Filter Question...Need some specific insight

[freelanceshots]

Thanks for the help and responses. I appreciate it. Next is to buy one of these super expensive, mack daddy B + W pol filters and try it side by side to the other one. I

[Daniel Browning]

If you don

[freelanceshots]

I thought about that but did not see at B&H or Adorama if B+W makes a slim mount 82mm linear polarizer. I just looked where I did not see one. Shopping for filters at these online stores it kind of confusing. They have all these filters with many different prices where some say coated glass, some say multicoated glass, some say MRC coated glass and they all are Kaesemann. Then there is the thin glass and then there is the wide angle slim mount and then the regular mount. How do you know what you

[freelanceshots]

Just looked at B&H again and the offer a B+W 82mm Kaeseman Linear Polarizer Glass Filter (Extra Wide) for $244.00. Can

[Daniel Browning]

I wish I could be more help, but I can

[freelanceshots]

if you don

[neuroanatomist]

Can't find or understand what the explanation for the term Extra Wide means. From what I've understood in the past the slim mount is the one for really wide angle glass

B+W mounts are as follows:

• Standard (aka F-Pro) - 5 mm thick, has front threads (standard CPL is 8 mm thick)
• XS-Pro - 3.4 mm thick, has front threads
• Slim - avoids vignetting by being thin, 3 mm thick, no front threads (Slim CPL is 5 mm thick)
• Extra Wide - (referred to as oversize in the B+W handbook, but EW on the B+W web catalog), avoids vignetting by having larger diameter glass, 5 mm thick (I think), has front threads, filter glass is wider than lens thread (e.g. a 77mm oversized filter will have 77mm threads on the lens end, but the filter glass, and the front threads, will be 82mm).

So, the slim mount will generally do a good job at preventing vignetting, but the extra wide filter will do an even better job and is useful in cases where even a Slim filter would cause vignetting. I don't think you'd need an extra wide for any Canon lens, more likely for a wide angle medium format lens or a view camera.


Regarding the various types (and prices) of polarizing filters, the linear polarizers are always cheaper than the circular polarizers within a given mount size and optical quality. Mount sizes increase in price from standard to slim to extra wide. Optical quality increases in price from non-MRC to MRC toKäsemann. There are some gaps (e.g. none of the linear polarizers have the MRC coating). There's often a big jump from standard/slim to extra-wide, because the EW filters have larger diameter glass which adds a lot to the cost.


There's a description of their mounts, except the XS-Pro which is somewhat new, and more information including tables of which filters are available in which sizes and mounts, in the B+W Filter Handbook.

[freelanceshots]

That's every thing I need to know. Thank you for the answers to my questions. I can now make a more informed buying decision.


So you think in your opinion that the EW version in 82mm is overkill for the 5D2 and 16-35mm combination. The Slim mount filter should be what I need and be a little less expensive then the EW.

[neuroanatomist]

Glad to help!


I think you'd be ok with a Slim CPL - you might get a small amount of vignetting, though. Looking back over my post, I was thinking primarily of the UV filters, not CPLs. I don't have a 16-35mm to test (yet), nor an 82mm Slim CPL (although I will likely get one, since it will be useful on the TS-E 24mm I just got). Previously, I did some testing on filter mount thickness and vignetting on the EF-S 10-22mm (16-35mm FF equivalent angle of view). For the 10-22mm at 10mm, I could stack 8.4mm of filters (thicker than a standard CPL) with no mechanical vignetting. Of course, The EF-S lens is f/3.5 at the wide end, not f/2.8, and it's a smaller image circle, so it's not directly equivalent. I do notice that Bryan's vignetting results show a comparison of the 16-35mm II with no filter and with a B+W standard mount UV filter. There is a very small effect on vignetting (look at the EV line positions, not the overall brightness of the images, since the exposures appear a little different). Since the standard F-Pro mount is the same thickness as the Slim CPL, I'd expect you'd see similar results.


--John