Teleconverter advise for 70-200 L USM

Hi using my Canon 70-200 1:4 L USM what would the best 1.4 Teleconverter
be for this lens,Or should I shoot for a 2.0x?

Any feedback on the Kenko brand? Or others.

Any advice appreciated,mainly shooting wildlife,birding etc...
Thanks

You have an F/4 lens. Unless you are using a 1D series, you are limited to f/5.6 for focusing- so a 1.4x is what is called for. The 1DX, though, is limited to f/5.6- I think. With a 1.4x on your f/4 lens- you will maintain the ability to autofocus.

You can use a 2.0x TC- but you might need to tape pins, or use LiveView to autofocus. You can attempt manual focusing as well.

There are lots of Kenko users on POTN from what I can tell. There are two different models - a cheaper version- and a better version- My understanding is you want the Pro series.

Well, here are the same recommendations as in the two other "what teleconverter to use with 70-200?" posts that have appeared here today.

https://photography-on-the.net …/showthread.php​?t=1207510

https://photography-on-the.net …/showthread.php​?t=1208752

1. Canon EF 1.4X II or III... either one... not much differrence optically.

2. Kenko Teleplus Pro 300 1.4X DG or DGX. The newer DGX is supposed to offer faster focusing. Not the cheaper Kenko MC4 1.4X.

3. Some folks have had good luck with Sigma and Tamron... I have no experience with those.

Any teleconverter costs light and, especially on a zoom, image quality. Technically speaking, your f4 lenses shouldn't be used with more than 1.4X, because that makes it an effective f5.6 and that's the upper limit of what your camera should be able to focus. Howerver, there are some workarounds (taping up the pins for example), or you can manually focus, though your viewfinder will be getting pretty dark by f8 effective aperture.

Due to image quality I will not use a 2X (Mark II, in my case) on my 70-200/2.8, but have recently been impressed by some images with the older lens using the latest 2X Mark III. Keep in mind that this combo is f5.6, so should AF okay (it might slow and hunt a bit). I dunno whether or not this TC would give good IQ with your f4 lens, though. It would need the workaround, though, to get AF to work at all. It definitely appears the Canon 2X Mark III works very well with the latest 70-200/2.8 Mark II.

Note: 1D series prior to 1DX, plus the older 1V and EOS-3 film cameras, can focus at f8 aperture, center AF point only. All other Canon models need f5.6 to focus (unless you trick the camera).

I just saw the other threads thanks folks.