Super Stopper Practice

I've had the Lee Super Stopper (a 15 stop neutral density filter) for ages, but can't remember using it for a blip.  To give you an idea, if my shutter speed was 1/125th of a second, putting the filter on the lens would result in a 4 minute exposure at 100 iso.  On a windy day, I thought it would be interesting to see the effect.

I'd have preferred a few more clouds, but I think you can get an idea of the effect.  I tried a few shots with my 14-30 mm lens, but found a large amount of vignetting occurring in the resultant image which had to be adjusted in post processing.

Day Miles:  5.0 miles. Total Miles: 861.0 miles