Neowin Forums > Filters - Circular or not?

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Mr Spoon

Jul 12 2008, 20:55

I got a new lens yesterday so I am looking at getting a polarizing filter for it as my other filter is a simple UV one which doesn't seem to do very much

I read this on Wiki:

Quote -

The difference is that a circular polarizer alters the light leaving the filter and entering the camera by using a quarter-wave plate to circularly polarize that light. This has the same effect photographically as a linear polarizer, reducing glare in the scene The metering and auto-focus sensors in certain cameras, including virtually all auto-focus SLRs, will not work properly with linear polarizers because the beam-splitters used to split off the light for focusing and metering are polarization-dependent. Circular polarizers work with all types of cameras, because mirrors and beam-splitters reflect both circular polarizations equally.[

Does that mean I should be looking at circular filter for my D60?

What gets me more is that there are three different types of the same one:

Hoya 52 PL-Cir - £9.39
Hoya 52mm Polarizing Filter - £11.95
Hoya 52mm PRO1 Digital Circular PL Filter - £21.95

Obviously quite a difference in prices. . .

MR_Candyman

Jul 12 2008, 22:11

yes, get a circular.

the Pro1 is a decent filter, but honestly, if you can, go for a better one like a lee or b&w

Mr Spoon

Jul 14 2008, 09:25

A B&W? But I want colour?

My question was what is the difference between the filters above?

Pandya

Jul 14 2008, 09:45

Between the first and second filters you listed, I can't see much if any difference. Could just be a pricing variation. The third filter however, is a higher quality circular polariser - and always get the best quality filters you can. No point putting bad glass in front of good glass

MR_Candyman

Jul 14 2008, 10:03

Linear polarizers (non-circular) affect the camera's autofucus system. AF sensors view the image through a semisilvered mirror, which results in partial polarisation of the light
reaching them. If the light coming through the lens is linearly polarised then how much of that light reaches the AF depends on the angle of polarisation and whether it matches that of the reflections en route to the AF sensors. That is why a CP must be used with AF cameras.

giga

Jul 14 2008, 13:26

Quote - (Mr Spoon @ Jul 14 2008, 05:25)

A B&W? But I want colour?

My question was what is the difference between the filters above?

B+W is a brand of a filter, not black and white.

http://www.schneideroptics.com/ecommerce/C...lay.aspx?CID=57

Get the Pro1 CPL if you don't want to go overboard on costs.

Mr Spoon

Jul 14 2008, 14:32

Hmm, now I do feel sheepish

Well, I want the best images I can get so I think I will stick with the best - I have a bit of money spare at the moment

giga

Jul 14 2008, 14:45

Mmmk: http://www.amazon.co.uk/Circular-Polarizer...6704&sr=8-1

£70

Mr Spoon

Jul 16 2008, 13:28

lol, oooh - that's a bit much!
I think i'll go for the £20 version.

Thanks giga - you really know your stuff

VazaGothic

Jul 16 2008, 15:19

Quote - (Mr Spoon @ Jul 16 2008, 06:28)

lol, oooh - that's a bit much!
I think i'll go for the £20 version.

Thanks giga - you really know your stuff

Don't forget to get the filter of the size of your lens filter thread (or a bigger one (eg, the 77mm) and get a step-down ring).

That way you should be able to use the same filter with different lenses as they may be using different filter threads (62mm, 77mm, etc). It's cheaper to get a step-down ring than to get new filter for new lens

Also, getting the bigger size of a filter should prevent possible problems with vignetting

MR_Candyman

Jul 17 2008, 05:43

Quote - (VazaGothic @ Jul 16 2008, 15:19)

Also, getting the bigger size of a filter should prevent possible problems with vignetting

it will also help if there's a problem with seeing the ring of the filter, as the step down ring isn't as thick

metro

Jul 19 2008, 06:58

Something else to consider. Sometimes it's a good idea to buy a larger diameter filter, such as a 77mm with step up rings for each lens to use it. That way you don't spend a lot of money for different filters for different diameter lenses.

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