No! Watt-seconds is just that. Watts times seconds. It's a measure
of the amount of energy released. A watt is a rate -- energy per
second. Multiply that for the duration in seconds to get the total
energy release. For example, you buy electricity by the Kilowatt-
hour. But perhaps you mis-spoke. The rest of your commentary seems
to be correct.
Roger
On Feb 8, 2007, at 11:07 PM, Herschel Mair wrote:
Hi Lea,
The WS (or Joules) specification used in studio flashes is a little
misleading.
It's really a measure of electricity and not light. One
manufacturer's 500WS light may put out much more or less light
than another's.
It's useful for comparing lights in a single manufacturer though
and you can be pretty sure that the Elinchrom 400WS light will give
you twice the light output of the Elinchrom 200WS.
What you really need is the guide number (GN) with the umbrella or
light shaper you will be using.
When thinking of watt-seconds, think of "WATTS PER SECOND"
A 500W tungsten lamp will give you, let's say, f/11 at 1 second
exposure. (500 WS)
A 250W tungsten light should give you f/8 at 1 second under the
same circumstances (250WS)
etc.,
Herschel Mair
Head of the Department of Photography,
Higher College of Technology
Muscat
Sultanate of Oman
Adobe Certified instructor
+ (986) 99899 673
www.herschelmair.com
----- Original Message ----
From: lea murphy <lea@xxxxxxxxxxxxxxxxx>
To: List for Photo/Imaging Educators - Professionals - Students
<photoforum@xxxxxxxxxxxxxxxxxxxxxx>
Sent: Friday, February 9, 2007 4:06:00 AM
Subject: Re: Elinchrom Studio Set
I'd buy it in a hearbeat. Elinchrom is some of the best lighting
you can buy.
The heads are the lights themselves and 250 and 400 is the watts
per second the lights can output. There's all sorts of technical
stuff to explain it (and hopefully someone will) but one way to
think of it is that it is like a guide number for your studio
lights. Basically, the higher the number the more power and the
faster recycling time.
This will be more than sufficient for studio work though you may,
in time, wish to add a third light and softboxes instead of umbrellas.
Good for you and good luck.
Lea
On Feb 8, 2007, at 5:37 PM, Elson T. Elizaga wrote:
I'm planning to buy this set:
http://www.ebay.ph/viItem?ItemId=150089965064
What is 250 and 400 in the phrase "2 heads: 1x250 and 1x400"?
Watts? What do you think of the whole set in general? Is it
sufficient for portraits? Food and jewelry photography?
I'm not a studio photographer so some things in this area are
still baffling to me.
I've asked the seller already, but I'd like to get your opinion, too.
Elson
lea murphy
www.leamurphy.com
www.whinydogpress.com
blog: web.mac.com/leamurphy
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