My new meter has a switch that says photons per square milimter, how does that work..... Les (hehe) -----Original Message----- >From: Roger Eichhorn <eichhorn@xxxxxx> >Sent: Feb 8, 2007 9:22 PM >To: List for Photo/Imaging Educators - Professionals - Students <photoforum@xxxxxxxxxxxxxxxxxxxxxx> >Subject: Re: Watt-seconds in flash > >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 >> >> >> >> >> >> Food fight? Enjoy some healthy debate >> in the Yahoo! Answers Food & Drink Q&A. >
