EF 24-105mm f/3.5-5.6 IS STM Won't Focus on EOS Film Camera

[Filmfan]

Hello, I have a film camera: Canon EOS Rebel Gii and I recently bought a Canon EF 24-105mm f/3.5-5.6 IS STM lens to go with it. I did a lot of research about which lenses are compatible, and all stated that EF lenses would work. However, the lens won't focus manually or automatically unless I first connect the original lens it came with, autofocus it, take it off, then put the Canon EF 24-105mm f/3.5-5.6 IS STM lens on. If I turn the camera off, then I have to go through the whole process again and it is quite a cumbersome. Plus I don't want to carry around my old lens everywhere just for this purpose. I was wondering if anyone has run into this issue before? Is it because it's a STM model? 

[deebatman316]

No it should work the same as an EOS Digital camera. Manual Focus Override does work while in AF Mode with that camera. What camera did you try the lens with. Was it a DSLR camera or a film body. 

Correction: Yes it does work like any other EOS Film body or EOS DSLR camera. The restriction was for early Rebel Film camera models. Your camera has no such restrictions.

[Filmfan]

It was a higher end digital body; I'm not sure which one though because an employee tried it at a camera store quickly just to see if it works with other cameras and I didn't see what body he used. 

[deebatman316]

The more recent Rebel/ XXXXD/ XXXD do support Manual Focus Override while in AF. All of Canon's current cameras do regardless of the model. It was very old low end film rebels and very old lower end digital bodies that had restrictions. Those restrictions don't apply to your camera. Do you have or know anyone with an EOS DSLR camera try it on that one. To see if it works on that one. If it does post the model name of that camera.

[ebiggs1]

Filmfam it could be as simply as a weak battery. It could also be a faulty battery charger. I generally say to never clean the contacts as it is almost to never a contact problem but on this old camera it might be wise. You need to use a qtip with just a drop or two of alcohol. Wet yes, dripping no. A dry microfiber cloth will do nothing if they are indeed dirty or contaminated.

[Filmfan]

The battery is fairly new and it still shows full battery on the camera. I also just cleaned the mirror box and it still doesn't work. I think the weirdest part of this all is that it works after I connect the original lens first and autofocus on that. Then if I plug in the new lens, it autofocuses perfectly. This suggests there is something faulty with the initial connection to the STM but once it's overcome then it works just fine.  

[ebiggs1]

Oh, BTW, was the lens new or used?  If new don't clean its contacts.

[ebiggs1]

I have never heard of a STM lens needing a jump start. I gather this is a used lens? I hope for you that you can return it. It does sound like it is misbehaving. Every EOS camera is compatible with every EF lens ever produced.

[deebatman316]

The OP reported that the lens worked correctly on a high end DSLR camera. It could be weak batteries or dirty lens contacts. Removing and Reattaching the lens could be re-establishing proper lens and camera communication. If the camera contacts are dirty. But this is rarely the case but its possible. Removing and reattaching lenses should be sufficient enough to keep the lens contacts clean.

[MikeSowsun]

STM lenses should be fully compatible with the Canon Rebel GII. (also known as EOS 3000N and Rebel XS N) I suspect there must be a problem with the camera. Even the early “focus-by-wire” USM lenses should work. Many of the advanced film cameras had a Custom Function for “focus by wire” lenses. But the “Manual focusing with the electronic manual focusing ring” Custom function, was only designed to disable manual focus override with “focus by wire” lenses. 

This is from the EOS 1N user manual:

“This option disables the manual focusing capability of the electronic ring pro- vided on many USM lenses, eliminating the possibility of accidentally turning the ring and shifting the focus after autofo- cusing is completed.”

Compatible Lenses

• EF 50/1.0L USM
  EF 200/1.8L USM
  EF 400/2.8L USM
  EF 600/4L USM
  EF 28-80/2.8-4L USM
  EF 85/1.2L USM EF 300/2.8L USM EF 500/4.5L USM EF 1200/5.6L USM

[deebatman316]

I tried the specific lens in question and also the EF 50mm F/1.8 STM lens on 4 EOS film bodies. The EOS 650 (1987, first EOS camera), EOS-3 (1998), EOS-1V (2000) & EOS Elan 7NE (2004, last EOS film body). All of which lenses functioned correctly and had no problems. Including Manual Focus Override. Manual Focus Override doesn't work in AI Servo it ONLY works in One Shot. That's the only restriction that I can find. It would also make sense why it doesn't work in AI Servo. The lens is focusing continuously so you can't fight the AF Motor.