WA Circular Polarizer ?

[richard_clark8]

I read in other threads that some Circ Pols are physically unable to deliver

the right results at wide angles. I'm looking for 77mm filter to use at 16mm

and was wondering if there is one that offers better results.

 

Thanks

[kevinteo]

<p>It depends... 16mm on which format? Anything with a field of view wider than about

75° will result in even polarization.</p>

[kevinteo]

Oops... Should read "uneven polarization".

[richard_clark8]

It would be 16 mm on A Canon DSLR. (At this stage the 10mm end of a 10-22mm on a 400D. Shortly the 16mm end of a 16-35mm on a full frame 5D).

[Ed_Ingold]

The problem is with the nature of polarization, not the CPL itself.

 

The sky is polarized in a band centered at 90 degrees from the sun. The band is less than 45 degrees wide, which is OK for normal and telephoto shots. With a wide angle lens or panoramas, the polarized band will appear as a diagonal streak in the sky.

 

Light reflected from non-metallic surfaces (trees, rocks and dirt) is also polarized, depending on the angle of incidence. A polarizer removes part of the glare from these reflections, increasing the saturation and contrast of the subject. Since there are many diverse angles causing reflection, the effect is fairly consistent over a wide field of view.

 

IMO, using a polarizer to improve saturation in the ground or to control specular reflections is much more important than darkening the sky.

[mendel_leisk]

You will definetely get uneven results, at 10mm with 1.6 crop, or 16mm on full frame.

 

Even 24mm mm on full frame shows pronounced variation of sky darkening: in landscape orientation, maybe 50% of the sky darkened fully in the middle of the shot, and 25%/25% falling off to near normal brightness at the right and left ends. It's not that unpleasant/obvious, depends on the shot, but at 16mm (on full frame) it would be much more obvious.

[pvp]

The unevenness when using polarizers on wide angles is due to the nature of the sky, not the filter.

 

IOW, can't get away from it.

[richard_clark8]

Thanks guys. That's it I quit. No more Landscapes, I'm only shooting indoor portraiture from here on in. ;)