There are very few universal constants in photography, but one of those universal constants is the use of UV filters to protect the objective element of expensive lenses. I know of very few photographers that don't use these in one fashion or another.

I got this in 82mm, which fits my Canon 24-70 f2.8 II perfectly. The overwhelming majority of my lenses are 77mm, but I get most filters in 82mm because of my 24-70, and use 82-77mm step-down rings for most of my filters. It actually helps avoid vignetting on my 77mm lenses, anyway, so it's a good idea to step up in filter sizes if you like to "stack em deep", lol.

The quality of the filter is, frankly, excellent. I've certainly paid more for filters that weren't as good as this, so there are no complaints on quality whatsoever. The threads are smooth and well machined, and it spins on and off effortlessly.

Like most UV filters, the color shift is negligible, if it exists at all, and being high quality optical glass, I could detect no distortion in the image. The main thing it does, which is protect the objective element of my lens, it does beautifully.

As someone that has as much invested in filters as many people have invested in their entire camera setup, I'm very picky about filters. They have to be good, and if they're not good, they get tossed. This is a fantastic UV filter that is worth the cost. At around $80 for the 82mm version, it's worth every penny. Highly recommended.