Spinning the Polarising Filter

[futureal33]

I keep reading reviews that say "front rotating element, so bad for polarising filter users" and "will be a nightmare for CPL users" etc etc

Having just taken ownership of a Hoya CPL.... what is the disavantage to it rotating? I cant see the problem?

 

[TCR4x4]

Beacuse you set the position of the CPL to get the desired effect. If the front of the lens spins, it will move the CPL everytime you refocus and you'll have to reposition the CPL.

 

[TinaC]

If the front element of your lens rotates whilst focusing it means every small alteration in focus will need a corresponding alteration to the polarising filter - this may then disturb your focus so you will alter that and then you will need to adjust the filter...

oops, verbal diarrhoea made me too slow

 

[futureal33]

Is the CPL graduated? Mine just looks the same colour/tone all over?

 

[The Human Tripod]

If the front element of your lens rotates when you zoom or focus, it will turn the CPL with it, meaning you will have to rotate the CPL again to get the level of polarisation you want.
Of course you'll need to be carful when turning the CPL not to turn the front element or you'll knock the focus out, rinse and repeat.

CPLs are not graduated.
Find a reflection on glass and turn it to see the effect. Or wait for a sunny day (but you could be waiting a while )

 

[TinaC]

Is the CPL graduated? Mine just looks the same colour/tone all over?

Circular polarising filters have a rotating ring to enable you adjust to the current light conditions. The effect is against the whole image. Unadjusted it will probably darken your image a bit but you don't get the full effect.

 

[geoff-d]

It's more to do with zoom lenses - with some, the front of the lens rotates as you zoom in and out to change compsosition, which means having to re-rotate the polarizer each time - not a huge problem, too much fuss is made about it but just another thing to remember I guess, though it soon becomes habitual to tweak the polarizer each time lens is zoomed/focused

Geoff

 

[Martyn...]

Is the CPL graduated? Mine just looks the same colour/tone all over?

I was going to attempt a simple explanation but you are probably as well reading this LINK.

Basically you have two filters with lots of fine lines on them, not solid colour.

 

[futureal33]

I was going to attempt a simple explanation but you are probably as well reading this LINK.

Basically you have two filters with lots of fine lines on them, not solid colour.

A very good read Thank you

I will experiment later, I had no idea that you could adjust the amount of polarisation by rotating it, I thought that it was just loose! lol