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I have a Canon EF 50mm f/1.4 that refuses to autofocus. When I mount the lens, turn on the camera, and press the buttons to begin autofocusing, nothing happens. I don't even hear the AF motor trying to do anything. I read that Canon has issued a service notice for this lens related to focusing problems, but my serial number starts with 18..., putting it well outside the range of numbers covered by the notice.

I can focus the lens manually. The lens in question fails to focus on either of two bodies, and all my other lenses continue to autofocus on either body without any problem. The batteries in the bodies are fully charged. The contacts on both the camera bodies and the lens look clean, shiny, and undamaged.

Short of sending it in for repair, is there anything I can do to get the lens working again?

  • Do you use a lens filter with it at all? Mine refuses to focus with one. – Crazy Dino Feb 12 '18 at 22:33
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    Just a UV filter. But it's working again (see below), and it still has the filter on, so I'm pretty sure that was never a factor. – Caleb Feb 12 '18 at 23:17
  • If it plays up again, always another factor to check! (And mine was always tempremental) – Crazy Dino Feb 13 '18 at 10:12
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I was able to solve the problem with the following steps:

  1. mount the lens on the camera
  2. turn the camera on and set the AF mode to Servo
  3. set the lens to AF mode
  4. hold the focus button
  5. move the focus ring on the lens a bit

Once I moved the focus ring with the focus button held down, the lens came to life and started to autofocus properly.

I'm not sure that the lens is really fixed, or that it was broken in the first place. It seems more like the AF system was just stuck and the procedure above helped to get things moving again. The lens is eight or nine years old at this point, and the focus ring doesn't turn as smoothly as it once did, so it might benefit from a trip back to the mother ship for a lube job in the not-too-distant future anyway.

Note: Even though this lens has manual focus override, I wouldn't normally recommend using manual focus while the camera is autofocusing in Servo mode. It doesn't accomplish anything useful, and it feels wrong.

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    The focus ring on mine got "gritty" feeling after ~5 years in - but I also used it for the bulk of my rock climbing shots while my hands were covered in chalk. I ended up replacing it when the autofocus began to no longer nail the focus and just assumed chalk, grit, and dirt had made it inside the lens. It's a shame - another couple of years and I might have been able to verify this behavior. (I actually got a good deal of in store credit for the beat up little guy. The swap to the STM was nearly priceless) – Hueco Feb 12 '18 at 20:41
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    Most reputable testers have also found the new STM to be a slightly better performer at common apertures than the 50/1.4. The "stuck focus" issue is well known with regard to the 50/1.4. Always taking care to be sure the lens is parked at infinity when not using it will help avoid the problem, as it is caused by the front of the lens being bumped, particularly from the side, when the focusing mechanism is extended for closer focus. – Michael C Feb 13 '18 at 1:36
  • This answer surveys the three basic 50mm prime options for Canon users. (The EF 50mm f/1.2 L is not a "basic" option at $1K+). – Michael C Feb 13 '18 at 22:29

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