last update: 21 February 2002

  Nikon Speedlight SB-21A / SB-21B

The SB-21A and SB-21B are Nikon’s first macro Speedlights and were introduced in 1986. The difference between them is the controller unit: the SB-21A has an AS-12 for use with the F3; the SB-21B has an AS-14 for use with cameras with ISO hot shoes.


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GN: 43 (ft), 13 (m) (at 3.3 feet [1m] with both tubes firing)
Weight: 5.1 oz (145g) (main unit), 8.8-9.8 oz (250-280g) (controller w/o batteries)
Size: 5.1” (130mm) tall x 4.7” (120mm) wide x .8” (21mm) deep (main unit); 4” (100mm) wide x 3.5” (90mm) deep x 1.6” (41.5mm) tall (controller)
Power: four AA batteries
Recycle Time: 8 seconds minimum (full discharge)
# of Flashes: ~200 at full manual
Flash Duration: 1/2,000
Coverage: (65 degrees horizontal, 85 degrees vertical)
Case: SS-21 (or SS-17 for controller only)
Key Features: TTL flash control on most TTL-capable Nikon bodies; Full, 1/4, or 1/16 power settings. Left, Right, or both flash tubes can be fired. The SB-21 can synchronize with additional off-camera flashes, but the SB-21 must be the master flash. Comes with SW-8 Condenser Adapter for extreme close work, 52mm and 62mm mounting rings.

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Other Speedlights
SB-1, SB-2, SB-3, SB-4,
, SB-6, SB-7E, SB-8E,
SB-9, SB-10, SB-E, SB-11,
SB-12, SB-14, SB-140,
, SB-16, SB-17,
, SB-19, SB-20,
, SB-22, SB-22s,
, SB-24, SB-25,
, SB-27,
, SB-30,
, SB-80DX


Don't Just Read the Web Site, Get the Book!

The above information was excerpted from the in-depth information in Nikon Flash Guide. Besides flash specifications, you'll find a full set of operating instructions for each flash in the book. Plus, most cameras from the Nikon F3 forward are covered in the detailed section on interactions and capabilities in the back of the book. That's all in addition to the clearest description of how the Nikon flash system works that opens the book. Click on the cover in the right column to order your copy from amazon.com!



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