Breakthrough X4 77mm ND64 Filter Review - Part 1

Breakthrough X4 77mm ND Filter Review - Part One.There’s more to life than looks of course but it is difficult to avoid forming a first impression. From the moment I opened the box, this filter created two impressions. It looked like a high end piece of engineering and it stood apart from the crowd. Such an attention to detail by a manufacturer sends an instant message. ‘We know what we’re doing and we believe it is important to do it right’. As soon as the box is opened two practical aspects make themselves known. After countless years, a manufacturer has finally included a sufficiently 'grippable' edge to transform the process of mounting and removing. At best we’ve been given a knurled edge or often a smooth edge with a lightly knurled front. The X4 starts from a more functional approach and gives an edge that is more scalloped than knurled and provides an infinitely better grip. Even with gloves this is a breeze to remove and no more need for filter removal tools for overtightened items. Secondly, although in principle  the engineering of threads is relatively straightforward, there is a world of difference between the individual variations of a so called standard pitch. Some are simply cut to poor tolerances, others while accurate are left with edges sharp enough to cut skin. Poorly cut threads are a potentially expensive accident waiting to happen. From the moment you first offer up a filter you know instantly how good the thread is, some fight and others work with you. The Breakthrough, almost threads itself. The frame is CNC machined from Brass and oozes quality. The same attention to detail is also paid to the glass, Schott B270 in this case. Secondly a 16 layer multi coating is applied ( 8 layer to each face)  and finally a nano coating which both serves to bead water droplets and make it easier to clean off any marks.Optical performanceBreakthrough make a number of significant claims for the filters including a completely neutral colour, class leading sharpness and great resistance to marks and moisture.Colour: It is certainly the most neutral 6 stop filter that I’ve ever used. In my view, the sample I have, is not quite completely neutral, there is a very, very slight blue cast. Nothing however that cannot easily be removed. Sharpness: I cannot fault the optical sharpness of the filter, more attention will be paid to this is part 2 but for now, it seems flawless.Finally the Nano coating succeeds in two ways. After multiple days in the field, the filter remains unmarked. In light rain the filter resists the water and drips quickly bead and run off. This is a high end product at a high end price but it is easy to see what value has been added. There is a certain pleasure to be derived from anything that is done well and this is a beautiful piece of engineering. Unique in my experience is the presence of an individual serial number for each filter. This enables the similarly unique offer of a 25 year guarantee to be claimed. Although a full comparison with other industry leaders will form the basis of the second part of the review, I currently would have no reason not to make this my first choice for a screw in ND64 filter.