Originally posted by Digitalis no one is telling you you have to use the polariser at maximum effect for every single shot, the uneven polarization of the sky with lenses wider than 15mm* can in fact be favorable in certain situations. Using polarisers on lenses longer than 200mm is of questionable utility as the FOV is very narrow, and the technical need for shutter speeds to be high to eliminate subject blur/camera shake.
I agree, but its quite situation dependent.
Originally posted by Digitalis No filter can reduce the effect of turbulent air, and it depends on the nature of the haze - the substance that is causing it, as to where a polarizer will be effective in reducing it.
If you are pointing the camera strait up, you are right, but closer to the horizon the wobbling air -effect have a distinct layered structure, wobbling more in the vertical direction then the horizontal direction.
Haze are another phenomenon, usually caused by ozone in the air and are more visible the more air it passes. This haze are polarized as it is caused by the same phenomenon that causes blue sky, Rayleigh scattering. Think of it as amount of atmosphere between the camera and subject.
Originally posted by Digitalis Weak ND filters have their place, and you cannot simulate their effect in camera.
Well, you are right but there are usually a lot of headroom for adjusting exposure before we reach jpeg DR levels. Modern almost ISO-invariant FF and APS-C cameras have 4-5 stops (a 2-4 for Canon) before they reach jpeg linear DR levels. Usually one arent strictly limited to a certain aperture and DoF ether. You can usually adjust the aperture a stop or two before begins do affect the DoF too much. That adds another stop or two in adjustability without having a filter. The same goes for shutter speed. If you want longer shutter speeds, odds are high you want a more noticeable effect then 1 stop.
Taking that large headroom into account the weak ND filters are quite nitpicky in my opinion. I prefer coarser steps to really shift the exposure triangle and play noticeable away from what is within the headroom of play without a filter.