A photographer friend, Dave LaHaye recently shared these two pics with me and I’m hoping to find a reason for them. When shooting portraits one day, using his Nikon D300, Dave took these two test shots–same exposures (1/250, f5), same focal length (70mm), but different lenses (18-70mm and 70-300mm). How can two different lenses, set to the same focal length, deliver such different results? What the heck? Any revelations would be appreciated!