Cir-polarized filter as a protective filter

I have used uv filters as protection for some time now. I have been thinking about using a cir-polarizer as an everyday protector, I haven't used a polarizing filter yet, would ther be any negatives to doing this?

Thanks, Dave

Depending on the polarizer you're using you'll loose 1-2 stops of light with a CPL.

Negatives are, you lose a stop or more of light. The effect of a polarizer is inconsistent unless adjusted for each shot. Its a bad idea for several reason, namely you dont need a protective filter to begin with unless you are getting sea spray or blowing sand. A filter of sufficient quality costs as much or more than a new front element.

As has been mentioned, the loss of light can be an issue, particularly when using a slow lens on a dull day and needing fast shutter speeds. The light loss will also translate into having a darker viewfinder image which may be a problem at times.

In addition, where protective filters are designed not to affect the image (although they can negatively impact the image, that is unintentional) polarisers are intended to have an effect, and it can be quite a significant one. Where this effect is wanted that is great, that is why you fit a CPL normally, to affect the image, however there are times it may negatively impact your shots if you are leaving the filter on all the time. With a wide angle lens you may get patchy blue skies, blue at one side and fading away at the other, you may find stress patterns appearing in windows (multicoloured rainbow patches like oil on water), you may be removing reflections that you wish to keep etc., etc.

I am a big fan of polariser filters, I have 4 in different sizes. I use them quite often when they will benefit my image, however they are not used most of the time. I would estimate I use them for about 10% of shots I take, if that, the rest of the time the lens is bare as there would be more negatives to having them on than benefit.

In theory, yes they can be used all the time, but why live with the light loss and other downsides when they add nothing to the result?

Awesome thank you, i wont be using it as primary protection then. I do agree that filters may reduce the quality of photos, however my skill level isn't at that point where a uv filter is going to affect my photos to the point where I would risk scratching my lens

Your lens is harder than the filter, its just not a significant risk. If youncan activate a shutter button you are at the stage where a protective filter can harm your photos. Use a hood for protection.

As long as you use good quality modern UV filters, you won't see any negative impact on your photos. I wouldn't use a CPL as protection for the reasons already mentioned by others. I use B+W MRC UV filters on my lenses and I'm about to try a new brand from kickstarter, Breakthrough Photography.

gonzogolf wrote in post #17379256
Negatives are, you lose a stop or more of light. The effect of a polarizer is inconsistent unless adjusted for each shot. Its a bad idea for several reason, namely you dont need a protective filter to begin with unless you are getting sea spray or blowing sand.

This. Plus, CPL's can negatively affect skin tones. If you insist on a protective filter (UV or clear) spend the money for a decent one.

I have a brother-in-law who bought a new camera, and used a cheap CPL as a protective filter because someone told him it was a good idea. It was on 24/7 instead of a lens cap Indoor, outdoor, day and night, and he didn't even know enough to turn it for the best effect. He couldn't figure out why his pictures came out like crap. He's a know-it-all douche, so I didn't bother trying to clue him in. He later said he was going to sell the camera to his son, which might give you an idea of what he was like. (This camera sucks, I'll sell it to my boy)

Anyway, just don't do it

How about he using the filter as protective when he doesn't shoot, and when he start to shoot he take off the filter? say he put the filter only when he walk around and want to keep the lens protected from outer conditions, i can use a UV filter and i take it off if it affects my photos quality, so any filter can do the same job for protecting without shooting then, but honestly speaking, i never use UV filter when shooting and rather i use different filters such as ND or CPL for different applications, but never UV.

Tareq wrote in post #17380019
How about he using the filter as protective when he doesn't shoot, and when he start to shoot he take off the filter? say he put the filter only when he walk around and want to keep the lens protected from outer conditions, i can use a UV filter and i take it off if it affects my photos quality, so any filter can do the same job for protecting without shooting then, but honestly speaking, i never use UV filter when shooting and rather i use different filters such as ND or CPL for different applications, but never UV.

Isn't that what the lens cap is for?

Davevw3 wrote in post #17379461
where I would risk scratching my lens

I'm intrigued as to what you believe may scratch your lens. Glass is very, very hard. The only things in your house (barring an interesting mineral collection) that are likely to be able to scratch glass are - diamonds, specially hardened steel, quartz and other glass. You're most likely to encounter quartz in the form of sand, and it's in this form that it can damage your lens. But only if you grind the sand into the lens - proper cleaning is required. Glass can also scratch glass. Glass in the form of fine, sharp, shards is particularly dangerous. The sort of fine, sharp, shards one might get when a 'protective' filter shatters.

Ironically, the only two places where I shoot that may be considered environmentally unsafe for a front lens element are places where I use a CPL filter anyway. I find a CPL useful at the beach during daylight hours to enhance colors and cut down reflections, and also to cut down reflections on the water in the geothermal areas of Yellowstone, where some of the gases coming off the features may be corrosive towards lens coating and the glass.

On our last trip to Yellowstone, I packed a UV filter for the geothermal features, but ended up using a CPL in those areas all the time. We will be visiting the park again this year, and I will not even bring along a UV filter.

Filters for effects, lens hood for protection.

Tareq wrote in post #17380019
How about he using the filter as protective when he doesn't shoot, and when he start to shoot he take off the filter? say he put the filter only when he walk around and want to keep the lens protected from outer conditions, i can use a UV filter and i take it off if it affects my photos quality, so any filter can do the same job for protecting without shooting then, but honestly speaking, i never use UV filter when shooting and rather i use different filters such as ND or CPL for different applications, but never UV.

A properly designed LENS CAP would do the job you're describing and at much less cost. The lens cap also wouldn't have a tendency to shatter if it's bumped against something. Almost all filters used for "protection" are very fragile and can be easily shattered.

Well it looks like "Protective Filters Not Required" win this round...

That makes sense, I'm worried about any dirt, sand, particles, greasy fingers and anything else from getting on it. I have stretched my budget to acquire my baby lol.