# Question on B+W Circular Polarizer



## pensive tomato (Jun 6, 2013)

I went FF a few months ago, and I keep running into all the small things that have changed (mostly for the positive). Nonetheless, now my trusty B+W F-Pro c-pol is vignetting on my 24-105mm at 24mm even if the lens is stopped down.

I saw some old postings on going for the XS-Pro mount instead. For those experienced using B+W c-pols, would the B+W XS-Pro Kaesemann Circular Polarizer with Multi-Resistant Nano Coating work the best? Is there a slim version of this filter that I should get instead (I don't usually stack filters)?

Thanks for the help, as I'm already a bit pissed at myself for having to buy this kind of filter twice.


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## neuroanatomist (Jun 6, 2013)

Get the XS-Pro CPL. Your F-Pro CPL is 7mm thick, the Slim version is 5mm thick, and the XS-Pro version is only 4mm thick.


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## pensive tomato (Jun 6, 2013)

neuroanatomist said:


> Get the XS-Pro CPL. Your F-Pro CPL is 7mm thick, the Slim version is 5mm thick, and the XS-Pro version is only 4mm thick.



Thanks a lot, Neuro, this is precisely the info I was looking for!


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## KyleSTL (Jun 6, 2013)

neuroanatomist said:


> Get the XS-Pro CPL. Your F-Pro CPL is 7mm thick, the Slim version is 5mm thick, and the XS-Pro version is only 4mm thick.


Excellent information neuro, I had always assumed that the slim was the thinnest due to the use of the slip-on cap, and the XS Pro had to be thicker due to the front filter threads. This might change my decision when I go to buy a CPL, ND, or any other filter that will just be used occasionally. Do you know if this holds true for all sizes, or just the 77mm?


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## neuroanatomist (Jun 6, 2013)

True for all sizes. Those thicknesses apply only to the CPL's, though. For other filters, the XS-Pro is slightly thicker than the Slim. Here are the numbers...


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## mariusx1 (Jun 10, 2013)

Thanks for the info, neuro. I was moments away from ordering the B+W Kaesemann CPL when I say this thread. Now, I want to make sure I get the right one.

I'll be using this new CPL on my 24-105mm as well as my 17-40mm. Does the base Kaesemann model use the F-PRO mount and therefore cause vignetting as well? Should I spend the extra $50 on the XS-PRO version?

77mm B+W Kaesemann CPL
http://www.bhphotovideo.com/c/product/10889-REG/B_W_66_045620_77mm_Kaeseman_Circular_Polarizing.html

77mm B+W Kaesemann XS-Pro Nano CPL
http://www.bhphotovideo.com/c/product/752975-REG/B_W_1066400_77mm_XS_Pro_Digital_MC.html

EDIT: I think I found my answer on the B+W website. The base Kaesemann (first link above) does indeed use the thicker F-Pro mount. But, I also found several forum posts of people using it on a 17-40mm without any vignetting (at 17mm).


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## RGF (Jun 13, 2013)

Just checking, that you are stacking filters. That can cause vignetting


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## RGF (Jun 13, 2013)

neuroanatomist said:


> True for all sizes. Those thicknesses apply only to the CPL's, though. For other filters, the XS-Pro is slightly thicker than the Slim. Here are the numbers...



Hi NA

Are you the maven of all things photographic, or just spend time searching data for us? ;D


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## neuroanatomist (Jun 13, 2013)

RGF said:


> Are you the maven of all things photographic, or just spend time searching data for us? ;D



I have excellent Google-fu, I read a lot, I read fast, and I remember almost all of what I read (and where to find it again). It's a scientist thing.


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## RGF (Jun 13, 2013)

neuroanatomist said:


> RGF said:
> 
> 
> > Are you the maven of all things photographic, or just spend time searching data for us? ;D
> ...



Scientist in what?


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## neuroanatomist (Jun 13, 2013)

RGF said:


> neuroanatomist said:
> 
> 
> > RGF said:
> ...



Drug development in oncology, neuroscience, and respiratory/immunology.


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## Malte_P (Jun 13, 2013)

RGF said:


> neuroanatomist said:
> 
> 
> > RGF said:
> ...



more important.. where does he work?
it´s seems he is 24/7 online here.... must be not a very time intensive job. ;D 

i wish i had that much spare time.


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## RGF (Jun 13, 2013)

neuroanatomist said:


> RGF said:
> 
> 
> > neuroanatomist said:
> ...



Impressed


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## wsheldon (Jun 13, 2013)

pensive tomato said:


> I went FF a few months ago, and I keep running into all the small things that have changed (mostly for the positive). Nonetheless, now my trusty B+W F-Pro c-pol is vignetting on my 24-105mm at 24mm even if the lens is stopped down.
> 
> I saw some old postings on going for the XS-Pro mount instead. For those experienced using B+W c-pols, would the B+W XS-Pro Kaesemann Circular Polarizer with Multi-Resistant Nano Coating work the best? Is there a slim version of this filter that I should get instead (I don't usually stack filters)?
> 
> Thanks for the help, as I'm already a bit pissed at myself for having to buy this kind of filter twice.



Interesting. I just tried out my 7 yr old B+W F-Pro 77mm on my new 6D + 24-105 and didn't get any noticeable filter vignetting at 24mm. I saw the expected 2-3 stop vignetting at wide apertures (as on the naked lens), and very slight vignetting at 8-10 (~1 stop), but that's normal at 24mm based on lens reviews I've read. Using the lens corrections in LR eliminates corner vignetting anyway, because the distortion correction at 24mm clips the extreme corners right off, but I didn't really find that necessary for most images.

In my past experience filter vignetting is black and hard, not just 1-2 stops as I experienced. Did you check to make sure the filter was thoroughly screwed in, and that your hood was properly aligned? I wonder if this thicker filter is right on the edge in terms of vignetting, and slight variations in lenses or filter installation make the difference.

I'm sure the XS-Pro Kaesemann is a great filter, but at $160 I think I'll stick with the F-Pro and be prepared to crop a tiny bit if I ever get bit by vignetting.

Good luck.


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## Vossie (Jun 13, 2013)

The ksm version is also available with xs-pro mount.


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## brad-man (Jun 14, 2013)

+1 for the XS-Pro

It's also worth mentioning that B&W's slim filters don't accept any pinch type lens caps. They come with Tupperware-like caps that won't stay on. On the other hand, they do make for a fine drink coaster.


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## EOBeav (Jun 14, 2013)

Malte_P said:


> more important.. where does he work?
> it´s seems he is 24/7 online here.... must be not a very time intensive job. ;D
> 
> i wish i had that much spare time.



Who knows. Except for the occasional lapse in spelling, he's a smart dude. I've seldom had reason to doubt his advice, and when he has an opinion on something I stop to make sure I'm thinking through my own correctly. Ignore his comments at your own peril, but you're not going to find better free advice anywhere else.


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## Powder Portraits (Jun 14, 2013)

For what it’s worth I use both the 24-105 and a B&W slim Polarizer for years without issue, and still have the original cap.


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## serendipidy (Jun 14, 2013)

EOBeav said:


> Malte_P said:
> 
> 
> > more important.. where does he work?
> ...



Totally agree...and sarcasm that is often entertaining.
I think he works in Bean Town (Boston)


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## Rofflesaurrr (Jun 14, 2013)

Pardon my ignorance, but would using a larger filter with a a step down ring prevent vignetting?


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## Rienzphotoz (Jun 14, 2013)

neuroanatomist said:


> I have excellent Google-fu, I read a lot, I read fast, and I remember almost all of what I read (and where to find it again). It's a scientist thing.


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