topic Re: Focusing issue with my 24-105mm L lens for Canon 5D mkiii in EF & RF Lenses

Focusing issue with my 24-105mm L lens for Canon 5D mkiii

cynicxl — Thu, 22 Jun 2023 20:56:31 GMT

My lens stays in AF regardless of whether it's in AF or MF mode, I've tried switching them back and forth and noticed that occasionally the lens does go into MF but sometimes it happens when it's in AF as well as MF mode, so it's very random.

I've tried taking off the lens a few times but nothing is working. Any tips?

Re: Focusing issue with my 18-55mm L lens for Canon 5D mkiii

amfoto1 — Thu, 22 Jun 2023 20:33:41 GMT

Please clarify...

There is no "18-55mm L" lens, let alone one that will fit onto a 5D Mark III.

There are several EF-S 18-55mm "kit" lenses (not "L" series by any stretch of the imagination). But they are only usable on Canon APS-C format cameras like 90D, 80D, 7D/7DII, T8i, T7i, T7, SL3, etc.

EF-S lenses are designed so that they won't even fit onto any of the Canon full frame models: 6D series, 5D series, 1DX series. Only EF lenses can be used on them.

So what lens do you actually have? Or do you have an 18-55mm and a different camera?

***********

Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7DII (x2), 7D(x2), EOS M5, some other cameras, various lenses & accessories
FLICKR

Re: Focusing issue with my 18-55mm L lens for Canon 5D mkiii

cynicxl — Thu, 22 Jun 2023 20:55:21 GMT

Oops! I meant 24-105mm L lens.

Re: Focusing issue with my 18-55mm L lens for Canon 5D mkiii

deebatman316 — Thu, 22 Jun 2023 21:28:17 GMT

Which EF 24-105mm F/4L IS USM lens do you have. Is this the original or the Mark II version of this lens. I've never heard of an EF lenses switching to MF when the AF/ MF switch set to AF. Does the camera still display the aperture set when this happens. If the camera displays F/-- or F/00 that means the lens IS NOT communicating with your camera.

Re: Focusing issue with my 18-55mm L lens for Canon 5D mkiii

cynicxl — Thu, 22 Jun 2023 21:33:23 GMT

I think it's the original as it came with the camera, but not 100% sure! I don't see Mark II written anywhere on the lens.

It switches randomly between AF and MF when I try switching between AF and MF but it's all very random, not always matching what the switch is assigned to. But most of the time it'll only allow me to shoot in AF regardless of whether it's in MF. The aperture seems to be fine.

Re: Focusing issue with my 18-55mm L lens for Canon 5D mkiii

deebatman316 — Thu, 22 Jun 2023 21:42:48 GMT

So your lens says EF 24-105mm F/4L IS USM is that correct. Does the camera produce an error code when this happens. If so what error code is appearing on the rear or top LCD screen. When the camera does report MF does the lens try to AF at all or not. I sounds like the AF/ MF switch on the lens maybe the cause of this.

Re: Focusing issue with my 18-55mm L lens for Canon 5D mkiii

cynicxl — Thu, 22 Jun 2023 21:50:20 GMT

Hey Demetrius. That's right! It says EF 24-105mm F/4L IS USM.
It never produces an error code, most of the time when it's in MF mode it's still auto-focusing. I keep switching between AF and MF to see if anything resets or changes, sometimes it allows me to manually focus but it can happen in either AF or MF mode, no idea what's caused this.

Re: Focusing issue with my 24-105mm L lens for Canon 5D mkiii

Anonymous — Thu, 22 Jun 2023 22:02:07 GMT

Have you tried cleaning the lens and camera contacts? You could wipe them with a clean lint-free cloth.

Re: Focusing issue with my 24-105mm L lens for Canon 5D mkiii

cynicxl — Thu, 22 Jun 2023 22:04:02 GMT

I did a quick wipe of the contacts on both the lens and the camera which didn't make a difference, but I'll give it a proper wipe tomorrow with a lint free cloth.

