash requires additional flash compensation to obtain a proper exposure. To explain this, I theorized that TTL may sometimes collect more light than is just reflected from the subject, and that this might explain why TTL in some circumstances, with light bouncing into the lens from sources other than the subject (i.e., the framed composition), would apply insufficient power — hence the need for additional flash compensation.

I decided to run a test to see if this theory made any sense, and since the original question also asked whether different flash units (Nikon SB-900 vs. SB-700) might produce different effects, I did a 3-way comparison between the SB-600, SB-700 and SB-900 units I have in hand. To see if I could trigger a condition where TTL would under-expose (i.e., under-power) the shot, I tried a variety of flash directions, including: straight-on flash, not a pretty picture; bounced up, from a tanned ceiling; bounced left, from a white door; bounced right, from a tan wall; and bounced back, at a 45 degree angle that would include some of the ceiling and some of the corner walls behind me.

To eliminate variables, I used the same fresh set of batteries in each unit, I kept the composition the same by mounting the camera on a tripod; kept exposure settings the same throughout at f/8, 1/125 sec and ISO 200; and ensured each flash’s compensation was set to zero (0) while operating in TTL-BL mode.

	SB600	SB700	SB900
Straight
Bounce up
Bounce left
Bounce right
Bounce back

As you can see from these results, exposure is fairly consistent (keep an eye on the whites and that gray card), except that maybe the SB-600 unit I tried is putting out a little less power when compared to the others. I would call that difference insignificant for most practical applications. However, while testing, I did note a couple of cases where significant under-exposure (i.e., lower flash power resulted). In each case, I realized that I did not have my eye against the viewfinder, and that since I was standing behind the camera, light was going into the viewfinder and affecting the overall TTL measurement. To illustrate, see the following example, where the middle exposure shows what can happen with an uncovered viewfinder, in this case, when the flash was being bounced back at a 45 degree angle. Could this be one reason why some report under-exposure when using TTL?

	Eye over viewfinder	Viewfinder uncovered	Thumb over viewfinder
SB900: covered vs. uncovered

But what about my theory that some bounced flash situations require additional flash compensation? The first set of results doesn’t seem to support it, so I decided to try a different composition, where the field of view was narrower, thinking that perhaps it would make a difference. It didn’t — at least not with this particular scene in front of the lens.

	SB600	SB700	SB900
Straight
Bounce up
Bounce left
Bounce right
Bounce back

Taking a closer look at this second set, it occurs to me that my impression (from experience) that flash positive flash compensation is often needed when bouncing the flash may be due to looking at a particular part of the scene, for instance, the vase in these sample shots, and seeing that in at least one case, it is in shadows. If that is what’s important to me in the exposure, I may well decide to apply positive flash compensation to get the “right” exposure, but that will come at the expense of the flowers (a.k.a., the highlights), which will tend to over-expose at additional flash compensation.

In addition, impressions of under-exposure (look at the case where the flash was bounced up) may result from the color of the surface from which the flash bounces. When compared to the bounce left samples, the bounce up samples look darker. The left surface happened to be predominantly white: hence the flowers seem brighter; whereas the ceiling is a combination of dark beams and light tan surfaces, turning the flower color less white. Again, if the flowers are what’s important in this composition, positive flash compensation might help with this, though some post-processing to mitigate blown highlights may be needed to complete the result. A similar argument can apply to the straight-on flash samples, which to the eye, appear as the most under-exposed of the lot, though I wonder how much that has to do with the color cast the lighting produced for those shots.

Finally, as an added bonus, these samples show how different choices of bounced flash affect the overall image. As light direction moves around, different modeling and dimensionality results.

A common query on Internet forums asks how fast of a lens and how high of an ISO one needs to capture family candids without the use of flash. May folks deem the latter intimidating (to family members), awkward and for the most part impractical, so I thought it would be interesting to show how flash would compare against wide open fast glass with high ISO in a lighting environment where one could possibly entertain such a comparison.

Since I did this handheld, the compositions won’t match exactly, but they will still be close enough to compare. See how you think things turned out here in this family play-night scene.

Nikon D700 @ ISO 3200 with 24-70 @f2.8

Nikon D700 @ ISO 800 with 24-70 @f8
SB-900 (TTL) bounced from camera right

Nikon D700 @ ISO 3200 with 24-70 @f2.8

Nikon D700 @ ISO 500 with 24-70 @f5.6
SB-900 (TTL) bounced from camera right

As you can see, these are quick grabs, the types of family, slice-of-life photos people want to catch without too much complication. The flash lighting isn’t optimal, but with a quick bounce, the flash doesn’t wash out and flatten out the scene, as direct flash would do. Notice also that when the flash becomes the predominant (main) light, shadow locations generally shift from the right side of faces to the left.

This is all a matter of personal taste; there’s no right or wrong here. The ambient lighting has a warmer, quieter feel to it, so it’s definitely capturing the moment more naturally. In this case, though, I prefer lighting the broad side of the face with flash, as opposed to the relatively harsher shadows that the ambient (lamp at camera left) light created. And this brings up a good point: when you shoot with ambient, you can’t slide or move the light around (not simply anyway). You are more or less at the mercy of the ambient light you have and will constrain your shooting angles accordingly. Depending on the situation, fewer options for shots may be available to you.

For full disclosure, I’ll also point out that for the ambient lighting shots I had to perform white balance correction to mitigate overly red/orange skin tones, and I also lifted the shadows a bit to lessen some of the harshness I noticed.

At any rate, there you have it: fast glass with high ISO vs. flash. You decide which you like best and which works for you.

A couple of months ago, I was comisioned to take this photo portraying hands belonging to the ladies of the family.

I accomplished the shot fairly simply, standing next to one of the subjects, aiming the camera straight down onto a dark cloth draped coffee table, and bouncing the flash off the ceiling.

As a follow-up, I was asked to take a more traditional group portrait, and for this I brought out my lighting kit, now including a 60″ umbrella softbox powered with 3 Nikon speedlights, placed at camera left and about 45 degrees to my subjects; a 43″ reflected umbrella at slight camera right for fill; and a reflector to the right of the subjects for additional fill.

I hoped all the equipment setup wouldn’t distract me from accomplishing at least one good shot, and I’m still evaluating whether I succeeded. I guess I’ll let the ladies decide which they prefer, or whether we need to try again.

I’ve been putting my DIY light box to good use lately to string together some simple compositions. In the past I’ve often wondered about paintings of still life, featuring fruit and other household inanimate objects. Now I find myself trying different lighting tricks with such easy to gather subjects. Here are some I hope you enjoy.