I wanted to find some information about DOF for my telephoto lens and that search took me to http://www.dofmaster.com/dofjs.html. I spent several several hours making myself excel charts that showed various DOF at given distances with % of distance in front of and after the focus point. This was good stuff.


Then I started looking in to my landscape lens. Landscape as a prioritesfor me comes after Wildlife and Macro. But...I did get some good landscape pictures this year and thought Ishould learn. This raised quit a few questions:


1, I have the 24mm 1.4L II and the 35mm 1.4L. I took the tripod out did some measuring and test shots what I found is that first the ft/m marks (I did properly line the F stop) did not really match up with what the real focus point would be. Also at the hyperfocal length given with the above chart (for instance at F8 for the 35mm is 16.9') much of the background landscape would be out of focus. When I moved say 4' farther back (about 21') it would come in to focus andat this distance itappeared to be the proper distance. I found the same to be true for the 24mm as well. So myquestion would be, are the charicteristics of these L lens such that the DOF charts and hyperfocal lengths do not apply or have to be adjusted?


2, The DOF chart gives near limit and far limit. Is the actual shape of the DOF of field more of a biconvex shape rather than a flat shape from one side of the frame to the other? If it is this shape is there any way to determine how thin it would be on the side of a ff camera compared to the center?