topic My 5D Mark III is not taking photos, the viewer is grainy and dark, but the video works. in EOS DSLR & Mirrorless Cameras

My 5D Mark III is not taking photos, the viewer is grainy and dark, but the video works.

lacreative52 — Tue, 07 Oct 2025 01:04:53 GMT

I did a video then switched to take a photo. The viewer is showing dark and grainy. Not sure what is happening. It is focusing but not taking the photo

Re: My 5D Mark III is not taking photos, the viewer is grainy and dark, but the video works.

normadel — Wed, 08 Oct 2025 02:40:54 GMT

By "viewer" do you mean the viewfinder, or the Live View screen ?

Re: My 5D Mark III is not taking photos, the viewer is grainy and dark, but the video works.

John_Q — Wed, 08 Oct 2025 21:34:04 GMT

Hello lacreative52,

I would also ask are you referring to the viewfinder or using the LCD screen for live view shooting? If the viewfinder is dark, install a recharged battery pack in the camera. If it is the LCD screen, what shooting mode is the camera set to, like [P] or [M] for example. In terms of the camera not taking the photo, which AF (autofocus) mode are you currently using? Does the focus confirmation light blink in the viewfinder? This would indicate that the camera was not able to focus and will prevent shooting. You may want to try cleaning the contacts on the camera and lens especially, with a clean, dry, microfiber cloth to ensure good communication between them. I would recommend starting with that. I would also suggest removing any lens filter that may be attached to the front of the lens since certain lens filters may sometimes interfere with the camera's auto focusing system. Does your camera work properly with other lenses? You can try another lens. If the issue still persists, then you may want to try resetting the camera to default settings. You can find the reset in the yellow wrench menu #5.

Re: My 5D Mark III is not taking photos, the viewer is grainy and dark, but the video works.

lacreative52 — Wed, 15 Oct 2025 20:19:33 GMT

Hello John Q, Thanks so much for your message. I am only now seeing it. To clarify- I am referring to the viewfinder. It is dark and uniformly grainy. The focus squares are visible. I removed my protective lens filter and did a manual sensor cleaning (my camera cleans the sensor automatically). My lens is EF 24-70mm 1:2.8 L, it is focusing but the trigger is not working. The camera shooting mode is set to [A] and the AF to S. I have tried it with and without the remote trigger. With the remote trigger, it lights up green but doesn't actually take the photo. I have to look around to see if I have any additional lens I can try. I believe I have a Sigma 70-200mm 1:2.8 APO but not sure if it is combatible.

Re: My 5D Mark III is not taking photos, the viewer is grainy and dark, but the video works.

lacreative52 — Thu, 16 Oct 2025 00:13:21 GMT

Hello John Q, Thanks so much for your message. I am only now seeing it. To clarify- I am referring to the viewfinder. It is dark and uniformly grainy. The focus squares are visible. I removed my protective lens filter and did a manual sensor cleaning (my camera cleans the sensor automatically). My lens is EF 24-70mm 1:2.8 L, it is focusing but the trigger is not working. The camera shooting mode is set to [A] and the AF to S. I have tried it with and without the remote trigger. With the remote trigger, it lights up green but doesn't actually take the photo. I have to look around to see if I have any additional lens I can try. I have a Sigma 70-200mm 1:2.8 APO but not sure if it is combatible.

Re: My 5D Mark III is not taking photos, the viewer is grainy and dark, but the video works.

kvbarkley — Thu, 16 Oct 2025 00:59:04 GMT

The sensor has absolutely nothing to do with focusing through the viewfinder, the mirror bypasses the sensor completely. When you cleaned the sensor did you see anything amiss with the mirror?

Is the eyepiece on the camera correctly?

Re: My 5D Mark III is not taking photos, the viewer is grainy and dark, but the video works.

jrhoffman75 — Thu, 16 Oct 2025 10:15:45 GMT

@lacreative52 wrote:

I did a video then switched to take a photo. The viewer is showing dark and grainy. Not sure what is happening. It is focusing but not taking the photo

If you are referring to the optical viewfinder what do you see if you remove the lens and look through it?