In this post I would like to share my personal experience with Lee Big Stopper ND filter, rather that provide full technical review, which you might be used to from other websites. I have been experimenting with Long Exposure techniques for couple of years.   I started with just three EV stop full ND filter, which allowed me to get exposures in range from 1 to 30 seconds during the day. Latter on I become quite curios what the photographs can look like with longer exposures and I purchased ten stop round ND filter with the tread to attach to my lenses.