I don't use this lens that much anymore. For my travel purposes, I like the smaller and of course, lighter the f/4.0 version of this lens. On a few occasions I felt like I want to sell this lens but each time I think of that, I took it out and use it. Each time, I came back and told myself not to do that. This lens delivers at even full aperture. Focus on the eye of the flamingo eye and take a look at the next image of the same shot but enlarged at 100% crop.