Camera Labs

Yesterday I've decided to take a polarizer filter on my 18-105mm for some street photography,because there was a lot of light (so loosing a few stops didn't matter) & the sun was in the right position for the filter to work well.
So I made a few tests first...the conclusion was that I was loosing sharpness. I know this shouldn't be normal,so what I am doing wrong?

Here's some examples,100% crops,of a taxi cab door:
-with polarizer
http://farm5.static.flickr.com/4059/457 ... 26e0_o.jpg
-without polarizer
http://farm5.static.flickr.com/4037/457 ... bba1_o.jpg

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Gear: Nikon D80, 18-105mm, 35mm F/1.8, 85mm F/1.8, SB-600
Visit my work here

Is it a brand polariser or a cheap one bought off eBay?

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Nikon D5000 and D300 with 12-24mm, 35mm f1.8, 50mm f1.4, 60mm f2.8 Macro, 18-200mm, 17-55mm f2.8 (all Nikon)

Hoya.
And in perfect condition,I might add.

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Gear: Nikon D80, 18-105mm, 35mm F/1.8, 85mm F/1.8, SB-600
Visit my work here

Can't tell from the small crops, but my suspicion is the focus is off on the with polariser sample. If you look at the original is another part in better focus?

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Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.

I've personally always found polarisers to slightly soften my images, i no longer use them and to protect the lens i use lens hoods instead.

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Mark Osborne
My life through an iPhone

All the sample "speak" of the same thing...softer images with the polarizer. I'm very dissapointed...& they cost me some serious money as well. I really thought that the glass in the polarizer filter doesn't affect the quality of the photos & no forum ever spoke about quality loss.

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Gear: Nikon D80, 18-105mm, 35mm F/1.8, 85mm F/1.8, SB-600
Visit my work here

Just did a test with the Hoya HD polariser. Canon 7D, ISO100, aperture priority f/5.6, EF 15-85 at 85mm, tungsten WB (I just wanted to be sure it stayed the same during test). I used AF without the filter in place to lock then switched the lens to MF for following shots, as my first attempt at this showed only that the shot to shot focus accuracy caused sharpness variation in itself. AF spot was over the right column of the crop. Tripod mounted, IS off, remote release. 100% crops.


No polariser or any filter.


Polariser in one random orientation.


Polariser rotated 90 degrees from before.

Spot the difference? To me there is a slight colour cast on the polariser shots, but I couldn't say there was any significant difference in sharpness in this test.

If you look at the exif, there is one stop light loss from the polariser.

Ok, I tested only one rather expensive polariser. I can't say that all will behave like this, but certainly this one doesn't appear to degrade the sharpness.

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Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.

This is even more annoying! My polarizer filters "drain" 3 stops. So unless my camera has some polarizer hate incorporated,the more expensive type of polarizers are the real deal.

Thank you popo for the tests!

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Gear: Nikon D80, 18-105mm, 35mm F/1.8, 85mm F/1.8, SB-600
Visit my work here

I guess I should add, in this condition the polariser had very little effect on the image. If you were shooting reflection conditions, then maybe the light loss would be more significant.

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Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.