2 x extender autofocus

[BryanShaw1]

I have just purchased a used Canon 2 x extender II.

When fitted to my 7D, the Q screen automatically changes to MF MANUAL FOCUS.

Is the extender faulty?

[Waddizzle]

---

@CaliforniaDream wrote:

This use to be true, But not anymore!

---

@Waddizzle wrote:
No, it is not faulty. The 2x extenders do not work with, or allow for autofocus, with any and all combinations of cameras and lenses.

---

---

It still holds true for the OP's EOS 7D DSLR camera.

[CaliforniaDream]

Absolutly correct

[ebiggs1]

John Hoffman's unofficial samples proves that a native lens can and does produce similar results, perhaps even a bit better, when cropped to tel-con status as the addition of the tel-con on the lens.  So why bother?

[lesstuna]

So I have also now come across this problem with the 2X Converter. I have Canon EOS 6D Mark II, Canon EF 100-400mm f/4.5-5.6 L IS II USM Lens, and have both the Extender EF 1.4X III and the Extender EF 2X III. I have had no problems at all with the AF using any of the above combinations up until today.

I was shooting with just the 100-400 lens, and wanted closer so I put on the 2X Extender, for the first time ever, the auto focus will not work, it has been working fine since January when I bought the extender, and now no matter what I try, it stays in manual focus.

Anyone have any ideas? I think maybe I put the Extender on the camera by accident without the lens attached, and then before doing anything, fixed that, and attached the extender to the lens and then to the camera. The AF has not worked since.

Any solutions? Maybe reset the camera to factory default maybe? The 1.4 Extender works fine, the lens alone works fine, as does my 24-105 lens. Just the 2X III will no longer AF

[jrhoffman75]

 Are you sure it ever focused? The 6D Mark II has an f/8 aperture limit for AF, same as my 1D X Mark III, which does not AF with the 2X TC. The 100-400 f/4.5-5.6 would have an f/9 equivalent at 100mm with the 2X TC.

[lesstuna]

It has worked perfectly since January, autofocus was not an issue until today.

[BryanShaw1]

As the originator of this thread, I gave up with the 7D and bought an R with which the 2x AF works a treat!

I'm really impressed with this camera which was the only mirrorless I could afford. I'd love to try the R5 to see how much better it performs and would be interested to hear if anyone out there has made this comparison.

[lesstuna]

Not sure what to say about all of that, but the auto focus has been working with the 2X III for 3 months. Oddly enough, I just put the 2X III back on the 100-400 and the auto focus is working again. No question it is working, I just put the camera completely out of focus with the manual ring, and a couple of 1/2 presses of the shutter and bang, focused. I did understand when I bought the 2X III that it would "slow down" the auto focus due to losing the 2 stops, so it would not be good for panning or following a moving target, but it does work for distant still targets. Anyway, it is working again and I have no explanation why it stopped or started working again.

[jrhoffman75]

What focal length is your lens at when it focuses with the 2X?

[lesstuna]

I do not see any way to attach an image here, but it works within the entire range of the 100-400 so 200-800. I have many sharp images at 800 mm equivalent using the auto focus, the CN Tower here in Toronto is 5 miles away, and lots of lunar shots at night, etc. Could it be because of the 2X III newer version or software updates or something? All of this stuff is relatively new, the 6D and 100-400 was last June so 9 months old, and I got the 2XIII in January so 2 1/2 months of using it with the 100-400. All firmware updates were done on everything I have.

The last image I took of the tower on 2022-03-20 the camera details in the properties is f/11, 1/80 sec, ISO-200, 800 mm, and that image is very sharp for 5 miles away.