I just bought the TC-200 and paired it with my 105mm f/2.8.
If I was shooting flowers with my D5100 and 105mm f/2.8 lens at f/22 and 1/200 sec and an ISO of 200 without the teleconverter and now I add the TC-200, it doesn't show the f stop, which I did hear about, so then what f stop is it...