The big problem is the auto focus. I have indeed therefore bought these extension tubes, because I hate to focusing manually. Unfortunately, the AF only worked with the mitteren ring alone. Once I put another ring or even several in combination, flickered the AF and found a clear image. So taking pictures is not fun.
Another problem is the very shallow area. You have the kit lens (18-55mm) completely out and then gets in one position a sharp image. So you can not raus and zoom in to maybe to photograph a whole flower or just a section.
For this reason I have sent back the extension rings again what Amazon - has been accepted as always very accommodating and fast. 5 stars for the Amazon service !!!