How do you measure the quality of a polarising filter ?

Graham Roberthall

Graham Roberthall

Suspended / Banned
Messages
53
Name
Graham
Edit My Images
Yes
I am not so much talking about image quality as the policing affect. I have a cheap £20 polariser, an expensive Hoya HD and an even more expensive B+W and it seems to me that the more you pay the less ( or perhaps 'more subtle' ) the effect is on the sky and clouds...... I don't understand why that would be.

Any explanations ?
 
Graham Roberthall said:
I am not so much talking about image quality as the policing affect. I have a cheap £20 polariser, an expensive Hoya HD and an even more expensive B+W and it seems to me that the more you pay the less ( or perhaps 'more subtle' ) the effect is on the sky and clouds...... I don't understand why that would be.

Any explanations ?
Click to expand...

In terms of pure polarising ability, there is no difference between brands. No difference between linear and circular polarisers either, no difference between the lighter-toned variety and the more common slightly darker types, and I've never read any manufacturers' claims to the contrary. Controlled side by side testing will confirm this, in constant conditions, with careful attention to precise angle to the light and exact degree of rotation. If you're seeing differences, I'd guess it's the degree of rotation and exposure that's the variable but also outdoors the sky and position of clouds will change by the second.

I've tested maybe 20 different polarising filters through my work, and the differences are in the other areas, mostly the kind of things that that apply to all filters.
 
Last edited:
Interesting HoppyUK, I did not know that. Many thanks for sharing that.
 
HoppyUK said:
In terms of pure polarising ability, there is no difference between brands. No difference between linear and circular polarisers either, no difference between the lighter-toned variety and the more common slightly darker types, and I've never read any manufacturers' claims to the contrary. Controlled side by side testing will confirm this, in constant conditions, with careful attention to precise angle to the light and exact degree of rotation. If you're seeing differences, I'd guess it's the degree of rotation and exposure that's the variable but also outdoors the sky and position of clouds will change by the second.

I've tested maybe 20 different polarising filters through my work, and the differences are in the other areas, mostly the kind of things that that apply to all filters.
Click to expand...

Hoppy, just one thing, you need to use a circular polariser with AF on a DSLR or it won't AF......

George.
 
HoppyUK said:
In terms of pure polarising ability, there is no difference between brands. No difference between linear and circular polarisers either, no difference between the lighter-toned variety and the more common slightly darker types, and I've never read any manufacturers' claims to the contrary. Controlled side by side testing will confirm this, in constant conditions, with careful attention to precise angle to the light and exact degree of rotation. If you're seeing differences, I'd guess it's the degree of rotation and exposure that's the variable but also outdoors the sky and position of clouds will change by the second.

I've tested maybe 20 different polarising filters through my work, and the differences are in the other areas, mostly the kind of things that that apply to all filters.
Click to expand...

"In terms of pure polarising ability, there is no difference between brands."

In case anyone didn't believe me, here's a very thorough test of polarising performance that comes to the same conclusion, though it doesn't comment on all the other important things that go into making a top quality filter. From Lens Rentals blog, via DPReview
https://www.dpreview.com/news/79960...izing-filters-work-great-price-doesn-t-matter
 
Eloise said:
https://www.lensrentals.com/blog/20...tertaining-circular-polarizer-filter-article/ might be of use. It notes that all the filters at various prices polarise the light properly, however the light transmission varied - interestingly though the best (the B+W) and worse (the Tiffen) for light transmission cost within a dollar of each other.

(Sorry I see Richard posted the dpreview link to the same article)
Click to expand...

No worries Eloise :)

Of all Roger Cicala's excellent and entertaining reviews, that one on polarising filters is the least helpful in that it doesn't really tell us anything we didn't know. I've been writing in magazine reviews for years, and on here, that all CPLs polarise the same, and that shouldn't really come as a surprise because no manufacturer that I'm aware of has ever claimed a performance advantage in that area.

I don't really understand his transmission figures. There are basically two types of polarising material used: the lighter toned variety that has a neutral density value around 1.2 stops and a slightly warmer tone, and the traditional darker variety that I've tested at anything from 1.7 to 2.1 stops and sometimes with a hint of blue cast. You can see that clearly enough in the photo at the bottom of Roger's test, but his transmission percentages don't match up at all.

That aside, what we really want to know about is optical quality that can affect sharpness with long lenses, and particularly coatings that can have a big impact on flare and ghosting performance. Also the effectiveness of water-repellent easy-clean coatings. On all those things though, I've not found significant differences between the best versions from the leading brands. Personally I'm not bothered about brass or aluminium mounts, or whatever design of knurling is used for the finger grip - six of one, half dozen of the other. The thickness of the mount is important though when used with wide-angles.

FWIW, I prefer the lighter toned CPLs, with multi-coating and an easy-clean top surface. Then might as well go for the cheapest, in a slim-profile mount (making sure it has front threads to attach the lens cap). Top end versions from Hoya, B+W and Marumi are all excellent.
 
Last edited:
You must log in or register to reply here.
Back
Top