Recently, my images started getting blurry when shot with the 24-105 f4 L on my 5D MK IV. It took awhile to realize it misses focus when I turn on IS on the lens. I have tried other lenses, they are fine. I tried the 24-105 on my 5D MK III and it works fine, with or without the IS on. I am shooting a test pattern with the cameras on a tripod. One other thing, the image appears in focus in the viewfinder, but not the capture raw file. I did update the firmware to 1.4. 0. No joy!
Does an error message ever pop up on your camera when this happens. It sounds like your lens and camera aren't communicating properly. As a test set the camera to Av Mode and set a stopped down aperture ie smaller than F/4. Set it to something like F/8 and press the depth of field preview button. If set to its default setting the lens should stop and the viewfinder should get noticeable darker. If the camera displays an error message there could be a communication problem or the flex cable in the lens is failing. Which version of the 24-105mm F/4L IS USM lens do you have the original or the Mark II.
Thanks Demetrius. I don't have any error message. I have cleaned the lens contacts. Your DOF preview test worked as expected. I'll take it outside tomorrow and try it hand held with IS on and off.
I've shot with IS turned on before on a tripod without realizing. The camera focused the lens correctly when on a tripod. But I used a cheaper non-L lens from the late 90s. That lens was the EF 28-135mm F/3.5-5.6 IS USM lens. That lens was discontinued back in 2016 and it was often sold as kit lens for APS-C cameras. I no longer own this anymore and it was donated to a friend. I replaced the lens with the EF 24-70mm F/2.8L II USM lens.
It is often recommended that when shooting using a tripod, to turn image stabilization off on the lens to prevent the issue that you are experiencing. I don't know what the difference would be between the 5D Mk III and the 5D Mk IV cameras with the same lens on a tripod would be though. You could try mirror lockup as a test with the IS on while on the tripod, to see if it makes a difference, but you shouldn't need IS when mounted on a tripod.
I agree. It was just a happy accident that IS was on and when I turned it off, it focuses correctly. I'll try the mirror lock up tomorrow. The mk IV has dual pixel AF. Not sure how that would matter. Thanks for your help.
Before you do anything, reset the camera to factory default. Keep in mind almost all focusing issues are user error. Not the camera/lens.
BTW, stop cleaning the contacts. That doesn't help and can make it worse.
NEVER clean the contacts on the lens or camera body with a pencil eraser. A pencil eraser is abrasive enough to remove the gold plating from the lens or camera body. Canon DOES NOT recommend that you do this.
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