I have a Nikon D5100 with the 18-55 kit lens.

It was working fine till a few days ago. The auto focus used to work from the very next second after turning ON the camera.

But now the auto focus does not start working immediately after switching ON the camera. I have to wait a random amount of time anywhere between 30 to 60 seconds OR have to take a snap or two in manual focus (M) mode after which the auto (A) focusing starts working.

I have not changed any settings between these two scenarios. I have checked and tried various settings after this started happening.

If I have to correlate this to some event, then in most likelihood this behavior began after I removed the lens and mounted it back a few days ago. This was not the first time I did so. Once in a while I do remove the lens to see if some dust has gathered.

Can anyone suggest what might have happened or how to solve this issue?

  • 2
    \$\begingroup\$ The first thing to try is removing the battery for several minutes after turning the camera off. "Off" with your camera is really just "standby", and digital cameras are computers that sometimes need to be rebooted. \$\endgroup\$
    – user2719
    Feb 28, 2014 at 10:03
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    \$\begingroup\$ In addition to Stan's recommendation, try a different lens (perhaps you can borrow one from someone). \$\endgroup\$ Feb 28, 2014 at 11:45
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    \$\begingroup\$ In addition to the above, you could try removing the lens and refitting it a couple of times. You could also try resetting the camera to factory defaults (although it doesn't sound like it's anything to do with camera settings, but it's worth a try) \$\endgroup\$ Feb 28, 2014 at 14:03
  • \$\begingroup\$ Have you solved the problem? I am interested. \$\endgroup\$
    – Astroram
    Jan 31, 2015 at 4:46

2 Answers 2


In d5100, the "Slot empty release lock" option is set by default to LOCK. Which means that the camera shutter does not operate if no memory card is inserted.

Therefore one may say that if there is a delay in the procedure of card mounting during the start up, then this will cause an analogous delay to the auto focus operation.

The cause of the delay may be the existence of some unreadable card sectors. In this case reformatting the card can solve the problem.

The fact that the camera works with manual focus, which was mentioned by mattdm, is irrelevant.


Reformat the SD card, in case the delay caused by miscommunication between the camera and the memory. Then, reset the camera to the factory settings.

  • 1
    \$\begingroup\$ If the card is the problem, it's unlikely that reformatting it will help. Plus, that seems very unlikely given the symptoms described — the camera works fine with manual focus. \$\endgroup\$
    – mattdm
    Mar 13, 2014 at 10:53

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