Excerpt: Just Trying out my new Kenko 2x TELEPLUS PRO 300 with my Canon 2.8 L 70-200mm lens. Took this photo while sitting at my dining room table through a dirty screen and window, not too bad so far, very easy to use and so happy to get the extra focal length and such a bargain price compared to the Canon counterpart.
Pros: Compact, Easy to Use, Great Picture Quality, Lightweight
Excerpt: It is a 2x extender and as a result you do lose 2 stops of light. as a result of that you lost AF using the built in sensors. However, AF still works in bright light and if you shoot with the shutter up (Screen) and not the view finder (Uses the CMOS sensor vs phase detection).I sent it back because it just was not what I wanted but I still think it is a good product for the price.
Summary: I use this on my Nikon D7000 and a 18-300mm VR Zoom. The autofocus is totally unworkable under any lighting condition even bright summer sun light. The image can never get focus with autofocus. I can only use manual focus. The image was soft.
Summary: When mated to my 6D and 70-200 2.8, there is some play between both the body-converter and convert-lens. I do not have this play when the lens is mated directly to the body. Has anyone else experienced this? I haven't had enough time with the converter to review the quality of the pictures but it appear acceptable so far.