CPL Filter

[motox424]

What is it used for? I received one with my latest lens purchase.

Thanks

[TheRileyFactor]

Its a polarizing filter. Basically reduces reflections and glare, like Polarized sunglasses

[TheRileyFactor]

I see you just added the 24-70 2.8 to your sig, how are you liking that one? It could possibly be my next lens purchase (seems like I'm following your Sigma lens purchases, just got myself a 70-200 f2.

[motox424]

Originally Posted by TheRileyFactor

Its a polarizing filter. Basically reduces reflections and glare, like Polarized sunglasses

OK- great! I'll keep that then

Originally Posted by TheRileyFactor

I see you just added the 24-70 2.8 to your sig, how are you liking that one? It could possibly be my next lens purchase (seems like I'm following your Sigma lens purchases, just got myself a 70-200 f2.

I'll find out tonight, as I will be using it for basketball. I just got that lens this morning i did do some randonm test shots, and as far as the AF being on the noisy side, I like it!

[TheRileyFactor]

Good luck with the BBall shoot! I am going to start shooting some sports, we'll see if I do a little BBall! I've been thinking about that one b/c it has received some great reviews, and I can get it basically if I just sell my 24-85. I heard the AF is noisy, but still very fast (just sounds slow b/c of the noise), but I'm not a wedding photographer, so bring on the noise! haha!

[ThePhotoBinder]

I won't test out the filter on a BBall game unless the sun is out. Unless someone knows something I don't.

[TheRileyFactor]

Who knows, maybe he's in one of those arenas with Bright-As-The-Sun lights... kind of like a sports photographer's dream, eh?

I think he's talking about testing out the lens tonight at the game

[ThePhotoBinder]

oh, then testing always good.

[Pixart]

I have even used the polarizer shooting horses - yes horses. On a high/full sun day the fur can reflect a lot of light and the horse will have glaring burned out spots. Polarizer works nicely to eliminate those ugly reflections. Not to mention a pl adds nice pop to the sky.

[Ed Shapiro]

Y'all are forgettin' some important information regarding polarizing filters. First of all the "C" in "CPL" stands for "CIRCULAR". A circular polarizer can be used with auto-focus and auto-exposure cameras without interfering with those automatic functions. The LPL or LINEAR polarizer can be used with manual cameras of all types such as non-automatic film cameras and view cameras but are not compatible with most of today's DSLRs in that the all feature numerous automatic functions.

Polarizing filters have may usages in in landscape and commercial photography in the areas of reflection reduction or elimination. The most popular usage is darkening of the sky in outdoor photography. The filter will darken a CLEAR sky at 90 degrees to the sun without affecting gray tome or color rendition. The filter is rotated in its' mount until you see the effect you desire.

Polorizers do not eliminate reflections from highly polished metal objects such as small chrome plated electrical appliances or mirrors. When shooting such items tenting of the items with white seamless paper or shooting flat mirrors and oblique angles are the only ways to control or eliminate reflections.

Because polorizers modifiy or eliminates reflections on such objects as leaves and other foliage, thay will provide greater color saturation in landscape photography. This reduction in reflections also effects roofing materials and window glass. You can shoot store window displays without bothersome reflections.

In certain cases, however, you may wish to retain all or some of the reflections. When photographing still water for instance, you may wish to see certain objects reflecting off of the water's surface- too much polarization can make a lake look entirely black.

In portraiture or photography of animals, I oftentimes find that polarization kills some or all of the specular highlight which are needed to give the images the sparkle and brilliance they need to "pop of the page". I will use only minimal or no polarization on animals and I never use polarizing filters in portraiture.

In copying flat artwork I recommend "cross- polarization"- this is where polarizing screens are place over the lights, each a 45 degrees to the camera/subject axis, and placing a polarizer on the camera lens. This will cut through all the glare and deliver a very clear reproduction. Again, rotating the filter will determine the degree of polarization. If you want to capture the texture in painting that are done with pallet knives or bas-relief work, you may only need partial polarization.

Polarizing filters have neutral density- most of them will cost you 2 f/stops. Speaking of cost, good polarizing filters are not cheap. Oh- in black and white photography a polarizer in combination with a (#25) red filter will give you dramatic black skies.

I hope this helps. Ed

[spector426]

I really hate to sound like a smart ass,but I have to ask the question. How can someone spend all that money on the glass and not have a idea what a cpl filter is used for Must have money to burn.
Rich

[swampler]

Originally Posted by spector426

I really hate to sound like a smart ass...

Then Rich, why did you? I don't see what knowing different types of filters have to do with buying and using lenses. I could see your point if someone dropped the cash on a 400 f/2.8 (or other expensive lens) without knowing what he wanted to use the lens for.

[Ed Shapiro]

Some otherwise knowledgeable photographers never have no use for a polarizer- I've been a professional photographer all my life and I don't know everything- I learn something every day. Also- different filter manufacturers have different designations for their filters and if someone is in the market for a polarizer, it is good for them to know what to specifically ask for and what that items is capable of doing and what are its limitation its limitations.

Ed

When I answer questions on the forum, I might as well take the time to give comprehensive answers so that other folks, who are not as experienced can look on and learn something.

Ed

[oldugly]

I might as well take the time to give comprehensive answers so that other folks, who are not as experienced can look on and learn something.

And that is why we love you Ed.

[TheRileyFactor]

Originally Posted by Ed Shapiro

When I answer questions on the forum, I might as well take the time to give comprehensive answers so that other folks, who are not as experienced can look on and learn something.

Ed

I think thats the understatement of atleast the day, Ed! While you may not have the most posts on this board, I would wager that you have the most PAGES posted out of anybody on the camel! Your responses are always VERY informative, and have helped me out a lot!

[Tedski TX]

Doesn't the circular polarization obviate the need to rotate the filter to adjust the polarizing effect? If so, why do CPLs come in rotating mounts?

Ted

[TheRileyFactor]

Wish I could answer, but I have no idea and was kinda wondering that myself... I do know that when I put on my polarized sunglasses rotating the filter changes the tint, but never makes it black, while doing the same thing with 2 pairs of polarized sunglasses makes it black...

would be interested to know as well!

[blumesan]

Originally Posted by Tedski TX

Doesn't the circular polarization obviate the need to rotate the filter to adjust the polarizing effect? If so, why do CPLs come in rotating mounts?
Ted

You do need to rotate the filter of all polarizers to achieve the maximum effect of the polarization. However you will only see the change in your viewfinder (and on your image) if you are pointing approximately 90 degress from the angle of the suns rays.

[Ed Shapiro]

Nothing is that odvious to everyone on this forum. There are people with vast knowlege of photographic theory and practice, there are full time professionals and there are people who are just getting started. For people who have never used a polarizing filter or do not as yet own one, I thought I would mention the rotating mount and the method of utilizing the filter. This explanation also goes to the fact that the photographer can find various levels of polarizations as he or she rotates the filter. When the filter is at its maximum polarization position (relative to the angle of the light source) the image will not black out entirely. When you cross/polarize two polorizers you can achieve the black-out effect.

Polaroid sun glasses are set up to cut down or eliminate glare coming off the road when you are driving toward the sun and it (the sun) is at a an angle of incidence where it is reflected right into the driver's eyes. There are fixed linear polarizing lenses- if you rotate one lens in front of the other, at a certain point you will get total cross-polarization.

Ed

[Tedski TX]

Here is a link to a web page from American Polarizers, Inc. with an illustrated explanation of how a circular polarizer works:
Circular Polarizer | Polarizing Filters & Film

I see now why a CPL still has to be rotated for maximum effect. The front surface is linearly polarized, like a standard linear polarizing filter.