topic Canon RF100-500mm MF stopped working in EF & RF Lenses

Canon RF100-500mm MF stopped working

Cazthecat21 — Mon, 20 Oct 2025 19:57:04 GMT

Hi, MF isn’t working on my RF100-500mm (on an R8. As I twist the focus ring the scale doesn’t move on the LCD. Don’t think I’ve altered any settings. Be grateful for any suggestions, thanks.

Re: Canon RF100-500mm MF stopped working

March411 — Tue, 21 Oct 2025 00:15:46 GMT

I believe by default the focus ring may not work when the camera is set to autofocus (AF) modes like One-Shot or Servo AF. To resolve the challenge, turn on the lens electronic manual focus setting in the AF menu.

You can also set up a custom button to enable manual focus override which works well when AF wrestles with achieving focus.

Be aware that the focus ring is still overlooked when the camera is in Servo AF mode since Servo is intended to constantly track the subject.

If this information doesn't help you may want to reach out to Canon support @ 800-652-2666

Re: Canon RF100-500mm MF stopped working

p4pictures — Tue, 21 Oct 2025 07:38:29 GMT

To be able to manually focus an RF lens, you need to select manual focus, and in the case of the RF 100-500mm that is primarily controlled from the AF/MF switch on the lens.

If the switch is in the AF position, there are menu settings in the camera that will allow electronic manual focus to be used with RF lenses and EF lenses with electronic focus rings. Look through your camera AF menus, and locate the setting for Electronic full-time MF, and enable it. Then as long as you are not activating AF with any button, and you have Preview AF disabled, you will be able to turn the focus ring on your RF 100-500mm to focus it manually.

Electronic full-time MF has priority over the Lens electronic MF setting.

https://cam.start.canon/en/C013/manual/html/UG-05_AF-Drive_0110.html#AF-Drive_0110_3-1

Re: Canon RF100-500mm MF stopped working

Cazthecat21 — Tue, 21 Oct 2025 18:18:50 GMT

Thanks for getting back to me. Maybe I wasn’t clear but the focus ring was moving before, back and forth along the scale. So I’m wondering if it has developed a fault?

Re: Canon RF100-500mm MF stopped working

Anonymous — Tue, 28 Oct 2025 13:07:16 GMT

If you've set the lens switch to AF being able to MF depends on these settings

Re: Canon RF100-500mm MF stopped working

favesa8061 — Fri, 14 Nov 2025 05:06:33 GMT

Hello,

That's a frustrating hiccup, especially with a professional lens like the Canon RF 100-500mm and the Canon R8! When the focus distance scale doesn't appear or move on the LCD while you're twisting the manual focus (MF) ring, it usually indicates a setting has been inadvertently changed or a specific feature e-zpassde is overriding the display.