topic Re: Canon 5D Mark II locking up when using viewfinder in EOS DSLR & Mirrorless Cameras

Canon 5D Mark II locking up when using viewfinder

TerryWin — Mon, 26 Jan 2026 18:11:52 GMT

Hello everyone,

I’m new to the message board, so I apologize if this issue has already been discussed. I purchased a Canon 5D Mark II about a week ago, and it was working perfectly until last night. When taking photos using the optical viewfinder, the camera consistently locks up. I can hear the shutter activate, but it appears to get stuck, and the camera becomes unresponsive. Turning the mode dial will “unlock” it, and it resumes normal operation—until the next photo is taken.

Interestingly, the camera works fine when shooting in Live View mode. The issue only occurs when using the viewfinder. I’ve already performed a factory reset and reformatted the memory card in-camera, but neither resolved the problem.

I’m considering installing Magic Lantern to see if that helps, but before doing so, I wanted to check if anyone else has experienced this issue and found a fix.

Any insight would be greatly appreciated. Thank you.

Re: Canon 5D Mark II locking up when using viewfinder

kvbarkley — Mon, 26 Jan 2026 18:13:54 GMT

Are you set for mirror lock up or any other multiple shutter press modes? Have you tried resetting the camera?

Re: Canon 5D Mark II locking up when using viewfinder

TerryWin — Mon, 26 Jan 2026 18:21:13 GMT

I haven't setup any custom modes on the camera, but I have done a factory reset.

Thanks.

Re: Canon 5D Mark II locking up when using viewfinder

Waddizzle — Tue, 27 Jan 2026 00:53:36 GMT

“ I’m new to the message board, so I apologize if this issue has already been discussed. I purchased a Canon 5D Mark II about a week ago, and it was working perfectly until last night. “

Don’t worry about creating a new thread. It becomes confusing when people jump on an existing thread. You don’t know when or where they joined the conversation. Besides, similar symptoms doesn’t necessarily mean similar causes.

Welcome to the community! Thanks, for starting the new thread.

I see that you purchased a used camera. It is a best practice to FULLY reset a used camera. You to clear out any customizations that the previous owner left behind. You need the entire camera to be in a known state.

I see that you performed a reset already have performed a reset. Unfortunately, the reset function in the menu performs a soft reset. It doesn’t reset everything.

The only way to reset everything is to walk through the entire menu system and resetting every menu option that has a submenu. These items will often have their own independent reset, which the soft reset doesn’t touch. For example, time and date.

While the soft reset should have cleared everything without a submenu, it doesn’t. You want to CONFIRM every setting is back to its factory default. The best way to verify your settings is to compare the camera against the User Guide. You can download the User Guide and more from the product support page for your model.

https://www.usa.canon.com/support/p/eos-5d-mark-ii

Fully charge the battery. It could take an hour or more. There is a reward for doing it. You will see every menu setting. Some will stick in your head. Hope this helps!

Re: Canon 5D Mark II locking up when using viewfinder

Walter_Schulz — Tue, 27 Jan 2026 08:51:45 GMT

Behavior looks like accidentally activating Mirror Lockup (C.Fn III - 6)
Custom functions will not get affected by Factory Reset "Clear Settings".

Re: Canon 5D Mark II locking up when using viewfinder

TerryWin — Tue, 27 Jan 2026 14:26:06 GMT

Thanks for the added info Waddizzle! I appreciate it, and I'll definitely go through all the settings individually, and I'll report back with any findings and/or new developments as it may help someone else out.

Re: Canon 5D Mark II locking up when using viewfinder

normadel — Wed, 28 Jan 2026 07:58:11 GMT

DO NOT INSTALL MAGIC LANTERN in the hope it will fix your hardware problem. That's not what it's for and can further complicate things.

When in Live View mode, the mirror is always up. When in viewfinder mode, the mirror moves up and down. If it is sticking up, you have the problem you're experiencing.

Where'd you buy the camera from? Do you have a warranty that allows you to return the camera? If not, you need to have it checked/serviced by a qualified repair service.

Re: Canon 5D Mark II locking up when using viewfinder

TerryWin — Thu, 29 Jan 2026 14:17:38 GMT

Thanks everyone for your replies and suggestions. It looks like doing the factory reset AND going through all the sub menus and either turning things off or disabling things did the trick!! I appreciate the assist everyone!