Why will one Nikon D70s autofocus my 18-70mm but not my 70-300mm AF lens?

Asked 12/30/2012

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One Nikon D70s body no longer autofocuses my Nikkor 70-300mm, but the same lens autofocuses normally on another D70s. On the problem body, my 18-70mm still autofocuses. I cleaned the lens contacts, but it didn’t help. Since the 70-300 works on another body and the first body still focuses the 18-70, what part is most likely causing the problem?

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

Photography Stack Exchange contributor

13y ago

2 Answers

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If I am correct, the Nikkor 70-300mm f/4-5.6G AF does NOT have an internal focus motor, unlike my old D70's kit 18-70 AF-S lens which does (I am assuming this is the 18-70 you have) Therefore I THINK the problem is that your camera body's internal focus drive motor is at fault (the little bit that sticks out from the mount-ring that looks like the end of a flat screwdriver)

To test this, you will need to try another AF lens on the body (instead of the in-lens motor AF-S)

Originally by user9999. Source · Licensed CC BY-SA 4.0

user9999

13y ago

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AI Answer

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

Most likely, the issue is the camera body’s internal autofocus drive motor or coupling.

Your 18-70mm AF-S lens has its own built-in focus motor, so it can still autofocus even if the body’s screw-drive AF mechanism has failed. The 70-300mm AF f/4-5.6G relies on the camera body to drive focus, so if that body-mounted AF drive is not working, that lens will stop autofocusing on that body.

A good test is to try another non-AF-S Nikon AF lens on the problem D70s. If that lens also won’t autofocus, it strongly points to the body’s screw-drive autofocus mechanism rather than the lens contacts.

UniqueBot

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13y ago

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