You could try a drop or two of isopropyl alcohol on the button and then press it repeatedly. I had an xpro1 that had a mfn button that was stuck and wouldn't press and it was loosened up with just a few drops and repeated pressing. -- hide signature --. Accelerating Entropy. The short answer is that the 5D III has a very advanced and highly customizable focus system. It's basically the *same* AF system that the 1D X (flagship) camera uses (with one minor nuance in that the 1D X links the metering system to the subject tracking system and the 5D III does not. EF 17-40mm f/4 L USM Autofocus Issue. 05-29-2020 03:01 PM. I hope that any of you can provide some direction. I was going to use this lens with my 5D Mark II this morning and noticed that the autofocus wasn't working. Checked and double checked my settings and didn't find anything wrong with them. The genius of Canon’s Dual Pixel CMOS AF is that when groups of pixels are assessed, the differences in read-outs from the A-side and B-side can detect focus. And in true phase-detect fashion, they don’t only see “sharpness,” but can instantly detect which direction the lens must move for sharp focus, and by how much. 01/09/2023: Help ensure your autofocus is properly aligned with a Canon Precision Alignment 01/03/2023: Welcome to CES 2023! 12/08/2022: New firmware version 1.0.5.1 is available for EOS C70 "Even if I had both the 24-70 and the 70-200, I think I'd still want the 24-105 as my third lens." Bedsides the Canon duo, I have the Sigma 24-70mm f2.8 and 70-200mm f2.8 and the Tamron 24-70mm f2.8 and the 70-200mm f2.8 and still I have the 24-105mm f4. Matter of fact I have/had two of them! It Canon's LP-E6 batteries are used in all sorts of devices, from the Canon 5D Mark II, 5D Mark III, and 7D cameras, to external monitors like those from SmallHD -- and even in other accessories used to power filmmaking gear. If you happen to own or use Genuine and Third Party LP-E6s, and you've had issues charging them in the Canon LC-E6 charger, the company has just issued a product advisory Auto focus is focusing on a different part of the image than the one you want. To avoid this, use auto focus on a different point of the subject. Depending on the subject, you might get good results with manual focus. Depth of field - A deeper depth of field can help avoid out of focus images. The depth of field is the range of the image that eoPkIQ.