topic Re: help with canon 2x III extender autofocus in EF & RF Lenses

help with canon 2x III extender autofocus

ptapaskar — Thu, 24 Feb 2022 02:35:39 GMT

I have a canon 100 400 IS II USM lens and have recently purchased a canon 2x III extender.

I have a canon 6D mark II camera.

I need help/advice. on the following issues.

1. I cannot auto focus using the extender. In fact the autofocus option disappears once the lens and extender is mounted on the camera.

2. The pictures are a bit hazy.

3. Any other tips to take wildlife photos using the extender.

Thank you.

Re: help with canon 2x III extender autofocus

MikeSowsun — Thu, 24 Feb 2022 14:40:17 GMT

Your 6D Mk II can only AF if the lens aperture is f/8 or larger. Your 2x extender doubles the aperture on your lens from f/5.6 to f11 and makes AF impossible

I would advise returning the 2x and buying a 1.4x extender which will result in a f/8 aperture and still allow AF with your camera and lens.

Any extender or teleconverter will cause image degradation but the 1.4x extenders have less degradation than the 2x. Shooting stopped down at f/11 will help.

Re: help with canon 2x III extender autofocus

ebiggs1 — Thu, 24 Feb 2022 15:43:57 GMT

Always read the compatibility list before you buy a tel-con. The 2x is a bad idea even on lenses it is compatible with. IMHO, of course.

Re: help with canon 2x III extender autofocus

ebiggs1 — Thu, 24 Feb 2022 15:45:41 GMT

"Any other tips to take wildlife photos using the extender."

One of the 150-600mm super zooms. They are the best bang for the buck in a big wildlife tele. If 600mm isn't enough FL you need to get closer to your subjects.

Re: help with canon 2x III extender autofocus

ptapaskar — Fri, 25 Feb 2022 02:56:06 GMT

Thanks for your advise. This lens was in the canon compatibility chart for the extender.

Need to go for 1.4 x I guess.

Re: help with canon 2x III extender autofocus

ptapaskar — Fri, 25 Feb 2022 02:57:25 GMT

Thanks for the reply. I will exchange for a 1.4 x extender.

Re: help with canon 2x III extender autofocus

ptapaskar — Fri, 25 Feb 2022 03:00:26 GMT

Many thanks Mike.

Re: help with canon 2x III extender autofocus

ebiggs1 — Fri, 25 Feb 2022 15:28:46 GMT

"This lens was in the canon compatibility chart for the extender."

However, ....

The noted advice from Canon is, "Additionally, please see the lens and/or camera body manual for full compatibility information with the Extender EF 2X III."

Checking the 6D Mk II manual, I only see, the 1.4x III mentioned for the 100-400mm.

"EF 100–400mm f/4.5–5.6L IS II lens, with Extender EF 1.4x III."

Re: help with canon 2x III extender autofocus

alexcphotos — Thu, 11 May 2023 19:57:17 GMT

I have the same problem with that lens when shooting through the viewfinder, but what I found odd is that on my 1D-X MkII when I shoot using liveview / the backscreen, AF does work! Granted its slower to get there than the 1.4x III, but it is possible, at all focal lengths and the pictures come out sharp and in focus. I don't know how exactly the software in the camera is programmed, but if it can do it one way, why can't it the other? 🤔

Re: help with canon 2x III extender autofocus

alexcphotos — Fri, 12 May 2023 13:36:55 GMT

GIYF - found part of an answer in another thread:

"Be aware that the camera uses one AF system for when you use the viewfinder, and another AF system when you use Live View mode."

https://community.usa.canon.com/t5/EF-RF-Lenses/Canon-EF-100-400-f-4-5-6L-with-2x-extender/td-p/41075/page/3

Re: help with canon 2x III extender autofocus

wq9nsc — Thu, 11 May 2023 20:36:29 GMT

I don't use the 100-400 lens but every generation of it of which I am aware has a maximum aperture of f4.5 which puts it at f9 and outside of the f8 capability when using a 2X extender.

Rodger

Re: help with canon 2x III extender autofocus

normadel — Fri, 12 May 2023 22:27:55 GMT

You need to read the lens's manual carefully. This is what it says: