topic Re: EF 28-105 AF not working in EF & RF Lenses

EF 28-105 AF not working

Markussqw — Sat, 01 Feb 2025 09:39:36 GMT

Hello! I have an EF 28-105 f/3.5-5.6 lens (USM motor) and I have AF problems with it. the autofocus does not work, I hear a few clicks while focusing (very softly), and the focus ring is difficult to move. I have another USM lens, but the ring on this one is very difficult to move.

Re: EF 28-105 AF not working

Waddizzle — Sat, 01 Feb 2025 17:46:58 GMT

Sounds like there’s some sort of issue. I don’t think the lens is still being repaired by Canon.

Re: EF 28-105 AF not working

Markussqw — Sat, 01 Feb 2025 19:02:04 GMT

Could it be that the lens is very dusty inside?

Re: EF 28-105 AF not working

Markussqw — Sat, 01 Feb 2025 19:02:46 GMT

Here is a picture

Re: EF 28-105 AF not working

Ron888 — Sun, 02 Feb 2025 04:54:22 GMT

I dont think the dust is affecting the focus motor.More likely its broken somewhere inside

Re: EF 28-105 AF not working

Markussqw — Sun, 02 Feb 2025 06:11:36 GMT

Ok, i dont want to replace the USM motor. I buy a new lens

Re: EF 28-105 AF not working

deebatman316 — Sun, 02 Feb 2025 13:47:20 GMT

Do either of those lenses have a focus distance window on them. If they don’t they use the cheaper Micro Motor USM. These lenses DO NOT support Manual Focus override while in AF mode. So don’t attempt to turn the focus ring in AF Mode. Only the EF 50mm F/1.4 USM lens supports it. It has an additional clutch system to support this. It is also the only Micro Motor USM to support it.

Re: EF 28-105 AF not working

Markussqw — Sun, 02 Feb 2025 14:36:50 GMT

But this lens has a focus distance window

Re: EF 28-105 AF not working

deebatman316 — Sun, 02 Feb 2025 14:42:41 GMT

Something is broken in the lens. Time to look for a new lens. It’s also not serviceable by Canon anymore. Time to look for a new lens.

Re: EF 28-105 AF not working

Markussqw — Sun, 02 Feb 2025 14:44:26 GMT

What's the best RF alternative for 400$?

Re: EF 28-105 AF not working

deebatman316 — Sun, 02 Feb 2025 14:52:50 GMT

The RF 24-105mm F/4-7.1 IS STM lens or RF 24-50mm F/4.5-6.3 IS STM lens.

Re: EF 28-105 AF not working

Markussqw — Sun, 02 Feb 2025 14:54:44 GMT

Thanks, i buy an RF 24-105 f/4-7.1 IS STM

Re: EF 28-105 AF not working

deebatman316 — Sun, 02 Feb 2025 14:56:03 GMT

Also what camera do you have. Please provide the Full Model Name. You mentioned a Full Frame EF Mount lens. I want to make sure that you do indeed have a Full Frame RF Mount camera. RF lenses aren’t compatible with EF Mount cameras.

Re: EF 28-105 AF not working

Markussqw — Sun, 02 Feb 2025 16:12:23 GMT

I have a Canon EOS R100

Re: EF 28-105 AF not working

deebatman316 — Sun, 02 Feb 2025 16:15:33 GMT

Then look into the RF-S 18-45mm F/4-6.3 IS STM it’s specifically designed for the smaller sized APS-C image sensor size.

Re: EF 28-105 AF not working

Markussqw — Sun, 02 Feb 2025 17:29:01 GMT

I have one of these lens. I buyed in a kit

Re: EF 28-105 AF not working

deebatman316 — Sun, 02 Feb 2025 17:40:57 GMT

So are you looking into a telephoto lens then. The 24-105mm is a standard zoom lens for a Full Frame camera and it wouldn't provide an ideal focal length for an APS-C camera. But it would still work but It would be difficult to use. Have you thought about the RF-S 18-150mm F/3.5-6.3 IS STM lens or the RF-S 55-210mm F/5-7.1 IS STM lens. Its on sale refurbished for $279 on Canon's online store.