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- Path: sparky!uunet!think.com!rpi!bu.edu!bass.bu.edu!dtang
- From: dtang@bass.bu.edu (yunfei zhang)
- Newsgroups: rec.photo
- Subject: Re: rec.photo FAQ and answers
- Message-ID: <102096@bu.edu>
- Date: 16 Nov 92 04:20:34 GMT
- References: <1992Nov16.020913.29565@nmsu.edu>
- Sender: news@bu.edu
- Reply-To: dtang@bass.bu.edu
- Followup-To: rec.photo
- Organization: Boston University
- Lines: 23
-
- > Do I need a 'circular' polarizer, and what is one, anyway?
- >
- > Circular polarizers are just like regular polarizers, but
- > have an additional optical element to stir the light up
- > after the filter has done its thing. This stirring keeps
- > autofocus mechanisms and some light-metering mechanisms from
- > getting confused by polarised light. If the manual says you need
- > to use one, you likely do.
-
- The above is what I just read from the rec.photo FAQ. Frankly, I
- don't think it is well written. The only thing I learned from
- above is that a "regular" polarizer may confuse the auto-focus
- machanism, but I still do not understand why.
-
- I understand the differece between linearly polarized light and
- circularly polarized but I have a tough time to understand how
- the CP will do the same job as LP without fool the autofocus
- system.
-
- Anybody has a better explanation to satisfy my curiosity? (Thanks)
-
- DMT
-
-