Butterfly Lighting - Again

I believe that blogging has changed how we view the progression of our educational milestones. Books, as we knew them, documented our personal explorations spread over an extended period of time and are then compressed between the front and back covers. When recalling a sequence of events that lead to that light bulb moment, it is easy to skip the inevitable trials and errors and go straight to the epiphany. On the other hand, a blog entry is often created in the moment of inspiration, and can be revised quickly and with relative ease. As a result, my blog, like my life, is subject to change as today's ideas and beliefs transform themselves into tomorrow's axioms and facts.
 
My photographic experiments often include lighting faces that are wearing glasses. This is particularly convenient, since I've been a qualified model since the mid 1950's. In a nutshell, butterfly lighting works well in this situation. By keeping the Key Light (the one that casts the shadow) and the fill light (the one that puts detail into the shadows) well off the axis, there is less light to reflect back from the center of your subject's eyeglasses. You may see the hint of glare at the top edge of my glasses, but this blends in with my eyelids and is therefore less noticeable. Keep in mind that this glare is actually the reflection of the ceiling, illuminated by my on-camera bounce.

Left: Flash Tube uncovered;    Center: Flash Tube half covered;    Right: Flash tube three-quarters covered

Controlling Output: Arcane knowledge abounds. Back in the day, flashes often had a single output level: Full.When working close to our subjects, we commonly reduced the practical output by partially covering the flashtube with our fingers, the more fingers, the less light output. This was fine when the camera was mounted on-camera. But because the Nikon SB-30 has an SU-4-type remote triggering capability, something besides fingers would be needed if it is used off-camera. I decided to leave a piece of gaffer tape on the back of the flash and use it to provide as much coverage as the situation dictated. See the above tryptic.

Post Script: The flash tube in the right image IS correctly covered. The bright portion that you see to the left of the gaffer tape blinder is decorative, and not part of the flash tube. 

Big Catchlights: In an earlier post, I used some Tupperware and a cookie sheet to bounce light on to a hardwood floor. Looking back, it would have been faster to simple place the SB-30 on the ground facing the subject, and placing a Zumbrella, or similar shoot-through umbrella, between it and my subject's face. I still get the low angle necessary to eliminate glasses-glare and a much larger light source, but gain a measure of speed and simplicity in the setup.

This is photo of a typical shoot-through umbrella, placed on a linlinoleum floor about 3 feet in front of me. The SB-30 is hiding underneath, and is triggered by an on-camera (manual) speedlight bounced off of a very high ceiling. You can see how this would provide a large catchlight and a soft fill light from below, the reasons one goes to butterfly lighting in the first place. Again, this is an easy and effective setup if your main camera-mounted speedlight is providing a bounced key light from a nearby wall-ceiling juncture. If you're finding that the fill is a bit too strong, just cover a portion of the fill light's flash tube with gaffer tape, as I did here. 

Reminder To Self: This technique only works for head shots, since the full and three-quarter length portraits will result in overexposure below your subject's waist.

My father had always told me to avoid multiple catchlights. This stands for reason: In a natural environment, there should be only one light source: The Sun. This portrait reflects this philosophy, as only a single catchlight can be seen in each eye. I continue to follow his advice, and will consider this "light under an umbrella" a useful technique for providing both catchlights and shadow detail, especially when my subjects are wearing glasses.

The SB-400 Does Something Useful, Part 2

I presented the theory in my last post that when (some) Nikon cameras are set to manual exposure, the Exposure Compensation Dial can be used to adjust a shoe-mounted iTTL speedlight. The goal was to provide a level of control over the speedlight when used as a fill light.

The Two Exposure Theory: Before proceeding, I'd like to present a model often used to explain the difference between ambient exposure and flash exposure. The ambient exposure, or the "available light", is set using a combination of exposure duration (shutter speed) and aperture size (F-Stop).  The Flash exposure is determined by the F-Stop only, assuming that the shutter speed you are using is within the normal synchronization range of the camera. In most Nikon DSLRS, it is 1/200 or 1/250 of a second. On the Nikon D50, D70/D70s, and D40, it is 1/500 of a second. However, the P7700 has a leaf shutter mounted inside of the non-removable lens, and can therefore synchronize at any speed, theoretically. There is a caveat to that, as we shall see.

Exposure 1 - Ambient : To test the theory presented in my last post, I mounted the P7700 on a tripod and positioned it in the shadow of a tree.With the ISO set to 200 and the aperture set to F 5.6, four exposures were made.

• Top left: 1/250 of a second
• Top right: 1/500 of a second
• Lower left: 1/1000 of a second
• Lower right: 1/2000 of a second

Exposure 2 - Flash : The shoe mounted SB-400 speedlight does not have a built-in exposure compensation dial. Instead, I'll be using the dial on the top of the P7700, as shown in my last post. 

In this series, the Exposure Compensation Dial was set to, form left to right, -3 stops, -2 stops, and -1 stop of underexposure. Notice the the sky stays the same, and the flash only illuminates the tree.

Now this is all TTL stuff, so the exposure represents the camera's best guess at what you want. It makes a judgement based on the relative brightness of the regions identified by the Nikon Matrix Metering algorithm, and it's usually pretty close.

In this next sequence, the Exposure (flash) Compensation was set, from left to right: 0 stops, +1 stop, and +2 stops. You may notice that the difference between the +1 exposure and the +2 is not as pronounced as one might guess. This may (emphasize the word "may") be cause by the flash exposure getting clipped at the exposure time of 1/2000 of a second. This is something that must be considered when using leaf shutters in these super-sync situations.

Depth Of Flash - Again: Remember that distance plays a part in the intensity of the flash. Nearer objects are "brighter" than those more distant. The shot above was made at 1/250 at 5.6, ISO 200, without flash. The concrete sidewalk is obviously darker than the vertical retaining wall.

For this shot, the flash was engaged. You can see that the shadows nearest the camera (lower left) are brighter than those farther away (upper right). Distance decreases intensity, as you can plainly see here.

What this proves is that there are some controls available when using the Nikon P7700/SB400 combination. Not that this is an ideal combination, but I think this may come in handy someday.