Photo: Roger Cicala/Lens Rentals

Our friend Roger Cicala over at Lens Rentals is at it again: buying up super expensive optical testing equipment because someone asked him why LR carries the circular polarizing filters they do. The answer, until now, was simple: make the expensive one on the market their high-end rental, and the cheapest one their "basic." But is there really any difference?

That's what Roger set out to figure out, and the answer might save you a little bit of cash.

You can read the full post and see all of the detailed results on the Lens Rentals blog, but the most surprising and positive conclusion was this:

All circular polarizers, regardless of price, are 99.9% effective at polarizing light.

Translation: if you're looking for a circular polarizer because ... well ... you want to polarize light then save your money because the cheaper ones work just as well as the more expensive ones.

In addition to their ability to do what they say they do, Cicala and LR team tested CP filters for overall transmission (how much light to they let through) and transmission by wavelength so you can see what effect each filter has on the colors your camera sees. Check out the results here.