topic Re: EOS 90D & EF 100-400mm - Auto Focus doesn't work with 2x extender in EOS DSLR & Mirrorless Cameras

EOS 90D & EF 100-400mm - Auto Focus doesn't work with 2x extender

jcampbriar — Tue, 28 Nov 2023 13:38:02 GMT

I have a 90D with an EF 100-400 lens. When I put on my 2X extender the autofocus doesn't work at all. Is there some setting I need to change?

Re: Auto Focus doesn't work with 2x extender

Waddizzle — Sun, 26 Nov 2023 00:39:34 GMT

That is normal behavior for that specific combination of camera body, lens, and extender. Please refer to the”90D Supplemenatl Information” guide for a detailed explanation.

https://gdlp01.c-wss.com/gds/8/0300036248/02/eos90d-si2-en.pdf

Re: Auto Focus doesn't work with 2x extender

Peter — Sun, 26 Nov 2023 07:43:30 GMT

As a workaround you can enable Live view.

Re: Auto Focus doesn't work with 2x extender

Waddizzle — Sun, 26 Nov 2023 12:02:52 GMT

@Peter wrote:
As a workaround you can enable Live view.

I’m just a little surprised the camera does not produce an error message. The camera/lens combo is not listed to work with any version of the 2.0x. That’s usual result when you try to use unlisted combinations.

Re: Auto Focus doesn't work with 2x extender

Waddizzle — Sun, 26 Nov 2023 12:05:36 GMT

I apoligize for telling you to read the manual. But this is not a simple topic to discuss. You need to be able to “speak the language”, if you will. If you have any questions, just ask.

Re: Auto Focus doesn't work with 2x extender

Peter — Sun, 26 Nov 2023 13:43:21 GMT

Had success with 6D +100-400 +x2III in Live view.

Re: Auto Focus doesn't work with 2x extender

Waddizzle — Sun, 26 Nov 2023 14:02:48 GMT

@Peter wrote:
Had success with 6D +100-400 +x2III in Live view.

Interesting. I don’t even get that far. Error message on power up with that body and the 6D2.

No idea what firmware is in the cameras. I think the last firmware update I did was the security update for the USB port a couple of years ago,

Re: Auto Focus doesn't work with 2x extender

jcampbriar — Sun, 26 Nov 2023 16:42:41 GMT

Thanks for the feedback. At least if wasn't something I was doing.

Re: Auto Focus doesn't work with 2x extender

johnrmoyer — Mon, 27 Nov 2023 13:14:47 GMT

In live view, my EOS 80D does DPAF like a mirrorless camera so with enough light it will even autofocus at F/13. I would guess that the EOS 90D does even better.

I find live view awkward for hand held shots with the EOS 80D and did not use it much.

The lens and extender should work fine with auto focus in live view when there is enough light.

Here is an auto focus example using an unsupported combination at F/11 on EOS 80D where auto focus worked: https://www.rsok.com/~jrm/2017Feb07_birds_and_cats/2017feb01_cardinal_IMG_0929.html

Re: Auto Focus doesn't work with 2x extender

elmo — Tue, 28 Nov 2023 00:00:32 GMT

I have this issue with my R8 and RF100-500 with the RF2x. I enabled using the manual focus ring in the settings even when in AF. Once I have my subject in focus manually, AF seems to work fine afterwards (like on a moon shot).

Re: EOS 90D & EF 100-400mm - Auto Focus doesn't work with 2x extender

normadel — Tue, 28 Nov 2023 21:46:25 GMT

This IS a simple matter to discuss. The manual for this lens very clearly states that AF does not work with extenders 1.4X or 2X. Manual Focus must be used.

See for yourself, on page 17.....

https://gdlp01.c-wss.com/gds/6/0300017486/01/ef100-400f45-56lisiiusm-im-e.pdf

You really have to consult the manual for a lens to see if it is functional, and how, with extenders. Some lenses forbid it entirely, or AF won't work with aperture smaller than f/8, etc.

Re: EOS 90D & EF 100-400mm - Auto Focus doesn't work with 2x extender

johnrmoyer — Tue, 28 Nov 2023 22:28:07 GMT

For any camera that has DPAF in live view, then the autofocus will work in live view no matter what F number so long as there is enough contrast and enough light. But you are correct that autofocus will not work when using the viewfinder. Also, bright light and strong contrast is needed. The manual also says auto focus for my EOS 80D will not work at F/11, but that is referring to when the viewfinder is used. Many things work that the manual says will not, but they do not work in all circumstances. A Canon extender will not work with this EF70-300mm f/4-5.6 IS II USM lens because there is not enough space behind the last lens element, but this particular Kenko teleconverter does work. Also the Canon 2x III with the 100-400 will work.

Autofocused in live view at F/11 with a combination of lens and 2x extender that the manual says will not work, 600 mm , Canon EF70-300mm f/4-5.6 IS II USM, Kenko Teleplus HD C-AF 2X DGX teleconverter