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Post by squeamishossifrage on Feb 25, 2023 15:44:39 GMT
We all know the theory - they block polarized light in one plane, and reflections and scatterings are inevitably polarized to some degree, so they can be reduced or eliminated with a CPL. Aficionados of quantum theory will know that every natural light photon has its own random polarization, and although that may be at any angle, the process of polarization forces it to be either θ or θ+90° precisely, with nothing in between. In other words, exactly half the light gets through. We also all know that this just ain't true in the real world! Expect a loss of 1⅔ to 2 stops. Around ten years ago I read about a high transmission CPL filter claiming a much better performance - a Kenco Zeta CPL, so I bought one. It was an 82mm job, but I am hoping my arm and leg will grow back again in time.  The polarizing performance was not quite as strong as other CPLs I have, but there was always an exposure loss of only 1 or 1⅓ stops, and the filtration was always adequate for my needs. In fact, it became the 'protection filter' for my 24-70mm f:2.8 standard zoom, and hasn't been off except for artificial light conditions. I now want another one, this time a 67mm job for my 'light kit' 28-75mm f:2.8 zoom - but the current Kenco equivalent, the Kenko Zeta EX CPL is just the usual transmissibility, with no benefit at all over the Hoya CPL I am currently using, according to web reviews. I presume that the market preferred high polarization over high transmission - or the reviewers did, anyway - so Kenco went with the flow. I have also been unable to find any recent reviews that grade transmissibility of various potential candidates. If anybody has any suggestions to make, I would be very grateful. An only modest degree of polarization, for me, is a good trade-off for less light loss. |
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Post by peterob on Feb 25, 2023 16:09:25 GMT
I've never really got on with polarising filters but then I've tended to use them with over-wide lenses and ended up with uneven and too-blue skies. A loss of 5/3 stop is roughly what I'd expect but I vaguely remember an old thread on AP where there were multiple disagreements on this. I've never bothered to use CPL for vegetation to reduce reflections - maybe if I did much flower photography I'd think differently. Raw processing now can change sky luminance and hue more than adequately. Reducing reflections would seem to be the main (specialist) use.
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Post by Fenris on Feb 25, 2023 17:12:47 GMT
Do you still have the 82mm one?
If so, try and find a stepper ring that goes from 67mm to 82mm
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Post by Chester PB on Feb 25, 2023 17:27:41 GMT
I've never really got on with polarising filters but then I've tended to use them with over-wide lenses and ended up with uneven and too-blue skies. A loss of 5/3 stop is roughly what I'd expect but I vaguely remember an old thread on AP where there were multiple disagreements on this. I've never bothered to use CPL for vegetation to reduce reflections - maybe if I did much flower photography I'd think differently. Raw processing now can change sky luminance and hue more than adequately. Reducing reflections would seem to be the main (specialist) use. With a wide angle lens, once you go wider than16-18 mm 'equivalent focal length', a PL filter will be useless because it will give uneven results across the image. Many years ago, after one of AP's glowing articles about these filters, I spent far to much money on one to fit my Sigma 10-20 lens. It was fine at 20 mm, but useless at 10-13 mm, so was an expensive mistake. I later found a nice (and much less expensive) circular ND graduated filter which has since lived permanently on the lens, and works perfectly because you can get a lot of sky in shots with a lens like this. If I want to rotate it, I just unscrew it a little until it is at the right position. AP did another article 2 or 3 years ago about PL filters, without warning potential buyers about the problem with some wide angle lenses, and an edited version of my email to the magazine about this was published. Since then, I have noticed in other articles about PL filters, the warning is sometimes included. Perhaps I don't take shots where the remove of reflections is important: I often look for them because I want them there. |
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Post by squeamishossifrage on Feb 26, 2023 7:15:01 GMT
Do you still have the 82mm one? If so, try and find a stepper ring that goes from 67mm to 82mm Yes, I do, and I also have a pair of stepper rings to take me from 67mm to 82mm. The problem is, of course, that l would have to loose the lens hood, and if you need a CPL, then you almost certainly need a lens hood too. |
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Post by Fenris on Feb 26, 2023 11:51:11 GMT
Do you still have the 82mm one? If so, try and find a stepper ring that goes from 67mm to 82mm Yes, I do, and I also have a pair of stepper rings to take me from 67mm to 82mm. The problem is, of course, that l would have to loose the lens hood, and if you need a CPL, then you almost certainly need a lens hood too. Ah... good point. I don't suppose you could "Heath Robinson" something that could act as a temporary lens hood? |
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Post by petrochemist on Feb 26, 2023 12:09:00 GMT
Do you still have the 82mm one? If so, try and find a stepper ring that goes from 67mm to 82mm Yes, I do, and I also have a pair of stepper rings to take me from 67mm to 82mm. The problem is, of course, that l would have to loose the lens hood, and if you need a CPL, then you almost certainly need a lens hood too. You could always fit a 82-67 (or 72) step down on the other side of the CPL and try a hood on that.  I've never tried one of the high transmission polarisers, though I have loads of the high extinction types. I don't use them that often but when I do they work magic. |
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Post by kate on Feb 26, 2023 12:27:02 GMT
Using one of those always found me tweaking it this way and that and finally unscrewing it.
I used to be the same sighting my target rifle shots and fiddling with the screws. I used to give up on that too and just shoot. Ha!
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Post by stevewmh on Feb 26, 2023 16:57:07 GMT
Dropped one in the pond at Coxes Mill pond while farting about adjusting it, it unscrewed and fell off
At nearly 50 quid, off came the shoes and socks rolled up me trouser legs and paddled in
Surprisingly it survived the dunking perfectly well. The seal between the two glass elements must be pretty good as no water got in
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Post by squeamishossifrage on Mar 9, 2023 12:34:30 GMT
I Googled and Bingled and Duck-duck-went for hours looking for a high transmission job to no avail. Then today, when opening a new tab in MS Edge which always starts with news and ads that MS think are appropriate for you, the main item was an ad for a B+W CPL High Transmission Master filter made in Germany. A review on Fstoppers confirmed that in normal use it loses just one stop, rising to a maximum of 1.5 for very high reflectivity scenes. I am now scouting various on-line suppliers for the best deal - looks like Amazon.de, who have just informed me I was looking for the wrong thing. Apparently I should have been asking for 'b+w polfilter hochgetriebemaster 72 mm'. I guess they would know.  |
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The polarizing performance was not quite as strong as other CPLs I have, but there was always an exposure loss of only 1 or 1⅓ stops, and the filtration was always adequate for my needs. In fact, it became the 'protection filter' for my 24-70mm f:2.8 standard zoom, and hasn't been off except for artificial light conditions.
