CPL on Big Telephoto (Zoom) ???

I have the Sigma 50-500mm = 95mm filter thread
Regardless of specific lens/camera, is anyone using a CPL on their big lens; and, if so, what brand/model CPL ?

Does anyone use this one; K&F Concept 95MM Circular Polarizer Filter HD 18 Layer Super Slim Multi Coated CPL Lens Filter:

https://www.amazon.com …huc_clickstream​_3_dp?th=1

It is a bit over my budget at $48.99; and, thus far, although there are 152 reviews, 72% 5-star, when I looked, there was not a single review specifically for the 95mm.

I've tried a CPL on my Canon 100-400 and the results at 400 were horrible. The 100-400 really did not like filters. Generally, long lenses do not do well with filters.

I don't understand (why a longer lens doesn't do well with filters). Personally I've not run into that.

On my 600mm, the filter is a very small drop-in at the back of the lens. I don't actually have any filters for that lens and have never tried to match a filter to it.

On my 200 - 400mm range, the filter size is 77mm. Quality filters can be pricy as they get bigger, but I've never once had a problem that I would attribute to a filter. I only use (fixed) ND or PL filters. My TS lens has a bigger front (82mm) and the filters were even more expensive, but that's a 24mm lens and probably doesn't match the question.

The only time that I've had problems with filters has been at the *wide* end because the effect of a polarizer varies across the frame when you go that wide. And I fully understand why that's the case...

gjl711 wrote in post #19065332
Generally, long lenses do not do well with filters.

That may very well be the case when the filter diameter starts getting in the 80-plus mm range.
One thing I have noticed when reading reviews on various filters is that, while the smaller diameter filters will have mostly 5-star reviews, when I read the 1-star reviews, they are almost 100% about the larger diameters; and, as a general rule, a long lens is going to have a large diameter objective, requiring a large diameter filter.

dasmith232 wrote in post #19065379
On my 600mm, the filter is a very small drop-in at the back of the lens.

Although I have never owned/tried one, I believe the concept of the filter inserting at the camera end of the lens is a good idea.
I have seen pictures of these type lens and have always considered it a good idea; of course, I would want to be able to stack filters and not be limited to one.

BuckSkin wrote in post #19065264
I have the Sigma 50-500mm = 95mm filter thread
Regardless of specific lens/camera, is anyone using a CPL on their big lens; and, if so, what brand/model CPL ?

Does anyone use this one; K&F Concept 95MM Circular Polarizer Filter HD 18 Layer Super Slim Multi Coated CPL Lens Filter:

https://www.amazon.com …huc_clickstream​_3_dp?th=1

It is a bit over my budget at $48.99; and, thus far, although there are 152 reviews, 72% 5-star, when I looked, there was not a single review specifically for the 95mm.

I mean this in the kindest possible way if $50 is over your budget, don't bother buying one. Cheap filters are the biggest cause of soft images, flare, poor focus response and a number of other maladies.

gonzogolf wrote in post #19065413
I mean this in the kindest possible way if $50 is over your budget, don't bother buying one. Cheap filters are the biggest cause of soft images, flare, poor focus response and a number of other maladies.

No offense taken and I mostly agree with that.
I read somewhere years ago that a rich man only has to buy once, whereas a poor man has to buy over and over again.

But then I will also say this, in this ever-changing age of quality import goods, there is a difference between "cheap" and "inexpensive" that years ago was not there.

And, the old saying "You get what you pay for" anymore is just that, an old saying; a poor man often does get what he pays for; but, it is also very easy to pay way too much.
I often see the exact same product on the same site selling for a wide range of prices; this tactic purely aimed at those who are afraid of paying too little.


As for high quality filters, I have often wondered why the lens manufacturers don't make/market them; at least, if they do, I have never been aware of it.

Canon does or at least did, because I once had a canon branded uv/protective filter. But given the ridiculous pricing of canon accessories I doubt they sell many.

I would feel more comfortable with bargain ND filters than the CP. Those are notorious for introducing focus issues.

There is one article I am looking for that clearly showed the impact of filters on long lenses but I haven't found it yet. I did find this one comparing a bunch of different filters and as a byproduct, shows the impact to IQ. For greatest impact, head to the bottom of the list.

gjl711 wrote in post #19065461
There is one article I am looking for that clearly showed the impact of filters on long lenses but I haven't found it yet. I did find this one comparing a bunch of different filters and as a byproduct, shows the impact to IQ. For greatest impact, head to the bottom of the list.

Thanks; I had not seen that particular test before.
Some time ago, I did see a similar test that included a much broader price range of filters, at least three times as many filters; and, the price ranged from very affordable to ridiculously expensive.
In that particular test, two mid-priced filters by the same manufacturer rated highest and a twelve-dollar filter was third place, with some of the very expensive filters ranking surprisingly poorly.
I am certain that I bookmarked it at the time, but I have about as many bookmarks as there are sites on the internet.

One thing in the article you linked to that sticks in my mind, way down toward the bottom in the several paragraphs of discussion, is the statement that the coatings on a lens filter are so thin that after a couple cleanings, even the best of them are no more than window glass.

Of course, that test is about UV filters and this discussion is about CPL filters; although without scientific testing equipment, I could probably not discern the actual UV reduction capabilities of a brand-new filter and one that had it's coating washed away, I believe that even I could tell whether a CPL was doing it's job or not.

Back to the meat of the question ---
Does anyone use a CPL on their long lens; and, if so, which one and your experience as to whether you feel it helps or hinders ?

Thanks for reading and all help is appreciated.