donboys

I'm not able to reply to the details but it seems CoC is dependent upon the size (diameter) of the image (i.e. sensor). But the calculation of CoC also depends on arbitrary criteria of acceptable image resolution, arbitrary being the important word. Different standards seem to exist. The purpose of these calculators is to determine the hyperfocal distance, that giving the greatest dod and extending to infinity. 

I have the Lee Seven5 system for my x100s and now x-T1.  I like the ease attaching it to the camera. One caution concerning the filter holder: the plastic filter clips are held to the holder by 4 tiny screws which go into a thin metal base with little depth. I found one screw loose in my camera bag and the small clip for the polarizer there too. Also, all four screw slots were all damaged. I was still able to replace the missing screw into its hole, including the polarizer clip, and then put lock tite on all four screws. Lee offered to replace my screws but failed to actually send them.