EOS Re: Flash sync speed - how important is it? [OT?]

[Henry Posner/B&H Photo-Video]

At 04:05 PM 08/06/2001, you wrote:
>Could this be true?
>Is Nikon FP better than the Canon HS E-TTL?

I wasn't sure of the answer, so i copied the whole thread to my friend Thom 
Hogan, author of The Nikon Field Guide. His reply:

<<<
Henry:

The poster at www.chemlhelsinki.fi must be a Canon user. The statement
"therefore a part of the flash energy is wasted" doesn't apply to the Nikon
FP mode. (Caveat: I have no familiarity with the Canon system, so I'm merely
interpreting using my knowledge of Nikon systems.) Which brings me to:

Yes, the Nikon FP mode is a manual flash mode, and to use it effectively you
sometimes have to iterate settings (on my flash instruction cards I note in
Step 6 "you may find that you have to go back to Step 4 and iterate until
all the settings match up." The first payback is that the entire power of
the flash is released across the full set of pulses during the shutter
cycle, maximizing GN. The second payback is that you have control over the
frequency and number of flashes during the cycle. Really careful
photographers shooting certain kinds of motion sequences can use this to do
interesting things, such as calculate the actual speed of an object in a
scene (imagine someone doing golf swing analysis, for instance--by starting
the shot at the top of the swing they could probably calculate club head
acceleration and impact speed--of course, these days they do that kind of
analysis with video, but if you need the resolution, the Nikon FP mode is
pretty useful).

In general, FP flash modes aren't very useful for regular shooting, as the
lowered GN means you can't use it at very long distances (at 1/4000 second
at f/2 we're talking about a maximum of 10 feet for 85mm lens, half that for
a 20mm). And with a shutter speed that short, the ambient lighting better be
darn bright, or else anything not lit by the flash is going to be black.
This tends to restrict motion to a parallel plane to the camera, which again
limits usefulness. Still, it can produce some pretty interesting results
when used correctly (hmmm, I think I'll go to the Velodrome on Friday night
and "play").

The flash book, by the way, is supposedly at the printer (of course the
printer is in Belgium, and Belgium is on holiday in August). Silver Pixel is
now predicting September, but given their problems lately, I don't know
whether to believe them or not. I'd still love to come in and do a
talk/signing, but I think we should probably not schedule anything before
end of September to play it safe. By then, my self-published D1, Coolpix
995, N65, and N80 books may even be available, too.

Thom Hogan, writer/photographer
author, Nikon Field Guide, Nikon Flash Guide, Nikon Coolpix Guide
www.bythom.com
 >>>
--
regards,
Henry Posner
Director of Sales and Training
B&H Photo-Video, and Pro-Audio Inc.
http://www.bhphotovideo.com

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