Thank you , must admit I'm really enjoying using this little lens . Unfortunately my TC-17e doesn't work too good with my 300mm PF , IQ takes a huge hit compared to using the TC-14e iii , maybe it's a bad copy although it does work well with my 300mm f2.8 after stopping down . The only downside with the PF is that far away objects don't look too great , the bigger f2.8 with or without TCs is much better .