[PPPPPP42]

What theunartist was getting at there is that on some lens (like several of my old A series) the end of the lens where the filter is held rotates as you turn the focus ring, this totally messes up a CPL as you would have to rotate it again after every change. ND filters and UV filters don't care how they are rotated.

EDIT: also I would also use a ND filter often for getting a shallower depth of field on bright sunny days.
That is to say ND filter allows me to open the aperture up wider than would normally work for correct exposure so that I could get a much thinner depth of field (less area front to back in focus). This is handy if I want to blur the background of a portrait or something, especially on my A50 1.4.
Also given the choice, if the prices are similar shop the board sponsors since they stock a ton of these and usually don't stock the cheap crap, plus you help pay for the forums too.

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Last edited by PPPPPP42; 04-03-2012 at 08:30 AM.

[dms]

Outdoors during the day manual focusing with or w/o a PL filter will be no different. As for linear vs circular (as I said before) I suggest linear. Partly it is a question of what you want to spend.

I happen to use linear--but except for PL with indoor's copying of paintings I almost never use any filter (with digital), and when I do the only issue I would be concerned with is more flare, but that's not about linear vs circular, rather it's about multi-coating, which is too costly to justify (IMO) in a PL as it means 3 glass surfaces to coat.