Also, don’t forget masking by painting (not just an outline created with a tool) - if parts of the object are out of focus, and you want to keep that rather than a hard edge, then you will be using a combination of anything from the Pen Tool, to the Lasso, and Masking.
If you have the back of the shoes out of focus, yet is has a hard edge in the cutout, it can look funny. If it is going to be printed small - say, 2 inches or smaller - than it won’t really matter. But if it’s going to be big where you can see changes in focus - well, you get the idea.
Hope this helps-
-Lew