topic Re: EF 70-300 ii IS USM with EOS 1000F in EF & RF Lenses

EF 70-300 ii IS USM AF doesn't work with EOS 1000F

Motte — Tue, 30 Dec 2025 14:31:26 GMT

Hello everyone,
I'm new here.
Unfortunately, I haven't been able to find an answer to my “problem.”
I recently inherited a Canon EOS 1000F with an EF mount.
Since I already own EF lenses from my DSLR, I would like to use them on the 1000F. Unfortunately, neither the autofocus nor the manual focus works on my EF 70-300 ii USM when it is mounted on the 1000F. IS works. What could be the reason for this? The focus works perfectly with the same lens on my DSLR.

Older lenses also work on the 1000F with AF/MF.

Thanks.

Re: EF 70-300 ii IS USM with EOS 1000F

jrhoffman75 — Sun, 28 Dec 2025 13:05:56 GMT

@Motte wrote:

Hello everyone,
I'm new here.
Unfortunately, I haven't been able to find an answer to my “problem.”
I recently inherited a Canon EOS 1000F with an EF mount.
Since I already own EF lenses from my DSLR, I would like to use them on the 1000F. Unfortunately, neither the autofocus nor the manual focus works on my EF 70-300 ii USM when it is mounted on the 1000F. IS works. What could be the reason for this? The focus works perfectly with the same lens on my DSLR.

Older lenses also work on the 1000F with AF/MF.

Thanks.

Maybe this will help:

https://gdlp01.c-wss.com/gds/3/0300025753/02/ef70-300f4-56isiiusm-im2-eng.pdf

Re: EF 70-300 ii IS USM with EOS 1000F

SignifDigits — Sun, 28 Dec 2025 13:39:36 GMT

Perhaps the older lenses that are working are not "focus by wire" as your 70-300 lens is? I believe the Canon EOS 1000F doesn't support focus by wire technology.

Re: EF 70-300 ii IS USM with EOS 1000F

deebatman316 — Sun, 28 Dec 2025 14:13:47 GMT

@SignifDigits Actually that is NOT true Canon has had focus-by-wire lenses since 1987. The first of which lens was the EF 300mm F/2.8L USM lens. Early Ring Type USM lenses were focus-by-wire. Canon had not come up with a clutch override system yet. That wouldn’t come out till later with Ring Type USM lenses. Micro USM lenses never supported focus override with those lenses. EXCEPT For the EF 50mm F/1.4 USM lens. This lens has an additional clutch system to support focus override while in AF mode. Without causing any damage to the lens. Now to the OP (@Motte ) please turn off the LCD screen on the lens. This should allow AF & MF to work now. Older cameras have slower communication speeds between the lens and the body. The camera isn’t fast enough to drive both the screen and the AF motor. The camera can’t even drive the AF & Aperture control at the same time. So this is done sequentially instead.

Re: EF 70-300 ii IS USM with EOS 1000F

SignifDigits — Sun, 28 Dec 2025 15:14:32 GMT

@deebatemen316. Thanks for that note. I had looked up that fact about the first lens in 1987, but I also looked up that not all cameras supported it in that timeframe and it appeared that the Canon EOS 1000F in fact did not support focus by wire technology. Thanks for the correction!

Re: EF 70-300 ii IS USM with EOS 1000F

deebatman316 — Sun, 28 Dec 2025 15:48:11 GMT

@SignifDigits actually that is a common confusion. These cameras lack a setting called “USM lens Electronic MF”. This DISABLES the electronic focus ring on the lens. This doesn’t stop focus by wire from working on older cameras. Note Focus Override doesn’t work with the camera set to Servo AF or AI Focus. This restriction is still in place today in EOS R series cameras. Now IS is a feature of the lens and always works with some exceptions. IS doesn’t work with the mode dial set to certain modes or self timer. The viewfinder may appear shaky. Or there maybe a “jump” when the picture is taken. This DOES NOT affect the exposure. I tested a copy of that lens on my dad’s old EOS 650 and everything worked as normal. The lens wouldn’t work correctly with the LCD screen turned on. This is a hardware limitation on the camera’s end. As cameras got faster communication speeds between the lens and body got faster. The communication transfer is too slow for the LCD screen and AF motor to be active at the same time. In fact the manual for the lens says that. It also states that the Nano USM AF motor’s speed slows down. When I used that lens on that camera it was noticeable that the AF motor was slower. Compared to it being mounted on my EOS 5D Mark IV or EOS 40D. Nano USM is more optimized for newer DSLRs like the EOS 5D Mark IV and DPAF. Along with more AF points. The lens works with my EOS 40D but you can tell the Nano USM AF motor slows down. In live view the electronic focus ring is powered at all times. So can you please provide that source on where you found focus by wire lenses being incompatible. If that were the case you couldn’t manual focus at all. There’s a lot of misinformation regarding STM being incompatible with EOS AF SLRs. That’s simply not the case either. They work the same way as older Ring Type USM lenses with electronic focus rings.

