polarizing filter phenomenon and medium format

[kevinbriggs]

<p>Question regarding the following negative effect of using a polarizing filter on a wide angle lens -- which is explained best by the following quick photo example found <a href="http://www.the-digital-picture.com/Reviews/B-W-77mm-MRC-Circular-Polarizer-Filter-Review.aspx">here</a> (middle of the page):</p>

<p>Are there any specific "cut off" technical specifications for exactly when such a phenomenon will occur...? Meaning, does it occur on all wide-angle lenses, or is it a very specific in its appearance once you have crossed a certain technical threshold, as it were...?</p>

<p>I shoot primarily with wide angle lenses; I have been shooting in 35mm format (Canon 1Ds Mark III) for the past several years, but I'm now moving to the Mamiya medium format range in the near future.</p>

<p>Is there a difference with how this polarizer-filter phenomenon occurs with relation to the difference between 35mm and medium format (6 x 7 cm), or does this not have any appreciable difference (which is my guess)...?</p>

<p>Thanks in advance!</p>

 

[adrian_wilson9]

<p>Hi Kevin,<br>

I have polarizers up to 105mm and also Cokin X-pro, to be honest I have never given it much thought about wide angle lenses, but yes if you are covering an unusually wide area and that happens to include clear blue sky you are bound to see an aberration as polarizers work best at a specific angle and reaching past that permitted range could well produce a marked loss of polariszation on your image as you describe. I very rarely use the Cokins because the blue tint is obtuse, I prefer a cheapo version the gives me the colour rendition I.m looking for without the image shouting POLARIZER !</p>

<p>Cheers,<br>

Adrian<br /></p>

[lachaine]

<p>It has nothing to do with the actual lens or wide angle as such. It's because polarized light changes so much over a wide field of view that it becomes obvious. When you see the banding this produces, it's not an aberration or an artifact, it's just accurately reproducing what nature does in terms of polarized light. The film format has nothing to do with it, if you end up framing the same wide angle.</p>

[david_henderson]

<p>I quite often get this effect with 50mm ( and wider) lenses for my 6x6. I don't really see it with the 80mm. If you simply want to deepen blue skies then a grad is a better bet with wide lenses, but clearly that won't do everything a polarising filter does. </p>

[paul ron]

<p>Polarisers work at 90° to the sun for a small portion of the view. As you go 45° on either side the polarisation area, it tapers off. So anything wider than aprox 45° of the sweet spot will look unpolarised, as you put it, produce a narrow band. </p>

 

[jim_momary]

<p >Pretty much as discussed, depends on the direction and the amount of sky taken in.</p>

<p >With 6x7, 50mm = 82^oFOV, 90mm = 68^o, 127mm = 38^o and 180mm = 28^o. (approx.)<br>

I still see some banding with the 90mm, but seldom with the 127mm. So, anything taking in less than 45^o is a safe statement to avoid the noticeable appearance of banding. (in my opinion)<br>

Two crappy examples below.<br>

Jim</p><div></div>

[stp]

<p>I've used polarizers on large format, medium format, and 35mm. Great care has to be taken with using the filter on a wide angle lens when the sky is in the photo. I simply don't use a polarizer under such conditions. I will use it on a wide angle lens in, say, the interior of a forest when the goal is to reduce vegetation glare and increase saturation. But the unevenness a polarizer causes when a wide portion of the sky, particularly at approximately right angles to the sun, is included simply isn't worth it -- the results are, IMO, unappealing.</p>

[kevinbriggs]

<p>I've learned to rely more on ND filters for such situations but was hoping there was a successful technical methodology for those instances when I need the positive polarizing effects associated with water (in the foreground).</p>

<p>Thanks for all the responses! Much appreciated.</p>