UPDATE 12/21/2019:Please see review updates below leading to this latest update and a change for my review for this filter to 5 stars:First to say Jongsun did an awesome job for supporting a customer with issue on their lens. They stayed in touch with me all the way from China and got a replacement filter to me to test out and review accordingly. Julia there even apologized for the gap of delay due to time zone differences, although that courtesy wasn't needed.After testing over a week with and without this filter using controlled conditions, on a tripod, shutter speeds at least 1/1000 sec or faster. Focus verification on the exact same spot for with and without filter comparison, the images were unedited and un-sharpened RAW images and all looked identical filter on or off, at 600mm. The replacement, although the packaging and filter itself were identical to my precious filter that had the issues, "clearly", (no pun intended) did NOT degrade my Sigma at 600mm, the worst case for the issues I had with soft images and lack of sharpness/detail prior to the replacement.Haze filters that are ruining the Sigma 150-600mm (as well as the Tamron equivalent and the Nikon 200-500mm as well)are out there in forums......it is not chronic, but, then again, not everyone has a super-telephoto and thus, might never see an issue with a lower focal length telephoto.So in summary, the replacement that Jongsun sent me and in only a few days, resolved my issues.The filter is thin profile as many have said, but, no issues on my Sigma. The threads are fine and "dry".....so be gentle threading these on. I typically place the filter on the lens and gently turn it first counter-clockwise until I feel the slight "click" where the correct entry point on the thread alignment are for lens and filter and then begin screwing it in clockwise. this system has always worked well for me; no jams or cross-threading.So in summary, a great filter and a great company who stands behind their product and is willing to bend over backwards to try to resolve issues for their customer. I will be ordering a few more of their lenses for some upcoming new glass some time next year. JONGSUN has earned my continued business. Well done!UPDATE: 12/13/2019. JONGSUN contacted me and graciously provided another replacement for me to test my Sigma 150-600mm Contemporary lens with. That test is in progress and I will update this review accordingly w/i a few weeks . (by end of 12/2019).Given the excellent customer support and effort to try to resolve my issue with a replacement which they have provided, I will state, ...even though my tests are not completed, that they do support their customers 100% and fully stand behind their products.------------------------------------Having had a bad experience where all lens sharpness was totally destroyed using a cheaper 95mm haze with my Sigma 150-600mm, I had hopes this more expensive lens with multi-coating and higher quality glass would do the trick.It did not!Focus was perfect with and then without the filter and like my previous filter, as soon as this JONGSON filter was removed, my lens was back to stellar performance at 600mm.Will try to review forums on line and see who purchased a filter that actually will work fine with my Sigma.The degradation using this filter (like the previous one) is at 500-600mm. Given higher magnification probably maximizes the optical issues using the filter.I think one reviewer got a swap that seemed to work better, but, if this is indeed a quality control issue, (you either get a "good one" or a "bad one"), that scenario would still have me looking for another brand, hopefully a well known and trusted one!Returned it and my search will continue!

I bought this for my sigma 150-600mm lens purely to protect it. To be honest I was astounded at the price, very expensive for a protective filter but I didn't want a cheap filter on such an expensive lens.

Excellent tripod used this with my cannon 650d and a 150-600mm sigma lens on it . Very happy with it

Just received 2X UV filter for protection of my Tamron 150-600mm lens. I have had lens for many years and a very poor UV filter was previously on the lens. This new filter seems to be well made and with use of a filter removal tool should be very easy to remove if needed. Would recommend this filter.

I ordered the 52mm filter because the 30mm f1.4 sigma lens for sony e-mount cameras has a 52mm thread but after lens arrived, I couldn't fit it on.But after-service support was pretty helpful in telling me this

Solid build, just what I need to hold a 150-600mm lens firmly.

Great upgrade from the smaller one , I use it to photograph Kingfishers with my Canon 5 D mkii with a Sigma 150-600mm and it coped fine , no drooping !!! I use it more than my Gimbal now

Purchased mostly as extra protection for my Tamron 150-600mm lens. Fits fine and does what I want it to do. Good value.