The K&F Concept 62mm Magnetic MCUV Lens Protector Filter is well made and works beautifully. It's easy to use and I love the way it looks and protects my lens. It's a great product for the money.

I've been using many K&F filters in the past and I have no issue with their filter.
This one is also perfect for 49mm lens. UV filter I use is to protect the lens, and this does good job.
No image distortion has been noticed.
Highly recommend for good lens protection.

The K&F Concept 49mm MC UV Lens Protection Filter is well made and easy to use. Feels lightweight but great quality. It’s a great product.

Great price, I got it for the lens protector. The thickness is also good.

The 49mm ND filter came in a typical filter case along with three pieces of microfiber cloth.

The filter looks well made. Clear markings on the filter and so easy to rotate and set it to the desired setting. It is easy to mount the filter onto the lens and remove it. The lens cap fits over the filter just fine.

I shot quite a few images, the light gathered by the lens is reduced as the filter ring is rotated to a higher stop. Happy with the results for occasional use. I can use this filter for long exposure to get say motion blur. My initial review with some shots of the trees showing the light reduction got rejected and so not including them this time.

I used it as a lens protector for a Nikon D 5000, good fit and good value for money

Over the past year or so, I’ve tried maybe a half dozen K&F filters uniformly finding them to be among the best I’ve ever experienced. This high density ND 1000 has met my expectations of excellence that this brand has now established with me.

There’s little to say other than it’s thinner than other filters of any sort meaning it has less of a chance of creating unwanted refractions once mounted. Like all filters, it must be used alone. If added to an existing UV or clear filter many used as a lens protector, the two can and likely will work to degrade image quality. This refraction issue is a good reason not to mount the UV or clear filters as a lens protector. A lens shade works almost as well as a protector but won’t interfere with a filter.

In use, this ND 1000 does filter to 10 stops (eyeball estimate) without affecting the color or introducing other unwanted effects. Like so many things photographic, the good stuff costs but also performs.

This UV filter was a great addition to my Tamron 35mm for my Sony. This filter is definitely more of a protector than a modifier, at least in my use case, it helps protect the lens's exposed focusing mechanism and keeps dust or particles out of the lens. Overall I would say this is a great filter for any lens as it creates a barrier between the front element and the world and I have not experienced any negative effects on image quality from having this filter on the lens.