i was renting a 2x teleconverter and i tried to mount my kit lens 18-55mm. in the booklet, it says the closest range of focusing is 0.28m. and when I mounted it, I notice a few things: 1. my AF doesn't work on f4.5 onwards 2. my f-stops is not doubled, yet the shutter speed is greatly reduced, which are basically the same issue 3. the weird yet amazing thing is the focusing reduced to 0.2m (i think) and it becomes a 110mm macro. eventhough it was manual focus. can anyone explain what happen here???