On Dec 25, 2009, at 10:13 AM, Jack Davis wrote:
Don't know if this answers it, but.. Pg 89 in the 540 manual
includes the following: "Flash duration (1/2 peak each)--
(M1/1)flash; Approx. 1/1200 sec. (TTL) Fastest duration time:
Approx. 1/20000 sec.".
Nope, that doesn't really help.
The problem I'm facing is the specsmanship involved in flashes, and
that there are at least three different "standards":
guide number
Watt Seconds
Effective Watt Seconds
BCPS (Beam Candle Power Seconds)
On top of that, I'm willing to bet that every manufacturer defines the
terms to their best advantage.
My white lightning 10,000 is
10,000 BCPS
guide number 220 at ISO 100
and IIRC
160 WS
Does the guide number 4x that of the AF540 mean that it is 4 times the
light, or 16 times the light?
Jack
--- On Fri, 12/25/09, Larry Colen <[email protected]> wrote:
From: Larry Colen <[email protected]>
Subject: How many watt-seconds is the AF-540?
To: "Pentax-Discuss Mail List" <[email protected]>
Date: Friday, December 25, 2009, 8:54 AM
I'm curious about the difference in
power between my on camera flashes and studio flashes. When
I look for specs on the AF540 I can find guide number, but I
can't find it in Watt Seconds. Anyone know where to find
this number?
--
Larry Colen [email protected]
sent from i4est
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