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What type of lens will auto-focus on Nikon bodies without a focus motor?
I have a Nikon D5000. For Nikon Lenses I know that I have to buy ones that are AF-S. Easy enough. But when it gets into third party lenses things get murkier.
When looking at off brand lenses, is there an easy way to determine if they will AF on my camera or not? Is there a similar designation to AF-S for Sigma, Tamron, etc?
Generally only Nikon lenses use the AF-S designation. Some other lens manufacturers, like Sigma, will include a designation like HSM to denote that they have a motor (HSM = High Speed Motor). Others, like Tamron, confuse the issue by including 'AF' in their designations, which on a Nikon lens would mean body-driven AF, even though they have a built-in motor.
Most retailers' product descriptions will include information on the autofocus system in any given lens. If not, Google is your friend - 'will X lens autofocus on nikon D5000' generally fits the bill. Or you can always use DPReview's excellent lens feature search tool to find all the Nikon mount lenses with built-in AF motors.
Yes, you can but it is not as straight forwards. What you are looking for are lenses with in-lens motors which fall in two categories: sonic or not.
The easiest ones to identify are the sonic ones because marketing tends to label these things. For Sigma, you are looking for an HSM lens which stands for Hyper-Sonic-Motor. This answer gives you the terminology for various brands. It is missing Tamron's PZD.
There are also standard motors built into lenses which come in different flavors. Those are harder to identify because they are not always included in the lens name.
