Polarizers

[stamper]

It is a fact that a polarizer will reduce the metering by 2 stops so raising ISO to maintain a good shutter speed for hand holding maybe needed. What I am not sure about is the effect of auto ISO. Will it fight against the effect of the polarization or is it Ok to use?

[ptakeuchi]

stamper,

Using auto iso should just meter through the lens, taking into account your polarizer's light reduction, meaning that you'll be raising your iso value to ~2 stops above what you had without a polarizer. Generally speaking though, you're using a polarizer in bright light which means slower ISO, so the penalty is not that much, i.e. ISO 100 to 400. Or you sacrifice some aperture instead.

Paul

[Slobodan Blagojevic]

For what it is worth, there are modern polarizers that let more light through, so that the light loss is more in the range of 1-1.5 stops, rather than the classic 1.7-2 stops.