BeBu Lamar Posted November 27, 2020 Share Posted November 27, 2020 I am surprised that with my10ft ceiling and if I do a bounce at f/5.6 I have to have ISO at least 500 in order to have sufficient exposure. My other shoe mount flashes generally can do that at ISO 100 or 200. Link to comment Share on other sites More sharing options...
rodeo_joe1 Posted November 28, 2020 Share Posted November 28, 2020 Like nearly every other top-of-the-range Nikon speedlight, the SB-800 has a true and measured Guide number of around 28 (metres) at 100 ISO and 50mm 'zoom' setting. That gets you about a 4m round-trip bounce at 100 ISO and f/5.6, allowing a one stop loss for the reflection. What other flashes are you comparing it to? Because the SB-900 and 910 are no more powerful. And neither were the SB-800's predecessors, right back to the SB-24. They all put out roughly the same amount of light. Maybe your sample is failing? Tubes wear out, capacitors go leaky, circuits fail, etc, etc. Link to comment Share on other sites More sharing options...
conrad_hoffman Posted November 28, 2020 Share Posted November 28, 2020 It's annoying. Modern smart flash units are so expensive, yet not all that powerful. I had an ancient Vivitar that was quite compact yet had a guide number of 56. Or maybe it's my rose colored glasses. Link to comment Share on other sites More sharing options...
BeBu Lamar Posted November 30, 2020 Author Share Posted November 30, 2020 Like nearly every other top-of-the-range Nikon speedlight, the SB-800 has a true and measured Guide number of around 28 (metres) at 100 ISO and 50mm 'zoom' setting. That gets you about a 4m round-trip bounce at 100 ISO and f/5.6, allowing a one stop loss for the reflection. What other flashes are you comparing it to? Because the SB-900 and 910 are no more powerful. And neither were the SB-800's predecessors, right back to the SB-24. They all put out roughly the same amount of light. Maybe your sample is failing? Tubes wear out, capacitors go leaky, circuits fail, etc, etc. I guess my memory failed me. I tested 4 flashes the Nikon SB-800, Minolta X-320, Vivitar 383 and Sunpak PZ5000. Setting all of them at full power manual, flash aim straight up at the ceiling and the flash meter with the dome pointing straight up. At ISO 100, Shutter speed 1/60 the SB-800 register f/4 and 2/10. The Minolta f/2.8 and 8/10. The Vivitar f/2.8 and 7/10 and the Sunpak f/2.8 and 8/10. so the SB-800 is the most powerful in the group. By the way all of the flashes are set for 35mm coverage. 1 Link to comment Share on other sites More sharing options...
rodeo_joe1 Posted December 1, 2020 Share Posted December 1, 2020 At ISO 100, Shutter speed 1/60 the SB-800 register f/4 and 2/10. The Minolta f/2.8 and 8/10. The Vivitar f/2.8 and 7/10 and the Sunpak f/2.8 and 8/10. So about half-a-stop more powerful than 'other brands'. Sounds about right. Nikon and Canon's top-line speedlights have been fitted with 1400uF capacitors for years, while the likes of Vivitar used only a 1000uF or smaller cappy. However, nearly every 'good' cheap Chinese made flash uses a 1400uF capacitor these days. Link to comment Share on other sites More sharing options...
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