I am new to DSLR camera and just purchased a Nikon D3400.

Is autofocus determined by the lens or the camera? I'm using the 18-55 kit lens and the 70-300 ASP Lens.

  • 3
    Do you mean "AF-P" and "AF-C"?
    – mattdm
    Mar 21 '17 at 17:13
  • 1
    What do you mean by whether autofocus is "determined"?
    – mattdm
    Mar 21 '17 at 17:14

Being that the question asked is a little bit vague, I will do my best to give an answer that covers all of the bases.

First, the TL;DR answer: if the lens is labeled AF-S or AF-P, it will correctly autofocus with the Nikon D3400.

The long answer: We have to understand the differences between Nikon's distinct autofocus (AF) systems. Nikon has three types of autofocus motors: Camera body motors, AF-S lens motors, and AF-P lens motors.

Camera body motors are used when lenses do not include their own autofocus motors. These are generally older or special usage lenses. Any lens labeled "AF-S" or "AF-P" do not fall into this category, but lenses labeled "AF" do. Camera body motors exist in most Nikon DSLRs EXCLUDING the D3xxx and D5xxx series. This means that the D3400 cannot use autofocus on lenses without a built in AF-S or AF-P motor. These lenses are the only ones that are focused by the motor in the camera body, as a built-in lens motor takes precedence over the camera body motor.

AF-S lens motors are what most of the currently sold Nikon lenses have. AF-S is a technology which allows any digital Nikon camera, including the D3400, to use autofocus.

AF-P lens motors are a new autofocus technology using stepper motors. Only certain cameras work with AF-P lenses. The new D3400, D5500, and D5600 work out of the box with AF-P lenses. The D500, D3300, D5200, and D5300 work with these lenses on the newest firmware. The D7100 and D7200 work with the lens, with some caveats in regards to VR. All other DX camera bodies DO NOT work with this lens. Because of the technology, and incompatible bodies will not even manually focus properly.

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