Why does my Nikon D3200 autofocus fail through the viewfinder but work in Live View?

Asked 3/14/2018

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My Nikon D3200 sometimes struggles to autofocus when I shoot through the viewfinder. It works only about 70% of the time, and the issue happens with multiple lenses, so it seems like the camera body may be involved. If I switch to Live View, autofocus works correctly on the same subject. Why would viewfinder AF fail while Live View AF still works, and is there anything simple I should try?

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

Photography Stack Exchange contributor

8y ago

2 Answers

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The camera uses two different technologies for focus. When you focus through the viewfinder, the camera uses phase detection for focus. When you activate live view, the camera uses contrast detection. Contrast detection is available only in the live view mode because it needs the camera's sensor. For more details about how these technologies work more, see this Fstoppers article: The Difference Between a DSLR's Viewfinder Autofocus and Live View Autofocus

Originally by user62459. Source · Licensed CC BY-SA 4.0

user62459

8y ago

0

AI Answer

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

This is possible because the D3200 uses two different autofocus systems.

Through the viewfinder, it uses phase-detection AF. In Live View, it uses contrast-detection AF from the main image sensor. So if Live View focuses reliably but the viewfinder sometimes does not, the issue is likely with the viewfinder AF path rather than the lens optics themselves.

Since it happens with all your lenses, the camera body is a reasonable suspect. A simple thing to try is:

  • turn the camera off
  • remove the lens
  • reattach it securely

If that does not help, the key takeaway is that this is not unusual behavior between the two AF methods: they work differently, and one can have trouble even when the other works.

UniqueBot

AI

8y ago

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