The Nikon Speedlight SB-900; Nikon’s Flagship Strobe Gets Bigger But More User-Friendly Page 2
I skipped all the other custom functions and went straight to the one that caught my eye, the one governing light distribution. Not to be confused with the camera’s metering patterns, notably center-weighted, the SB-900 lets you control how light is spread out—beyond zooming the head. Illumination patterns are “center-weighted,” “standard,” and “even” (an icon in the display shows what’s in effect). This is a feature I haven’t seen before.
I was impressed with the SB-900’s performance overall. This shoe-mount strobe is indeed a powerhouse. I thought that its size and weight would keep me from using it, but I found myself taking it everywhere and using it constantly. It made the grade with a wide range of subjects, from statuary in cathedrals to outdoor sculptures, from window displays to stained glass windows, with people and nature. True, I do lament that not all functions are supported on my D300. But I’m pretty sure my next Nikon D-SLR will be a perfect match, and my mouth is watering at the thought of that dynamic duo working together in the future.
Here’s how illumination patterns work on the SB-900. Since my camera is DX (APS-C) format, that’s what the following data is based on.
Setting the Nikon D300 to ISO 400, the SB-900 display shows an effective flash range (DX format), as follows:
• At the 200mm setting on the 18-200mm zoom: even light pattern: 2.8-44 ft; standard light pattern: 2.9-45 ft; center-weighted light pattern: 2.9-45 ft.
• At 18mm (same lens): even coverage: <2-19 ft; standard coverage: <2-24 ft; center-weighted coverage: <2-27 ft.
So, from the data based on the stated guide number, you can see the effect is barely noticeable in the telephoto range, but fairly marked at wide-angle settings.
In actual usage, when I popped the flash against a white wall (flash seated in hot shoe), some vignetting was evident when the dispersal pattern was set to the center-weighted position, with the lens at 18mm. It was more pronounced with underexposure. At 200mm, I saw practically no difference from one pattern to the next.
In short, when shooting with wide angles, pay attention to this setting, especially when photographing groups of people or anything that needs to be evenly lit—use the even or standard setting. For portraits of individuals or couples, where the subject is more or less centered in the shot with surrounding space, the vignetting may help to frame the subject—use the center-weighted setting.
Exposure Compensation And Fill Flash
There are several things you should be aware of when using flash compensation and ambient exposure compensation (AE override) with the SB-900 for fill flash. In my tests, the subject was backlit by ambient light, frontlit by the SB-900 on-camera.
• Flash compensation is cumulative. If you set flash compensation both on the flash and on the camera, it adds up (whether you use plus or minus values). The flash compensation range is greater on the SB-900 than in camera (at least where the D300 is concerned).
• In every Autoexposure (Shooting) mode tested (aperture-priority, shutter-priority, program), the effect of using flash compensation (on-camera and/or flash) and ambient exposure compensation (AE override) together was also cumulative. I found that when compensating for bright ambient backgrounds, for example, with +1.7 EV with the camera set to center-weighted metering, I had to balance that with a reduction in flash output (with a negative compensation value, using -1.7 stops as a starting point, more or less to taste) to achieve the proper fill-to-background exposure. Keep in mind that…
• On its own, autoexposure compensation (AE override) affects the exposure governing both subject/foreground illuminated by flash and ambient background exposure.
• On its own, flash compensation affects only the subject/foreground flash exposure, but not the ambient background exposure.
• Note closely: when the camera is in Manual Exposure mode and the SB-900 is set to TTL, the effect of cumulative compensation (flash compensation + ambient AE override) that we noted earlier also applies.
• To find flash compensation values used, open the files in Nikon’s Capture NX2.
For more information, contact Nikon Inc. at: www.nikonusa.com.
Note: To see Technical Specifications for the Nikon Speedlight SB-900, go to the Instant Links section of our website at: www.shutterbug.com.