----- Original Message ----- From: "Paul Moortgat" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Friday, September 02, 2005 12:46 PM Subject: EOS Speedlite 550 <> 580
> Is the new Speedlite 580 flash so-much better that the 550? > I've the feeling that my 550 is not always constant. Some picture (in > the same situation) get more light than others. Could this be as a result of not letting the 550 recharge completely? As I understand it, the ETTL system uses a low power pre-flash (~1/20) which is assessed by the camera's metering. After that it's open loop, I assume, with no feedback for low capacitor voltage when the main flash is fired. (Old fashioned thyristor type flash guns might be better much of the time, providing they have sufficient power to cope with a wide range of situations.) Distance information feedback (ETTL II) could be a joke if modern lenses return similar numbers to what I see in my EXIF data for some of my older L lenses. Unless the 580 has changed its modus operandi I can't see why matters should change much. I'm writing from my experiences with several 550EXs used by an amateur, me, in slow changing "studio" type shots. Results have been consistent, with some variation due to (high) specular reflectivity of silky materials when I had the gun on top of the camera - bounced shots were OK. Wouldn't surprise me if I was in a fast moving "news" situation, that my faith in my flashguns would suffer! Many people recommend FEL. I've tried it and it works with quite good discrimination between light and dark objects, but it's quite a slow process, so perhaps not suited to photo-journalism. Malcolm Milton Keynes, UK http://www.megalith.freeserve.co.uk/oddimage.htm * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
