Polarizing or cicular polarizing?

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Barnesy

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Hi. Just wondering the difference between a polarizing filter and a circular polarizing filter.

Just went to buy one and Hoya offer both types in 58mm.

Im confused lol. Which one do I need?
 
One is probably linear. You want a circular. This means you can rotate it and adjust it to your liking.
 
if I understand correctly
something about digital sensors, half-silvered mirrors and auto-focus
all combine to mean DSLR needs the circular persuasion
:thinking:
 
Shak said:
One is probably linear. You want a circular. This means you can rotate it and adjust it to your liking.
Click to expand...


You need a circular polariser so that the autofocus will work.

But linear / circular is all about the way the polarizing coatings work on the filter, nothing to do with the shape of the filter frame or its ability to rotate.

You can get both linear & circular polarisers in different mounting types.
- screw on round filters
- round filters that slot into rectangular filter frames, these round polarising filters fit in a specal slot (closest to the lens on my cokin holder), and projects out the side of the holder like a thumbwheel so it can be rotated inside the holder and independant of other filters that may be in use (eg. ND Grad).
( - I have never seen them but guess its possible to have a rectangular polarising filter in a rectangular frame, as you can rotate the frames)

the advantage of the cokin holders is you only have to buy cheap adapter rings, not filters, if you want to use them on a different sized lens thread. Get the P type, slightly bigger than the A type and so less risk of vignetting (black corners) on wide angle.
 
Cool, thanks everyone.

So let's see if i've got this right.

A Cokin holder is an additional piece of kit which I should invest in that fits on the end of my camera allowing me to rotate a filter? Where do I buy one?

If I just order this Hoya 58mm circular polarizer I assume that just fits on the end of my lens?

Sorry, im new to this.:bonk:
 
The Hoya filter will fit straight on and is already rotating.
 
Thanks for asking about this Barnesy as Im also looking into them.:thumbs:
 
Also can anyone reccomend the cheapest place to buy them? (cokin P series)
 
Both linear and circular polarisers can be rotated to adjust the polarising effect. I think a linear gives a stronger effect, but the way the coating is applied causes AF or metering problems on dSLRs, which is why circ. polarisers are more common these days.
 
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