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03-31-2012, 09:41 PM   #1
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CPL filter selection

I am going to select a CPL filter for my DA12-24 lens. However, I noticed there are so many options on ebay that the price range from $7 to $170. Certainly I am not going to choose based on price. But don't want to spend too much money on it. I would start looking from $50.

Please tell me the $50 filter is much worse then the $170 one? What are the differences between those filters? And which one would be the best choice? Thanks

03-31-2012, 11:52 PM   #2
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Marumi DHG Super Circular P.L.D

Polarizing filters test - Introduction - Lenstip.com
12-26-2012, 07:51 PM   #3
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Good question. I'd like to hear some opinions also. The Lenstip site only tests the more expensive CPL's. I'd like to know if there are any CPL filters in the $10 - $40 range that are adequate or if they are all a waste of money.

If the cheapo's are a complete waste of money, what is it that they do/don't do? Do they distort the image, cause it to lose sharpness/focus, difficult to focus, etc.?

I'm an amateur and am just now trying to learn some of the finer points in photography after toying around with it off and on for many years. I'm using the K-r with DAL 18-55mm and the DA 50-200mm.
12-26-2012, 08:47 PM   #4
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I'm not sure its a good idea to put a polarizer on such a wide lens - it will make the sky unevenly dark. Try a relatively cheap brand first, see how you like it.

12-26-2012, 08:54 PM   #5
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I'm a firm believer in spending good money on a filter; this is truly an instance of getting what you pay for. Otherwise, it's like putting bargain tires on a Mercedes; the vehicle handles only as good as the tires. If you want great polarizers, look into Singh-Ray or B+W. I don't put any polarizers of lesser quality on my quality lenses.
12-26-2012, 08:54 PM   #6
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QuoteOriginally posted by Na Horuk Quote
I'm not sure its a good idea to put a polarizer on such a wide lens - it will make the sky unevenly dark. Try a relatively cheap brand first, see how you like it.
Consider also that you don't really need to get a circular polarizer. A linear will do just fine with Pentax cameras. They used to be significantly cheaper than circular ones for similar quality, I don't know if this is still the case.
12-27-2012, 07:17 AM   #7
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The drawback with non-CPL filters is an apparent effect on some AF systems. With the DoF of WA lenses used outdoors for landscapes with moderate apertures manual focus is certainly an option. However as stated above, the broad coverage of WA lenses causes unwanted variations in exposure and sky effects.

Used to control reflections in close work, either filter type will serve. Metal reflections aren't generally reduced, water in nature shoots is a good example of non-sky use.

Best advise above was to get a cheap one and see how it serves your needs first.

H2
12-27-2012, 08:20 PM   #8
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Hello OHCE, I had a pleasant surprise buying real GLASS 77 mm CPL & GND Filters for my Sigma 10-20 zoom lens. Beautiful fit & finish, with dampened rotation of the front ring. I also bought a 77 to 67 mm adapter ring for $ 1.70 shipped, for use on the Tamron 28-75 zoom. I have attached photos and you can judge the results for yourself.
Lets face it, how many times in a year would one use CPLs & GNDs? Why pay a heavy price when you can good results cheap? Why pixel peep? And I am not a pro, just an advanced amateur.
I also have very expensive 52 mm B&W CPL and a mid priced Marumi 72mm. Believe me I did not find much great difference.
Regards. Bipin.
camp; Thornhill, Ontario, Canada.


Last edited by nanhi; 03-25-2013 at 11:41 PM.
12-27-2012, 09:10 PM   #9
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I tested a variety of CPLs and posted about them HERE.
12-28-2012, 03:50 PM   #10
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Careful of the LensTip polarizer test...if I remember correctly those were shot at night looking at streetlights. Distortion wasn't tested and streetlights have a very limited spectrum rendering the color accuracy stats irrelevant. How does white snow look through a polarizer? Often, not white...and those attempted tests didn't analyze it with any of the brands...
01-04-2013, 11:56 PM   #11
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I pretty much only bother to use my CPL when I'm taking waterfall shots. Additionally I would only buy a namebrand multicoated filter. Unfortunately that is pretty expensive for a 77mm filter.
01-05-2013, 12:27 AM   #12
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QuoteOriginally posted by Na Horuk Quote
I'm not sure its a good idea to put a polarizer on such a wide lens - it will make the sky unevenly dark. Try a relatively cheap brand first, see how you like it.
X2

I would not use a polarizer on a wide lens that has sky in it. 24mm(APS) or 35mm(FF) is about as wide as I would go. I burned a lot of film to figure that out. It will work fine for eliminating reflections from glass or water with a wide lens.

Light entering our atmosphere is polarized. It is strongest at 90* to the sun and weakest close to the sun and at 180*. As polarized light passes thru the polarizing filter, the more highly polarized light is rendered darker and the lesser polarized light is not rendered as dark. The angle of polarization changes radially across the sky and up and down from the horizon.

The angle of the polarization of the filter is only manifest in one direction, allowing you to most strongly affect only the light polarized at right angles to your filter.

