SB 800 Notes & Tips
Hi Phat,
Does your reference to "-1" mean that you adjusted the flash output level to -1ev? If so, that would be a clear cause of your underexposure.
Another cause could be your use of BL mode. In BL mode, the flash attempts to achieve proper exposure for your main subject and the rest of the image. Also, output compensation probably has a negative effect on BL mode. For a wedding, you're probably better off shooting in TTL (or TTL-FP) to be sure to get your main subject properly exposed.
I'm no lighting pro, but I've assembled some of my notes on SB800 use from the manual, Hogan D2H ebook, various forum posts and my experiences. FWIW, here they are.
Basic indoor settings: SB 800 and D2H in front Sync Mode, ISO 400 (640-800 if dark room), manual mode, 1/60, f/5.6-6.3, spot metering, AF-S (so flash only fires when focus reached), TTL mode, flash EV +.3, snap-on diffuser optional.
Check your histogram and try to "touch" the right edge for proper flash exposure.
Manually setting flash head: Press !!! and ! until correct focal length appears. The SB 800 auto zoom is calibrated to film, not digital. So, for full-sensor coverage and max. flash power, multiply lens focal length by 1.5x and subtract a small amount. E.g., set flash head at 85mm for 70-200, 40mm for 28-70, 28 for 20mm. To cancel auto zoom, hold SEL for 2 secs. Press - until m appears above ZOOM. Use side arrow keys to select on. Hold SEL for 2 secs. to complete setting.
Bounce Flash: Don’t use pull-down wide-angle adapter or snap-on diffuser (unless bright room with low ceilings);you'll usually need full power. Tilt Flash head up 90 degrees. Pull white bounce card (at top of flash head) to get highlights in eyes. Reduce aperture to 4 (you lose 2-3 stops with bounce flash).
Fill Light: Set camera in Aperture mode. Set flash in TTL (or TTL-FP) mode. Flash output level of –1.3 for people and –2 for objects in shadows.
Flip-down wide-angle flash adapter: use for 10-15mm lenses on current Nikon DSLRs; 14-23mm lenses on film SLR. Use for close-ups with flash head at 14 or 17mm.
Reset all settings to default: press MODE & ON/OFF buttons for 2 seconds.
Modeling Illuminator (gray button above LCD): press to see shadows cast by flash.
Glenn
