Review on K&F Concept 77mm ND8 (3-Stop Fixed Neutral Density Filter) ND Lens Filter - Premium 28-Coating HD Hydrophobic Ultra Slim Nano-X Series Filter for Camera Lens by Kevin Johnson

I have a Canon 85mm f/1.4 and on a sunny day it's not always possible to shoot fully open without stuttering. The presence of an ND8 filter that cuts incoming light by 3 stops is almost perfect for you to open the widest aperture and shoot. In my picture above you can see the glass is pretty good for this. Ignore the focus (since the left photo was taken at f/4, the right at f/4), I can't tell a difference in image sharpness in my other shots, even looking at the pixels. The two images were taken with my aperture 3 stops apart and you can see that the overall brightness is about the same (note the f/1.4 vignettes due to my lens) - so this is a true ND8 filter. . There's a slight color cast, but it's very minimal and Photoshop automatically adjusts it anyway when you start editing your images. Threaded on the front if you need to install another filter. If this review ended here I would give it 5 stars. Unfortunately, the thread for attaching this filter to the lens is deformed or poorly threaded. I've spent a good 2 minutes on it each time (turning back until it looked like it would fall off, then tightening etc) and it kept trying to cross the thread. When I thought I leveled it it was pretty tight to turn and I don't know if I even got a full turn out. I figured maybe I'm just bad at filter threads so I grabbed my black and white filter (brass thread) - 5 seconds, straight, fully on, no problem. So, I grabbed my Hoya filter (aluminum threaded) - 5 seconds, straight, screwed it all the way in, no problem. The problem was not with me and not with my lens, but with this filter. Maybe 2 stars is a bit harsh, but when you're mounting it on the front of a $2,000 lens, the last thing you want to worry about is cross-threading, damaging the lens, or worrying about it coming off as a result not fully engage in the thread. The glass on this filter is of the highest quality, but I wish they would take the same care and make filament of the same quality.