Polarising filter and UV filter?

Is it a good idea to have a UV AND Polarising filter left on my 18-70mm lens at all times?

Thanks

Brian

meddyliol said:

Is it a good idea to have a UV AND Polarising filter left on my 18-70mm lens at all times?

Thanks

Brian

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Why? I use my polarising filter when I need it. And never use a UV filter as have never needed one.

Polarising filter will block some light getting to your sensor, so you'll end up using slower shutter speed or higher ISO. Like Scott says use it when you need it. I have one but haven't used it much yet, i'll use it for landscapes and not much else most likely.

It's just that I read somewhere that some people leave the polarising filter on all the time as well as or instead of a UV filter. I only use the UV filter as lens protection.

There are debates going on regarding UV filters as lens protection and I am not getting into that. All I know is that a UV filter adds another lens for image quality to be degraded and even though I do not really look after my lenses none of them have been scratched due to mis-use. Up to you if you believe in the lens protection theory. Never needed one in all my years of shooting and never will need one.

I shoot with a CPL outdoors all the time. Do I *need* one? No, but neither do I *need* all that reflective light that hampers my image, of which there is a lot; more than most people realize (see this video regarding CPL's). If you want something for protective purposes the CPL does that just fine, in my opinion, or you can switch to something like the Hoya HD Protector. I like the Hoya HD line of filters because the glass is very, very strong and the filters themselves are excellent.

If I did all my shooting in a studio I wouldn't bother with a CPL, but that's now how I shoot. The CPL protects my lens not so much from impact damage as from things like salt spray and sand (desert sand out here in Cali can be as fine as talcum powder) because I shoot at beaches and in the desert frequently. Shooting in such locations the CPL also works like a very light ND filter allowing me to use wider apertures for shallower depth of field.

There's all sorts of stuff that can happen to a lens besides impact damage... Stuff I'd rather clean off a $100 filter than I would a $1,000 lens. The filter I can clean with running water out of the kitchen faucet, the lens is another matter. What filter you use, and if you use one at all, should be based on your shooting and what you think is prudent under those conditions.
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Scott Murray said:

There are debates going on regarding UV filters as lens protection and I am not getting into that. All I know is that a UV filter adds another lens for image quality to be degraded and even though I do not really look after my lenses none of them have been scratched due to mis-use. Up to you if you believe in the lens protection theory. Never needed one in all my years of shooting and never will need one.

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I have a scratch on my 35mm. I don't even know how it got there. Sh*t happens but I got filters on my expensive lenses now since sh*t better not happen there.

Btw, stacking filters can lead to serious vignetting, especially on wider focal lengths.

Thanks very much for your inputs. Much food for thought. The answer is, there is no answer.

meddyliol said:

Thanks very much for your inputs. Much food for thought. The answer is, there is no answer.

Click to expand...

For stacking an UV + CPL there is a definitive answer; it's not needed and can at worst only have negative consequences. The UV does nothing but protect the lens which a CPL also does when you put it in front of the lens. So if you use the CPL, remove the UV.

There is no definite answer to the matter of protection or not; we all have to make up our own mind. I never did see the need for protection until I got more expensive lenses and my 35mm got scratched. If I'd rank all my lenses according to use, the 35mm is somewhere at the bottom so it is ironic she got damaged. I never dropped it nor bumped it and generally take better care of my lenses than my women and yet, it happened. It's just bad luck but when the price of your lenses goes up, ruling out bad luck pays more and more. It doesn't make sense to put a 100$ filter on a 100$ lens but if the lens costs 1k or more, it's a small percentage.

Unless you buy a 5$ UV from Lu Bish in China, it won't affect IQ negatively.

meddyliol said:

Thanks very much for your inputs. Much food for thought. The answer is, there is no answer.

Click to expand...

The answer is there's no single answer that's always correct.

Filters are tools; sometimes you need a tool, sometimes you don't but regardless there is no single tool right for every job.
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