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Anyone noticed the SEF 220A flash?

Started Apr 22, 2012 | Discussions thread
nx200USER1 Senior Member • Posts: 1,097
Re: Anyone noticed the SEF 220A flash?

shademaster wrote:

GN usually means the distance for proper exposure at ISO=100 f/1. Shutter speed doesn't matter for the exposure (if you exclude ambient light sources). So for typical aperture, e.g. f/4 (one sixteenth the intensity of f/1), the SEF8 will get you proper exposure at 8m@ISO=1600, 4m@ISO=400, or 2m@ISO=100. For SEF20, it would be 20m@ISO1600, 10m@ISO400 and 5m@ISO100. This is all assuming there are no reflecting surfaces (ceilings/walls)... reflecting surfaces would help a bit in terms of capturing light that would otherwise be lost.

Calculation is trickier for SEF220 since it has a zoom motor that changes the solid angle over which the light is distributed, but it's a bit weaker in terms of energy than SEF20 despite the higher number (the "22" number refers to a guide number at a longer zoom setting on the SEF20). I almost always bounce my SEF20 and YN-560 off the ceiling, so all these calculations get tricky, and it's a lot more look billiards as opposed to T-Ball to dial in the right aperture, ISO, and flash intensity.

For what I do, I don't think there would be a compelling reason to take the SEF220 over the SEF20. It has a manual setting, but I have a manual flash (and the SEF20 will fire manually off-camera at full power for use as a 2nd strobe). Hope this helps.

That was very helpfull, thanks very much. Your example above breaks it down and was easier to digest than some of the online course related material for flash photography.

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