topic Re: Canon EOS 3 not booting up in EOS DSLR & Mirrorless Cameras

Canon EOS 3 not booting up

Vinny1 — Tue, 26 May 2026 20:24:18 GMT

I am opening this thread on behalf of my gf. She owns a Canon EOS 3 which worked fine until a few days ago. She put in the battery and the screen lit up as shown in the picture attached. We have tried another set of battery which came up with the same screen. Checked the battery with a voltmeter which looked OK to me. I looked up what the empty square and rectangle meant online and it all pointed towards a faulty battery. I proceeded to clean the battery contacts with isopropyl alcohol but no luck. We are getting new batteries to try but the lack of error code makes it hard to diagnose. We will greatly appreciate the help if anyone knows what might be going on. The film is still rolled out inside the camera. Just FYI.

Re: Canon EOS 3 not booting up

deebatman316 — Tue, 26 May 2026 22:59:32 GMT

Hi @Vinny1 welcome to the forums. Will the camera boot up with the lens removed? What lens are you using please provide the full name. Is it a Canon brand lens or a 3rd Party lens. Some more modern 3rd Party lenses don’t work on older EOS Film bodies. Canon DOES NOT license out the EF Mount. 3rd Party manufacturers must reverse engineer it. Also the E-TTL flash protocol is the same way.

Re: Canon EOS 3 not booting up

wq9nsc — Tue, 26 May 2026 23:21:54 GMT

With the battery inserted and the camera turned on, is there anything going on in the viewfinder (like the exposure metering) or is that dead also?

Rodger

Re: Canon EOS 3 not booting up

MikeSowsun — Tue, 26 May 2026 23:43:41 GMT

I think your camera has a serious defect.

With the battery removed, you should not see the "film loaded" icon visible on the top screen. Even with film in the body it should go blank when the battery is removed. Because you are seeing the "film loaded" icon, that tells me your camera is getting power, but it will not function.

Does the film canister disappear when the battery is removed? Does it disappear if you remove the film?

Re: Canon EOS 3 not booting up

Vinny1 — Wed, 27 May 2026 00:41:08 GMT

It does not boot with or without a lens which is a Canon 50mm

Re: Canon EOS 3 not booting up

Vinny1 — Wed, 27 May 2026 00:41:48 GMT

Nothing on the viewfinder.

Re: Canon EOS 3 not booting up

Vinny1 — Wed, 27 May 2026 00:44:36 GMT

With the battery in, the film cannister icon blinks. when I take the battery off, the icon disappears. I haven't taken the film off yet. We have shot almost 18 frames with this roll.

Re: Canon EOS 3 not booting up

deebatman316 — Wed, 27 May 2026 00:48:39 GMT

@Vinny1 does anything change on the top LCD or not when the power switch is moved from OFF to ON?

Re: Canon EOS 3 not booting up

wq9nsc — Wed, 27 May 2026 00:50:39 GMT

I expect a film jam would indicate an error but at this point maybe remove the film in a dark area and see if that restores operation.

Rodger

Re: Canon EOS 3 not booting up

Vinny1 — Wed, 27 May 2026 01:09:02 GMT

With the battery in, and in the ON position the film cannister blinks and in the OFF position, the blinking stops. When the battery is taken off, that icon disappears.

Re: Canon EOS 3 not booting up

Vinny1 — Wed, 27 May 2026 01:09:55 GMT

We will try that as a next step.

Re: Canon EOS 3 not booting up

deebatman316 — Wed, 27 May 2026 01:09:58 GMT

Hi @Vinny1 I have linked the manual to the camera in my post. Check pages 25 and 28 and continue I think this is what may be going on. The film may be already rewound back into the canister but be careful. EOS 3 Manual

Re: Canon EOS 3 not booting up

MikeSowsun — Wed, 27 May 2026 02:10:17 GMT

@Vinny1 wrote:

With the battery in, and in the ON position the film cannister blinks and in the OFF position, the blinking stops. When the battery is taken off, that icon disappears.

That's good news. That is exactly how the camera behaves when the roll has finished rewinding. Just open the back and I think you will find the roll has finished and rewound itself.

Even if you had only taken 18 photos, an auto rewind can happen if the film offers too much friction while being pulled out of the canister. This can happen old film which can become brittle and causes extra resistance.

Re: Canon EOS 3 not booting up

Vinny1 — Wed, 27 May 2026 16:18:04 GMT

@deebatman316 @MikeSowsun @wq9nsc, you guys were right. We waited for nightfall and got into a closet and the film had indeed rewinded itself. We took it out and the camera came back alive. Thank you all for figuring this out!!

Re: Canon EOS 3 not booting up

MikeSowsun — Wed, 27 May 2026 16:36:06 GMT

@Vinny1 wrote:

@deebatman316 @MikeSowsun @wq9nsc, you guys were right. We waited for nightfall and got into a closet and the film had indeed rewinded itself. We took it out and the camera came back alive. Thank you all for figuring this out!!

Do you still think it rewound after only 18 exposures? What kind of film were you using? Was it 24 or 36 exposure? Was it old stock, or maybe poor quality? That may have caused it to rewind early.

Re: Canon EOS 3 not booting up

Vinny1 — Wed, 27 May 2026 18:31:20 GMT

It was a Kodak Portra 400 film with 36 exposures and bought within the last 6 months, so relatively new. We were not expecting it to rewind after 18 frames so weren't paying attention to it. I still don't know what could have triggered the rewind.

Re: Canon EOS 3 not booting up

deebatman316 — Wed, 27 May 2026 18:33:39 GMT

@Vinny1 the camera has a button for mid roll rewind. You can press that button to rewind the film and switch it out. Without exposing the film to light.

Re: Canon EOS 3 not booting up

Vinny1 — Wed, 27 May 2026 21:31:50 GMT

Good to know. Thank you for the heads up. I am pretty sure we will be using that sometime in the future.