Hi there, I purchased a Sigma - 24-70mm 2.8 lens.... I hear that the Sigmas have good batches and bad batches... blah blah blah. My images seem to NEVER be sharp. I tryed all the advice that I get here. (kids -- use F11 with a faster shutter speed) Heres the stupid question part.... How can I test the lens for sharpness?-- Besides stating the obvious... take a picture and see if its sharp..obvious... I'm really embarrased about this question.. BUT I dont know who else to ask? Mods - If this idiotic question needs to be moved to beginners feel free.. I had no idea where to post.