I just received this lens I "won" on ebay to enlarge my 6X6 negatives.I wanted a faster lens than 5.6 but at $30 including shipping I couldn't pass it up. It is a beautiful well build lens. I know that most enlarging lenses are best stopped down at least a stop but if I have to use this lens wide open how is the performance for an 8"X10" or an 11"X14" enlargement? I would tend to think this lens would be good wide open because fully opened I can see the blades coming in a little at the edge maybe about 15 percent or so, as if they could of made this an f4 lens if they wanted to. Hope this makes sense.