A 10 stop group test by Bryan at The Digital Picture revealed that the Hoya ND Pro 1000 has a sharpness/ghosting issue, when the viewfinder is left uncovered. Have any of you used this filter with the viewfinder covered/block, was the sharpness/ghosting issue, still apparent ?
http://www.the-digital-picture.com/Reviews/10-Stop-Neutral-Density-Filter.aspx
http://www.the-digital-picture.com/Reviews/10-Stop-Neutral-Density-Filter.aspx