Autofocusing on a Nikon?

Received this via Flickr today:

Can the AF-S Nikkor 50mm f/1.4G lens auto-focus on the D5000?

Yes.

In general, new Nikon lenses work with all the new Nikon dSLR bodies.

More specifically, for Nikkor lenses you should be looking at “S” appended to the “AF”. The letter stands for “SWM” or “Single Wave Motor” which is Nikon’s designation of a piezoelectric motor, first introduced in consumer photography by Canon as “USM” or “Ultra-Sonic Motor”.

In order to save cost, sell more lenses, and make a lighter, more compact body, Nikon removed the traditional screw motor from their entry-level dSLR bodies starting with the Nikon D40. This means that the following Nikon bodies are missing an internal AF motor: D40, D40x, D60, D3000, D5000. When buying third-party lens, you need to look for ones with announced auto-focus compatibility with any of these cameras—most notably, Tokina lenses do not seem to support piezoelectric motors currently. If this is an issue, upgrade to a Nikon D90-class camera (D100, D70, D50, D70s, D80, D90).

A more-important thing to consider with these cameras is will the lens auto-expose on these bodies? Nikon auto-exposure is the most advanced exposure system on the planet, and the more data it gets, the better it behaves. One of those pieces of data is distance-to-subject information which it gets from the lens. For marketing reasons, Nikon has decided to make it so that consumer bodies will not auto-expose without this information. This means that you need a “D” (for distance) or “G” (a D without the manual aperture control) Nikkor. On 3rd party lenses, they must have announced compatibility (which many do). For instance, in the manual prime world, they will have lenses “chipped” for “CPU” compatibility. This becomes an issue when buying old lenses or lenses that can’t be chipped like a lensbaby. If this is an issue, upgrade to backward-compatible pro body like the Nikon D300s, D700, D3S, D3X. At that point the camera will behave significantly differently than an entry-level camera (and weigh a lot more). So be warned! It might be better to shoot and chimp to adjust your exposure. :-)

3 thoughts on “Autofocusing on a Nikon?

  1. Ryan Cousineau

    Dude! Regarding those last four sentences, at that point it might be easier to buy your first dSLR body from a camera company that doesn't punish its entry-level users that way.

    I don't know how Canon differentiates its entry-level bodies, but on my Pentax K100D Super I use an all-manual Hanimex telephoto. It asks me what the focal length is when I turn on the camera (for the image stabilizer), and then shoots as a stop-down metered aperture priority system.

    The entry-level bugbear with Pentax is there's no PC-camera control (tethered shooting or time-lapse photography). On the other hand, fun manual glass is super cheap and widely available.
    My recent post The Worst Journey in the World, The Good Parts Version

    Reply
    1. tychay Post author

      I had other articles that mentioned how this affects buying decisions. I also discussed heavily the advantages of the entry level Pentax including emphasizing Pentax is unique in supported all the features of all older K-mount lenses—distance information appeared with the KAF version of the mount, but Pentax is backward compatible with all mounts. In previous articles I mentioned that the same is true for the Canon mount. The reason for this is that Canon simply decided to obsolete an entire mount in 1987. You cannot buy a Canon lens manufactured before 1987.

      (BTW, the reason it's asking for what the focal length is, is actually for the in-body image stabilzer (and flashgun), not for the exposure or focusing.)

      I don't think the lack of support of metering should be a buying decision against an entry level Nikon. The reason why is the "cheap" primes in this category meter just fine (50 1.8D), but the problem is they don’t autofocus on entry bodies. I went into that in detail. I don’t think a buying decision of a $500-$1000 camera based on the metering capabilities of a $100-$200 lens that turns the camera into a $15 toy is ethically sound.

      As for lenses for entry level cameras, I discussed kit zooms and super zooms and prime lenses, extensively.

      Reply

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