The tone seems kind of flat, that's what I observed, possibly because it cuts out glare and reflection and affects the skin tone...I am sure there are some scientific explanation to this. Similarly using grad filter will cause problem if the upper body is in the darker tinted area. So possibly a full ND filter works best.....am using a Singhray vari-ND whenever I need to open up my F-stop of use a slower shutter speed. There are cheaper alternative now than Singhray at fraction of what i pay for it...but not sure about the quality.