Re: Focusing issue with my 18-55mm L lens for Canon 5D mkiii

deebatman316 — Thu, 22 Jun 2023 22:16:30 GMT

There is an encoder switch that detects if AF or MF has been selected on the lens. This tells the camera to AF or not AF the lens when set to MF on Ring Type USM, Nano USM & STM lenses. For Micro Motor, Micro Motor USM & Arc Form Drive (AFD) lenses. This also disengages the AF motor and allows the focus ring to be turned without resistance from the AF motor. With some Ring Type USM lenses ie (EF 85mm F/1.2L), Nano USM lenses ie (EF 70-300mm F/4-5.6 II) and ALL STM lenses. These lenses have an electronic focus ring. The AF Motor is REQUIRED for manual focusing to work. Since the focus ring isn't directly connected to the lens' focusing elements.

Re: Focusing issue with my 24-105mm L lens for Canon 5D mkiii

Anonymous — Thu, 22 Jun 2023 22:23:18 GMT

You could dampen the cloth with isopropyl alcohol. Are you having this problem with another lens on this camera or only the 24-105mm?

Re: Focusing issue with my 24-105mm L lens for Canon 5D mkiii

cynicxl — Fri, 23 Jun 2023 13:27:00 GMT

Hi there,

I've now tried properly cleaning the lens and camera contacts, but the problem persists. My other lens works perfectly fine. Any ideas on what I could do?

Re: Focusing issue with my 24-105mm L lens for Canon 5D mkiii

kvbarkley — Fri, 23 Jun 2023 13:42:48 GMT

Send it to Canon for repair.

Re: Focusing issue with my 24-105mm L lens for Canon 5D mkiii

Anonymous — Fri, 23 Jun 2023 14:19:52 GMT

The problem seems to be in the lens then. It will need repair.

Re: Focusing issue with my 24-105mm L lens for Canon 5D mkiii

ebiggs1 — Fri, 23 Jun 2023 16:04:15 GMT

"I've now tried properly cleaning the lens and camera contacts, but the problem persists."

This seems to be something that new or inexperienced folks suggest all the time. It rarely to never works or even helps. And if done incorrectly it can permanently damage the contacts. The act of mounting and removing a lens is usually sufficient to keep the contacts in good working order. That's why cleaning hardly ever helps.

There is a very thin, I mean very thin, layer of gold plating on the contacts. It can easily be rubbed off. If it is, the contacts can not be repaired. They must be replaced and that ain't cheap!

You solution was given by Mr. Barkley, "Send it to Canon for repair."

Re: Focusing issue with my 24-105mm L lens for Canon 5D mkiii

amfoto1 — Fri, 23 Jun 2023 17:12:21 GMT

It makes sense that your lens is the first version EF 24-105mm f/4L IS USM, if it was provided as the "kit lens" on your camera. The 5D Mk III was intro'd in 2012 and that version of the lens was in wide use at the time. In fact, the "II" version of the lens didn't superseded it until 2016, when the 5D IV also was being introduced.

It sounds as if the lens will need to go in for repair.

But...

As this is a first version EF 24-105mm f/4L lens, it has "full time manual override" of the USM ring type focus drive. In other words, you can adjust focus manually regardless where the AF/MF switch is set. And it's mechanical (not focus by wire).

It should only autofocus when the switch is set to AF.

The problem may be in the switch itself. A little corrosion in there might prevent it from engaging or disengaging. It MIGHT help to simply operate the switch 10 or 15 or 20 times. Those switches are typically a "self cleaning" design that "wipes" away any oils or oxidization that might be on the metallic contacts inside the switch.

No guarantee this will work... But it's something you can try yourself before looking to get the lens repaired. I seem to recall a common problem with that version of the 24-105mm was a "ribbon cable" that would come loose or break wires internally, simply from the repeated flexing that occurs with normal operation. I don't know if that can cause the lens to be "stuck" in AF mode.

If you do need to get the lens repaired, contact Canon before sending it. Since that lens was discontinued around 7 years ago, they may or may not still work on it.

***********

Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7DII (x2), 7D(x2), EOS M5, some other cameras, various lenses & accessories
FLICKR