Hoya hd/cpl filter

Hi team,

I just purchased a Hoya hd/cpl filter for my 15-85mm IS USM.

Should I leave this on the lens at all times???

I wouldn't keep it on all the time. You'll lose light due to the CPL (up to 2 stops), and that can be trouble when shooting in low light situations. And you can sometimes get an uneven polarizing effect at wide angles (15-18ish) on your EF-S 15-85. It can be a pain to keep changing out filters, but it's worth it.

Outdoors in the sun, yes.
Indoors it doesn't do much at all (although it can cut reflections off a window).
At night you'll be losing too much light (but then, you can enhance/remove light-reflections off the water, and you'll probably want the light-loss to make longer exposures to blur the water).
And when it's cloudy, it depends on how lazy i'm feeling, it doesn't do much either way.

Thanks mate.

I'll leave it on during the day and take it off at night!!! Easy!