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  #1  
Old 07-19-2007, 03:29 PM
dlevy23 dlevy23 is offline
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Default Circular polarizer

Hello, I have a Canon Rebel Xti with the standard lens 18-55. I was wondering if somebody can tell me wich CL filter should I buy.
Thanks a lot.

Daniel
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  #2  
Old 07-19-2007, 06:44 PM
dlevy23 dlevy23 is offline
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Default Re: Circular polarizer

Why was this post locked and moved?
Thanks.
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  #3  
Old 07-19-2007, 11:33 PM
R-Coop R-Coop is offline
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Default Re: Circular polarizer

It was just moved to the correct section...

As far as filters go it all depends on you budget, I have 2 B&W CP filters & love them but they are on the pricey side. Here are a few things to look for, good glass will have a threaded ring holding the glass in, cheap ones use a spring loaded clip. I also stayed away from the slimmer models, the wide ones are easier to hold onto and turn. Hope this helps.
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  #4  
Old 07-20-2007, 01:20 AM
ronners ronners is offline
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Default Re: Circular polarizer

To figure out which filter you need for that lens you need to check the filter size (it's usually marked somewhere on the lens (my Nikon lenses are 77mm and 55mm). If you haven't yet embarked on buying filters and are planning to buy a few lenses, try to get the largest filter that will cover all your lenses - again, in my case I have 77mm filters as they work for my largest diameter lens, and via adapter rings can be used with smaller diameter lenses. The downside is that larger filters are more expensive. However, a small additional expense on a larger filter is better than having a filter that's too small for your new larger lens, and having to buy yet another filter.

As for filter types, yes, thinner is better. Go for better brands like B&W, Hoya, Heliopan etc. If you see a circular polarizer for $5 you'll unfortunately get what you pay for. Expect to pay between $25-$50 for something with good optical qualities. Beyond that price range differences in optical quality will most likely not be signficant.

Ron.
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  #5  
Old 07-20-2007, 09:29 AM
donluicu donluicu is offline
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Default Re: Circular polarizer

i recommend you Hoya filter.
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  #6  
Old 07-20-2007, 09:49 AM
PixelTerror PixelTerror is offline
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Default Re: Circular polarizer

In my view B+W polarize a bit too strongly, I think Hoya are more neutral. If you have several lenses buy a pola fitting on the largest one and adapter rings to screw it on others.
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  #7  
Old 07-20-2007, 03:35 PM
dlevy23 dlevy23 is offline
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Default Re: Another question

Do I keep the CL filter even if I'm doing indoor photos, would it stop light from coming in, or the filter is only good for outdoor photos?
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  #8  
Old 07-20-2007, 04:53 PM
Davidh34 Davidh34 is offline
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Default Re: Another question

Polorizers are just for outdoor photography, mostly for bright conditions, and for taking the glare off of shots of water or snow. have a quick search on thw web, though some of the better and more technical photographers on TE might answer you better. Here's some info I googled.

Polarizing filters are used for reducing reflections in photos and boosting contrast. They work by letting you selectively filter out light thatís polarized along certain axes. The end result is you can enhance blue skies and blue oceans/lakes - darkening them - and cut back reflections off non-metallic surfaces such as glass and water.

A polarizer is typically made from a thin sheet of plastic polarizing material laminated between two circles of clear glass. The filter is mounted in a separate rotating ring, so you can turn it to adjust the strength of the polarizing effect independently of the lens position. (the filter blocks incoming polarized light at certain angles, so adjusting the angle of the filter determines how much polarized light which may illuminate your scene makes it through the lens) Polarizers are thus thicker than normal filters, and increase the risk of vignetting (darkening of the corners) caused by blocking the light which enters the lens.

There are two types of polarizing filter. Standard linear polarizers work only with older manual-focus cameras. Newer circular polarizers have an additional thin sheet of material - quarter-wave - which lets the filter work properly with autofocus and newer auto-exposure cameras. Some people donít like circular polarizers, as the visual effect is subtly different from linear polarizers. But if you have a newer SLR, you donít have much choice.

I like polarizers for boosting the blueness of skies and increasing the contrast against white clouds. Though of course you can overdo it and get a tacky postcard sky look. Polarizers also cost you a stop or so of light, so you wonít want to use one in low-light conditions. Some people donít like polarizers because there are so many surfaces involved - the glass filters plus the plastic laminates - and this can cut down image quality.

Finally, you have to be aware that the polarizing effect varies depending on the sunís angle in the sky. You can view this effect directly by panning an SLR with a polarizer across an open blue sky - youíll notice at some points the polarizing effect is very pronounced, and at other points itís quite weak. If you have a really wide-angle lens (say 20mm or wider) youíll notice an uneven polarization effect across the sky as a result. Whether this detracts or not from your image is your call.
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