37mm Camera Lens Filter Set Circular Polarizer Lens Filter with Adapter Ring and Protective Fit for Xiaomi 4k/4k+/Lite...

When I took it out of the packaging and first put it on my camera my first thoughts were hmmm, thats not as snug as I thought it would be, but that will work. On the inside of the cover is a rubber strip that goes around the inside. This is supposed to provide the snug fit to keep it on the camera lens. It does a good enough job of that, for about a minute. Once it has been on the camera and moved around a bit the cover becomes very loose. Be careful not to look at it from across the room, it might fall right off the camera. Total waste of money and time. The rubber compression ring needs to be a little thicker and/or sticker. Id have posted a video but apparently Ive left it somewhere not caring if I ever saw it again. Also, the bit I did have it on my camera I believe it was making contact with the camera lens. It left a spot on the crown of my lens. I was able to rub that out with a pre-moistened lens cleaning towelette.

The adapter ring is made of aluminum, with similar workmanship to "real" camera lenses. The foam is just right to hold it on, but the slight taper on the camera means that it isn't really secure enough to bounce around in a pocket. The circular polarizer seems to be of normal lens quality, and spins smoothly on lens oil. Four stars from me because I was hoping to sometimes use this with just the lens cap (no CPL) to protect the camera when outside its waterproof case, but the lens bulges out enough to touch the back of the lens cap (it doesn't touch the CPL because of the extra height for the rotation ring). Not sure if it will clear other 37mm filters, like UV or ND. This isn't really a ding, just a minor disappointment and a route for improvement.

I did not intend to write a review actually. I was on ZeeBooth to order a second lens set assembly for my second Yi camera. I own a Yi Lite and a Yi 4K+ as well as the Yi handheld Gimbal 2. This assembly easily fits on each camera without any interferences to the Yi gimbal The high points: The unit slips very securely over the lens barrel of the Yi cameras with no fear of any looseness. The coating on the Circular Polarizer appears to be of very high quality. I own Leitz and Zeiss binoculars, Vixen refractors, Canon L lenses, and more. Optically and mechanically, the supplied filter is quality, and not junk. I have the Yi gimbal and the lens assembly fits perfectly over the Yi lens barrel without any interference with the gimbal bracket. The lens cap itself uses side tabs which are pressed to release the lens. It is very secure with minimal chance to pop off. The Low Points: None really. You can see that I placed a piece of blue tape on the cap to help me quickly orient where I need to press the tabs. Other manufacturers don't mark them either so this is not a negative. Indeed some users may find such a piece of tape unaesthetic. Pros use tape all the time on camera gear. This is a definitely buy recommendation. I have ordered a second one, with CPL filter. I'll probably order a third, as well as additional ND filters, and maybe a warm soft filter in a 37mm Diameter size later down the road. Five stars from a user who has shot everything from Canon 1014 Super 8mm to the latest 2018/19 technology. I only hope that any new Yi action cameras in the future will be compatible. If not, the price of these units is easy on the pocket book for almost everyone.