Re: [ATM] Betr.: Re: cutting a big piece of plate glass - Polarizer

[Richard <cnc@cncservo.co.uk>]

Hi Dominic-Luc,

Friday, July 13, 2007, 6:14:10 PM, you wrote:

DLW> On Fri, 13 Jul 2007, Richard wrote:


DLW> I never found one that was purely 2 linear polarizers.

OK, having dredged the deeper darker brain cells, I recall circular
polarisers are used in photography, as are linear.

No, they are not two linear polarisers, they are just one linear
polariser or one circular polariser. The purpose is not to act as a
variable neutral density filter, it is to act as a filter to
selectively block out strongly polarised light, like sunlight
reflected off water for example. If the filter is marked PL it is
linear polarised and if it is marked PL-CIR it is circularly
polarised. Both have there uses, but I believe one is better for auto
focus and one is better for manual focus camera, and no, I can't
remember which. Never seen a pair in one cell though Dominic.

-- 

Best regards,
  Richard in the UK

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