Light becomes polarised when reflected off non-metallic surfaces, and the effect is maximised at certain angles. The mirrors inside an EOS camera are set at close to these angles so if incoming light is linearly polarised you will get poor AF and possibly poor exposure metering (as in Canon FTb & F1). A circular polariser consists of a linear polariser (which suppresses the external reflections) followed by a quarter-wave plate which scrambles the exiting light back into random polarisation, allowing your camera to work correctly, i.e. AF & exposure metering. [Circular polarisers only work correctly when used as designed - they are not reversible.]
M Stewart Milton Keynes, UK ----- Original Message ----- From: <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, March 12, 2002 6:54 AM Subject: EOS Polarizer > > Hi all, > > I'm the owner of an EOS300 (Rebel 2000) + EF 28-105 3.5-4.5 USM lens. I want to buy a polarizer > but I have some doubts. Why is better a circular polarizer that a lineal one? Are there differences > in the resulting image? Is it worth to buy an "expensive" one? > > Having asked in an store they have three models(sorry but I don't remember the branches). The > prizes were: 18 Euros (16$), 30 Euros(27$) and 60 Euros (55$) snip * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
