Originally posted by clickclick
As in UV filters, polarizers share the same constraints. I'd stick with brands like B+W, the top Hoya series and so forth. On something like the 15, be sensitive to how much you dial in the filer and your angle to the light. You can get a severe gradient across the sky. That said, they still can be quite effective on wide angle when used properly. I would also recommend low profile. Thing is, on the DA15, if you get it in 49mm, you can still use the built in lens hood - it may be worth getting a couple different size CPLs for your most used lenses. The specific filter I know fits inside the hood (because I've used it) is the B+W XS-Pro Kaesemann High Transmission MRC-Nano Filter. I know you're hanging upside down relative to where I sit, but for reference, this one:
B+W 49mm XS-Pro Kaesemann High Transmission Circular 66-1081470
And yes, take off the UV. Stacking filters of any type if not necessary is to be avoided for all the reasons there's such a debate on filters to start with.

$50 is ok, not a ridiculous price to pay, and I take your point about different filter for different lenses as in the case with my DA15mm currently in that it does have a UV filter on it 'permanently' and when adding on a ND filter (tut tut) for a shot etc vignetting does occur, but I can usually work around it (ie the first non ND shot of the scene with quick exposure is fine, no vignetting, it's only the slow mo water stuff frame that has vignetting, and that means a crop at the bottom usually only (as water doesn't live in the sky often

)
Good to know that one fits on the DA15mm and allows for the hood to pass. I kinda want to see shots now with the DA15mm and a polarizer on, see if the 'bell' thing is happening or not etc.
What about ND filter and Polarizers then? Which order of putting them on is right? I ask this as I live in the Blue Mountains, plenty of bright aussie blue skies and water falls, I already use ND filters, I have 2, one is not that dark, the other very dark (which I seldom use), I know the polarizer darkens things somewhat so I'm thinking it may assist in getting that extra second in some shots with the lighter ND filter which doesn't (on some bright days) manage to extend the exposure much, but this also giving way to helping to control the overall exposure of the image by way of the polarizing benefits (ie it takes care of the sky and clouds).
Originally posted by ramseybuckeye
They are like everything else, some are better than others. To get a decent polarizer you don't have to spend a fortune, but beware of the really cheap ones. I would stick with a reputable source, because I think there may be counterfeits out there. A bad filter can blur your photos, it is an extra piece of glass. However your 52 mm filter is not going to work for your DA 15, you won't be able to use the hood with a step up ring. There are slim polarizers too that will work better with certain lenses that can tend to vignette.
Yep thanks for that.
Originally posted by Digitalis
Considering how the lens hood protrudes from the DA15 when collapsed, I doubt even a step up ring will be able to clear it. You might have to put a blank filter between it and the step up ring, however doing so might cause issues with vignetting.
When using GND filters for use with wide lenses you WILL have to invest in a square filter system - which isn't exactly a cheap venture
Yeh nah it doesn't, with the DA15mm it has to be the filter only really and nothing else to avoid vignette.
Ok you lost me at the last part a bit GND is gradual neutral density filter, similar to a polarizer I guess? But if wanting to use that on a 15-24mm then yer suggesting those large square filter thingies are a better option (but more expensive)? Honestly I think I'm looking towards the future, I just want to make a right purchasing decision (which may involve putting off on buying any filter for now and saving funds if that means big square thingies).
I get that polarizers are used for different things, such as taking a pic of a car, a stream, a waterfall (and no sky), but then also just mega wide landscape sky ones too. Perhaps I get a 49mm polarizer for use on the FA50 and DFA 100, for those stream and car shots etc, and then work towards a different system for wider lenses down the road?