In the prior post I showed how setting this lens' focus ring at 12 feet was all you needed to do if your subject is between 6 feet and infinity. And even that superb depth of field assumed setting aperture at F2.0. The DOF only gets greater as you stop down. At F11 when focused at 12 feet, DOF is a whopping 2 feet to infinity.
Above is a shot I took while having a cup of coffee this morning. F11 with focus set at 12 feet. The coffee mug is about 2 feet away from the sensor plane and about 18" from the front lens element.
The tippy top of a spruce tree is in the middle of the frame, and is pretty much to farthest point of the scene. I think it looks reasonably sharp (see 100% crop below); nevertheless, I believe that the sharpest images with this lens are at F4, F5.6 and F8. But since one characteristic of an ultra wide angle lens is that it emphasizes the foreground (in this case, the coffee mug), I am wondering how sharp the distance background really needs to be. In the field I don't think I will fear F11.
|100% crop from the center of the image.|
tip top of the center spruce tree looks reasonably sharp to me.
F11 with focus ring set at 12 feet. DOF= 6 feet to infinity.