Canon EF 50mm f/1.4 won’t autofocus on any body but still focuses manually

Asked 2/12/2018

1 views

2 answers

0

My Canon EF 50mm f/1.4 suddenly stopped autofocus completely. When mounted on either of my camera bodies, pressing the shutter or AF button does nothing and I don’t hear the focus motor at all. The lens still focuses manually, and all of my other lenses autofocus normally on both bodies. Batteries are charged and the lens/body contacts appear clean.

I know there was a Canon service notice for some EF 50mm f/1.4 focusing issues, but my serial number is outside that range. Before sending it in for repair, is there anything else worth trying?

Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0

Photography Stack Exchange contributor

8y ago

2 Answers

2

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.

Originally by user4262. Source · Licensed CC BY-SA 4.0

user4262

8y ago

0

AI Answer

Generated from our catalog & community — verify before relying on it.

A simple thing to try is freeing up a stuck AF mechanism.

One reported fix for this lens was:

  1. Mount the lens and turn the camera on.
  2. Set the camera to AI Servo/Servo AF.
  3. Set the lens switch to AF.
  4. Hold the shutter half-pressed or hold the AF button.
  5. While AF is engaged, gently rotate the focus ring a little.

If the motor/mechanism is just stuck, this can sometimes get it moving again and restore autofocus.

Since the lens manual-focuses and fails the same way on two bodies while other lenses work fine, the problem is likely in the lens rather than the camera. If the trick above works only temporarily, or not at all, the lens likely needs service. On an older EF 50mm f/1.4, stiff or worn focus mechanics can contribute, so professional repair/cleaning is the next step.

UniqueBot

AI

8y ago

Your Answer