Nikon 17-35mm and Polarizer

<p>I'm not happy with the overall coverage of my circular polarizing filters on my 17-35mm. I have the Moose's filter and just tried the B+W MC circular polarizer, both 77mm. Vignetting is not the problem, but the coverage is not even across. I shoot with a D300, so the angle is not that wide. I also thought the angle (not exactly 90 degrees) might be the cause, but I moved the angle and it still was unacceptable. Both shots in the example were shot at 17mm on my D300 (no post process). First the right and then the left had weak coverage. I also adjusted the polarizer several times to make sure it was on a correct line. At 17mm should this be a problem on a 77mm filter. I realize with the wide (12-24mm) this is a problem and don't use a polarizer on that one. Thanks ... Ray.</p><div></div>

<p>Uneven polarization is always a possibility with wide angle shots of the sky. It has nothing to do with your particular lens or polarizer.</p>

<p>Danny W.</p>

<p>I think that the problem in your images is that the FOV is too large. This is only a function of the FOV and not the polariser.</p>

<p>As far as I know there is no way around this other than a multiple exposure with a rotation of the polariser so as to get complete coverage.</p>

<p>With a large FOV a polariser does cover the whole image, but part of the image will not change at that angle of polarisation. In other words the polariser is not doing anything (that can be easily seen in the image) in certain portions of the sky/water etc.</p>

<p>Ray, I have a D300 and both lenses you mentioned. However, I don't see exactly what you mean by 'weak coverage' in the photos you posted.</p>

<p>If possible, maybe you could take similar shots with the polarizer on and off to show the difference. Also, I am curious if you see this same thing with the 12-24mm zoom at 17mm.</p>

<p> </p>

<p>Hi Bruce. My calibration may be off, but on my screen in the top photo the right corner the sky is much lighter than the rest. Inversely, in the bottom shot the sky in the left corner is lighter than the rest. Thanks ... Ray.</p>

<p><em>As far as I know there is no way around this other than a multiple exposure with a rotation of the polariser so as to get complete coverage.</em></p>

<p>Rotating the filter will help optimize the effect, but multiple exposures will not improve coverage. The sky is polarized in a band about 30-45 degrees wide, 90 degrees from the sun, due to the physics of scattered light. Similarly, light is most strongly polarized at a reflection angle of about 38 degrees (Brewster's Angle) from water and foliage. You can't improve on nature.</p>

<p>The best use of a polarizer is to reduce reflections in the foreground, which works over a much broader coverage and even on cloudy days. Using a polarizer to darken the sky is ineffective in hazy conditions (e.g., near the horizon), and often too extreme in very dry climates or high altitudes.</p>

<p>At 17mm this should be a problem regardless of filter size. It's often a problem with a 28mm, depending on the time of day.</p>

<p>At 17mm on a D300 the field of view is roughly equivalant to a 25-26mm lens on a FF (24x36mm) format. That is wider than the physics of polarizing light will work evenly across. About the widest angle lens on a FF (24x36mm) format that could have it's view evenly polarized is a bit longer, about 28-30mm or with the DX format, about 19-20mm.</p>

<p>Ray, they appear on my monitor to be about what you would expect. If you use NX2, you can adjust the light/dark areas of the sky using a color point to make the sky more even in tone and color. In CS3, you can achieve the same thing with a mask or the clone tool.</p>

 

Polarizers were made to work on normal to tele lenses, and usually do not work well on very wide lenses.

 

If you can mount something on a lens, it does not mean you should use it. You need to know how it will work on each lens and lighting conditions, as you have just discovered yourself - it does not work well in your case.

<p>Thanks to all. I didn't think 17mm on a D300 was that wide, but I guess it is concerning filters. I don't use polarizers on my 10-22mm. I was aware that this could be corrected in post, but was curious. Thanks again for the responses ... Ray.</p>

<p>For the reasons stated, as a general rule, polarizers should not be used on lenses wider than 35mm (full frame or 25mm on APS digital).</p>

<p>Capture NX2 and color control points. That will even turn the sky dark blue in between the individual leaves on the trees. Try that in CSX.</p>

<p> </p>

<p>If you including sky, you not supposed to use a polarizer from 20 and wider lens, otherwise you going to have uneven polarization on the sky or on the water, if this two is a main part of the image. Wider the lens, worst is the effect.</p>

<p>You can see the stripe in the right of the top frame. I also have heard that wide angle lenses of 20 or less distort the effect. But if this is a "circular" polariser, then I don't see why the band would just be on one side. Maybe a "linear" one got mixed up in the production process.<br>

Either way if the problem goes away on the removal of the polariser, then thats the problem, not the camera or lens, right?</p>

<p>Circular and linear polarizers have the same identical effect on the photo. A circular polarizer has a quarter wave plate (film) to "scramble" the polarization inside the camera so that the auto focus and auto exposure mechanism is not affected.</p>

<p>I often use a circular polarizer with my AF-S 17-35mm. The trick I learned to minimize the uneven coverage is as follows: find the maximum polarizing effect, then rotate the filter 10-20 degrees away from the max. This gives the nice polarizing effect while still reducing/removing the unwanted coverage issues. </p>