Re: EF 70-300 ii IS USM with EOS 1000F

Motte — Sun, 28 Dec 2025 17:34:17 GMT

Thanks for the quick replies. I could have thought of looking in the lens manual myself...

I tried a few different things:
- The lens display is off (and won't turn on at all)
- The camera is turned on when the lens is screwed onto the camera
- Waited after zooming
- Waited several minutes after mounting
- Flash is not used
However, manual focus and autofocus still do not work.
If you find a point that is already in focus, the camera recognizes it and emits the familiar sound.

Turning off the IS doesn't change anything either.

Maybe the camera is just too old?! Then I'll probably get an EOS 30V...

There is no film in the camera at the moment, does that make a difference? It can still be triggered.

Re: EF 70-300 ii IS USM with EOS 1000F

deebatman316 — Sun, 28 Dec 2025 18:03:30 GMT

@Motte manual Focus is focus by wire. The focus ring isn't mechanically connected to the lens elements like other lenses. have you tried setting the lens to MF and half pressing the shutter button to see if it will work. No power to the lens means no manual focus because the lens needs power for it to work. Did you mount the lens with the camera off. Weird stuff happens when you don’t do that. Are the batteries good. Weak batteries cause odd stuff to happen too. Film isn't needed to make the camera work. The lens must be getting power if IS is working. What does the top LCD screen show when the lens is mounted. Does it show MF or an AF operation such as One Shot. Does the camera report the F/ stop or does it say F/00 or F/--.

Re: EF 70-300 ii IS USM with EOS 1000F

Motte — Sun, 28 Dec 2025 18:31:54 GMT

I tried to focus manually with the shutter button half-pressed, but that didn't work either.

The camera's LCD display shows apertures from 4-32, which can be set manually in Av mode.
However, the display does not show af/mf, but it also does not show this for other lenses where the focus works. However, the camera registers whether mf or af is activated. With mf, I can release the shutter without having focused. With af activated I can’t.

I tried mounting the lens with the camera turned on and with the camera turned off. No difference.

The batteries are shown as full. I'll measure the voltage later and maybe just buy a new one and test it.

Re: EF 70-300 ii IS USM with EOS 1000F

deebatman316 — Sun, 28 Dec 2025 18:49:35 GMT

Are you sure the lens isn't focusing have you tried it outside with plenty of contrast. Nano USM lenses focus slower on older cameras. The lens doesn't extend or move when being focused. But it will make audible noises when the AF motor is active. With AF SLRs since the viewfinder is dark its hard to tell if something is in focus or not. Especially with wide aperture aperture lenses. Do you have another EOS AF Film SLR to see if it works on that camera. Was the lens set to MF when you did the test. Some cameras won't allow Focus override until the AF system locked focus first. With the lens set to Manual Focus the camera won't stop you because with manual focus you must focus the lens yourself.

Re: EF 70-300 ii IS USM with EOS 1000F

Motte — Sun, 28 Dec 2025 20:23:09 GMT

Yes, I am sure that the camera is not focusing. Depending on the scene visible through the viewfinder, there is no sharp point and the image is very blurry. However, if you select scene (for example closer to the lens) where a sharp image section is visible and then press the shutter button halfway, a sound is heard indicating that the image is in focus. When I point to an out-of-focus area in AF mode and press the shutter button halfway, the image does not become sharp and the sound does not occur.

No noise can be heard from the motor. Nothing happens in AF mode, even after waiting for a long time.

MF does not work even when MF mode is selected on the lens (keyword: override). It also does not work when the shutter button is pressed halfway. Again, the blur does not change at all. It simply remains blurry.

Unfortunately, I do not have another film SLR with which I can test the lens.

Side note: I am not a novice in photography. I have been taking photos for several years and have used various cameras and lenses.