OK guys...
Well perhaps I have it wrong...
Correct my arithmetic:
1 joule per second is a watt.
1 watt second is 1 joule per second for 1 second
500 watt seconds is 500 joules per second for 1 second
(or in the case of a theoretical flash unit, its 500 000 joules for 1/1000th of a second)
A 500 watt lamp, burning for one second is 500 joules too so a 1-second exposure should give the same amount of energy (light) to the sensor/film as a single burst from a 500 ws flash.... 500 joules????
Where did I go wrong?
My point was:
In a perfect world, a single burst on a 500 WS flash unit should require the same aperture as a 500W tungstren light at 1 second exposure which is also 500 WS.
(Not allowing for the inefficiency of the tungsten lamp)
A good part of the energy is given out as heat in both systems so it becomes impossible to actually relate watt-seconds to light output.
Head of the Department of Photography,
Muscat
Sultanate of Oman
From: Qkano <wildimages@xxxxxxxxxxx>
To: List for Photo/Imaging Educators - Professionals - Students <photoforum@xxxxxxxxxxxxxxxxxxxxxx>
Sent: Friday, February 9, 2007 2:58:09 PM
Subject: Re: Watt-seconds in flash
>
>>No! Watt-seconds is just that. Watts times seconds. It's a measure
>
>That's exactly what I said... allow me to do the math for you:
Hershell
I thought you had it wrong too I'm afraid.
I understood the correction watts.seconds was much clearer.
Bob
___________________________________________________________
Tiscali Broadband from 14.99 with free setup!
http://www.tiscali.co.uk/products/broadband/
Finding fabulous fares is fun.
Let Yahoo! FareChase search your favorite travel sites to find flight and hotel bargains.
