[biz-engineer]

Now having the DFA24-70, all of the filters I used with APSC lenses are two small (I have a complete set of CPL, ND grad and ND filters for 67mm + ring adapters from 49 to 72mm).
So, I need a new set to fit the 82mm diameter of the DFA24-70, so I'd go for a filter kit such as the Cokin Z pro. I could get a 82mm circular polar filter but I saw that polar filters also exist as square version. The advantage of using square filters is that it's more versatile (I don't have to change filters for using lenses having a different filter thread diameter). Kind of stupid question, but I suppose the polarization is fixed, just wondering is this is correct and want to get confirmation of what this practically imply in terms of effectiveness as I've never used a square polar filter. Anyone using square polar filter as opposed to circular? Thanks.

[Adam Burke]

Check out the Nisi filter system. I think it might meet all of your requirements.

http://nisifilters.com.au/product/nisi-100mm-aluminium-filter-holder-kit-v5/

[max_pyne]

i got the NISI its very well made (got the kit with holder, Polarizer, ND 10 Stops and ND gradient) got some additional adapters 49-82, 58-82 & 62-82 to cover most of my lenses :-)
It is expensive.... and i think it's only worth it if you want to use special ND filters (reverse, hard, gradient)
but its big piece (a lot of small pieces sums up) of gear to take with...
The polarizer comming in the kit is a circular one that can be rotated with a special thumbscrew on the square filter holder

[MikePerham]

The problem with a square polarizer is that when using in combination with a ND grad, when you rotate the polarizer to where you want it the ND grad is not where you want it. Lee make a circular circular polarizer that can be turned independent of the other filters in the stack. Expensive but the best.

[TomTom]

I've not used his products yet but someone on PF mentioned him and I've been thinking I might try his stuff because the prices are nice.

The Filter Dude on ebay.