Different f-stop loss with various circular polarizers?

I own a 58mm circular polarizer. I now need a 77mm CPL to use with several of my lenses. Octen I will be shooting in early or late afternoon light. I understand polarizing ight and have searched and read many threads on circular polarizers. My question - at full (90 degree from sun) polarization - do all of the polarizers cause the same increase in required f-stop (i.e. have the same light loss)? How wide is the range? Any examples of what one gets for ~$70 vs. $225? I want good - but I don't want to buy features I can't properly value.

(BTW - once I get this 77, I may sell my 58 and get some step down rings for use on smaller diameter lenses).

I am positive they do. I assume any variance would be small and not measurable in "stops".

I shoot all day with the above mentioned sizes near the equator. I always get a 2 stop reduction.

ISTR someone's billing their polarizer as only needing 1-1/3 stops filter factor; how accurate the claim is, I know not. But by and large they all take about the same bite from your light. What you get for more money isn't a smaller filter factor, what you get is a better filter. It'll be multi-coated (less light loss due to reflection, up to 7%, and less susceptible to flare), and the glass will be better (more homogeneous, flatter, with parallel surfaces so no "lens effect" adding distortions and the glass won't be stressed (which will also cause distortions).

Thanks for confirming my suspicions on this subject. I fully understand and appreciate the multi-coat issues as well as glass quality (I actually am a ceramic engineer that has worked on furnace design for Corning, Schott - and more mundane glass items like Gallo wine and Miller beer bottles). I was just hoping I was missing something on how not to loose 2 f-stops on that beautiful sky, late afternoon shoot when trying to capture a moving object like a wild animal. I guess the answer is push the iso and use bood noise reduction software

Sometimes a polarizer isn't the answer with skies, it's properly balancing exposure.

I was asked by a customer recently how I got such wonderful skies with so much shadow detail. I was very thankful of the compliment and returned an answer this amateur photog could chew on.

My last words were "Oh and I use a polarizer too."

Don't be fooled into using it exclusively for bringing out the sky, use it in the arsenal to compliment your exposure skills. I meter for the sky often, birders can't, sportsshooter can't usually. I'm lucky that I take a lot of outdoor portraiture!

BUT.

I use a polarizer and flash to shoot trapeze. I use M and meter for sky with flash at full power. Know what your gear can do for the situation you're in and you get far better shots for yourself.