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

[cynicxl]

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?

[amfoto1]

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

[cynicxl]

Oops! I meant 24-105mm L lens.

[deebatman316]

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.

[cynicxl]

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. 

[deebatman316]

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.

[cynicxl]

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. 

[deebatman316]

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.

[Anonymous]

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

[cynicxl]

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.