You have the varying strength and angle of polarization across different regions of the sky. Your filter can only affect one portion strongly!
01-09-2013, 12:21 PM   #13
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QuoteOriginally posted by Billy525 Quote
Good question. I'd like to hear some opinions also. The Lenstip site only tests the more expensive CPL's. I'd like to know if there are any CPL filters in the $10 - $40 range that are adequate or if they are all a waste of money.

If the cheapo's are a complete waste of money, what is it that they do/don't do? Do they distort the image, cause it to lose sharpness/focus, difficult to focus, etc.?

I'm an amateur and am just now trying to learn some of the finer points in photography after toying around with it off and on for many years. I'm using the K-r with DAL 18-55mm and the DA 50-200mm.
Bad filters may have several shortcomings, which are emphasized by a CPL, as it has two glasses or 4 surfaces:
  1. a good multi-coating is indispensible, as that reduces glare and ghosting (unwanted reflections of any specular highlights) very visibly
  2. to machine 4 surfaces to exacting standards (flat, plano-parallel, without surface ripples) is time consuming and expensive, accordingly a manufacturer who meets certain minium standards needs to cash-in a minimum amount of money.
    -- if the surfaces are not realy flat and have a rippled surface, which is often the case with "flame polished" glass, you will have a loss of detail in the resulting image
    -- if the 4 surfaces are not plano-parallel, they form a kind of wedge shape. That is a prism. You do not want a prism in front of your lens, if you don't plan to use it on purpose...
  3. The foil, sandwhiched between the two glass elemets should be resistant to aging (longevity of the filter) and it should be homogenous and it should be colour neutral - which it isn't in many cheaper filters. I can certainly testify, that the Cokin CPL itroduces a visible and hardly correctable colour shift, to name just one example.

Anyway, if one spents a lot of money on a good lens, why then throw away its optical quality, using an inferior filter. A good CPL will last decades and you will be satisfied with the results. A bad filter will be used for novelty and then put away and you'll miss a lot of opportunities.

By the way, a really good filter does not need to be extraordinarily expensive. A Kenko Pro1 (the same as the Hoya, just under a second brand name) or a Marumi from their top line, both are not really expensive, but will provide solid results.

Ben
01-09-2013, 12:41 PM   #14
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Ben, as a Graduate Engineer and a retired Advisor in one of the worlds biggest conglomerate, I am perfectly in agreement with your technical explanation of the process of manufacturing good CPL filters. I am not a pixel peeper and just an amateur photographer. So can you please see my photos attached above and comment on them. The first photo is with a CPL (the cheapest in the world, the 2nd with the GND (world's cheapest) and the 3rd is without. Note I also have expensive B&W + Marumi CPLs, and did not find much difference, at least not (10) times the difference based on the price. Yes there is a difference, but hardly noticeable to the naked eye.
Await your comment on the photos. Exif data is attached.
Regards. Bipin.
camp:Thornhill, Ontario, Canada.
01-15-2013, 01:35 PM   #15
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QuoteOriginally posted by nanhi Quote
Ben, as a Graduate Engineer and a retired Advisor in one of the worlds biggest conglomerate, I am perfectly in agreement with your technical explanation of the process of manufacturing good CPL filters. I am not a pixel peeper and just an amateur photographer. So can you please see my photos attached above and comment on them. The first photo is with a CPL (the cheapest in the world, the 2nd with the GND (world's cheapest) and the 3rd is without. Note I also have expensive B&W + Marumi CPLs, and did not find much difference, at least not (10) times the difference based on the price. Yes there is a difference, but hardly noticeable to the naked eye.
Await your comment on the photos. Exif data is attached.
Regards. Bipin.
camp:Thornhill, Ontario, Canada.
Hi Bipin

Thank you so much for providing the comparative images. Nevertheless, I feel unable to comment on the possible differences in image quality. Firstly, the size is too small and secondly the images are heavily compressed, which has potentially more influence on IQ, than the different filters.

But I will take up your notion, that you can detect a minor difference. And indeed the real question is, how much of a compromise is one willing to accept. As always in life the first 80% of something will cost 20% of the price, but the remaining 20% of something will cost 80% of the price. So, personally I know, that any added glass in front of my lenses will cost me some degradation. But I want that amount of IQ loss as minimal as possible. I once ruined a whole night of picture taking in London, because I forgot to remove the "protective" UV-filters. And every single shot had severe ghosting somewhere in the image frame. Since that day (or better, since the day I got my slides back from the lab), I try to avoid to use filters and when I need one, I opt for the best.

Why hundreds and thousands for good lenses and then reduce their potential with a cheap filter? I buy less equipment today, than when I started seriously with photography, becaiuse I buy better equipment, that serves my needs over many years.

And when I print my images, I usually print as large as possible, and then I am pretty happy, that I did not compromise more, than I am forced to (any lens is a compromise, as we all know).

So, if one uses cheap or mediocre lenses and does only print the standard 4x5 or 5x6 lab print sizes, I guess, that using cheap filters won't show up as being an annoyance. So it melts down to personal preferences and sensibilities and satisfaction levels.

That is not meant to critisize anything or anybody, but I think, a simple fact of life.

Ben
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