EF 16-35 II on R6

[enriquehoja]

Hi all,

I recently acquired this EF lens, the II version secondhand and have noticed that unlike the RF 15-35 I tried, no focus scale is indicated in the EV or LCD and that with manual focus the ring does not stop at either end (zero or infinity). Are these issues to be expected? Thanks

[enriquehoja]

Thanks to everyone answering here. This is the first time I have used an EF USM lens, so now I know 🙂

[deebatman316]

Actually this is NOT true for Canon's EF 16-35mm lenses. They have focus rings mechanically connected to the focus elements. Almost ALL Ring Type USM lenses provide mechanical AF override. Some of Canon's early Ring Type USM lenses are focus by wire like STM lenses. The Canon EF 85mm F/1.2L II USM was Canon's last focus by wire Ring Type USM lens. ALL RF Mount lenses use electronic focus rings whether STM or USM.

-Demetrius

Current Gear: EOS 5D Mark IV, EF 16-35mm F/2.8L III USM, EF 24-70mm F/2.8L II USM, EF 50 F/1.8 STM, EF 85mm F/1.8 USM, EF 70-200mm F/2.8L IS III USM, 470EX-AI & 600EX II-RT

Retired Gear: EOS 40D & Sigma 17-50mm F/2.8 EX DC OS HSM

[deebatman316]

Note some EF USM lenses use an electronic focus ring. In order to manually focus you must half press the  shutter button and turn the focus ring. Manual focus will NOT work if the shutter button isn't pressed half way regardless if the AF/MF switch is set to MF. This also applies to EF STM lenses too. This doesn't apply for the 16-35mm because the focus ring is mechanically connected to the focus elements.

-Demetrius

Current Gear: EOS 5D Mark IV, EF 16-35mm F/2.8L III USM, EF 24-70mm F/2.8L II USM, EF 50 F/1.8 STM, EF 85mm F/1.8 USM, EF 70-200mm F/2.8L IS III USM, 470EX-AI & 600EX II-RT

Retired Gear: EOS 40D & Sigma 17-50mm F/2.8 EX DC OS HSM

[JoeySnaps]

Glad to get authoritative information, thanks Demetrius for putting me right.

Can I ask some clarification information, then? I think I did know that EF USM lenses had a mechanical focus linkage, I'd just forgotten. Am I right that you can check this by rotating the focus ring when the lens is not powered up - if the focus mechanism moves there's a mechanical linkage, if not then it's focus by wire?

Secondly, if there's a mechanical linkage between the focus ring and the internal focusing mechanism, why doesn't the ring stop at the infinity and closest focus positions? Is there a clutch that disengages at these points, as you describe for the EF 50mm?

Thirdly, when you state that all RF lenses use electronic focus rings, is that the same as focus by wire? All my lenses are now RF (except I still have an EF 40mm pancake lens, which is STM and I know that's focus by wire).

Forgive me for hijacking this thread, I'm just always hungry for more knowledge about this sort of stuff.

[deebatman316]

1. Yes if the USM lens has a mechanical focus ring the distance scale will turn as you turn the focus ring. Even if the lens isn't mounted to the camera or the camera is turned off.
2. Yes. But this clutch prevents you from turning past the focus extremes. The ring will continue to move. Also this clutch stops the focus ring from turning when the AF motor is in use. All Ring Type USM lenses that have a mechanical focus ring use a clutch for AF override. The EF 50mm F/1.4 USM is the ONLY Micro Motor USM lens that supports MF override while in AF Mode.
3. Electronic Manual Focus/ Electronic Focus ring are the same thing as Focus By Wire.
4. Note STM lenses DO NOT have a focus distance indicator on the lens. ONLY Ring Type USM have this. Except the EF 50mm F/1.4 USM lens as discussed already for its Focus ring set up.
5. Micro Motor USM lenses also DO NOT have a Focus distance indicator. The focus ring will TURN when AF is being performed. IF you attempt to turn the focus ring while the AF/ MF switch is set to AF. The focus ring WILL BE HARD TO TURN. Micro Motor USM lenses will turn the focus ring while AF is being performed.
6. Early Ring Type USM lenses such as the EF 50mm F/1.0 USM, EF 85mm F/1.2L I/ II USM, EF 300mm F/2.8L USM. Use focus by wire all early telephoto and super telephoto lenses use this system. 
7. Nano USM lenses such as the EF 70-300mm F/4-5.6 II USM, EF-S 18-135mm IS USM lenses. Also are focus by wire lenses. These lenses will NOT manually focus if not mounted to a camera or if the camera is turned off.
8. The first EF lenses released in the 80s without USM AF motors used AFD (Arc Form Drive/ Auto Focus Drive) AF Motors. DC AF Motor lenses wouldn't appear until later. DC Motor and AFD Motor DO NOT support Manual Focus override when the AF/MF is set to AF.

-Demetrius

Current Gear: EOS 5D Mark IV, EF 16-35mm F/2.8L III USM, EF 24-70mm F/2.8L II USM, EF 50 F/1.8 STM, EF 85mm F/1.8 USM, EF 70-200mm F/2.8L IS III USM, 470EX-AI & 600EX II-RT

Retired Gear: EOS 40D & Sigma 17-50mm F/2.8 EX DC OS HSM