“I have had very good results with K&f service and products. I have updated my 20-30 year old filters to the Nano k series, after reading reviews. I just ordered 3 of their Nano x series to see if there is any difference in picture quality with my Zuiko 100mm-400mm lens on an Olympus OM-D E-M1 mark iii camera. I will update after this after I receive the filters”
