focus question

[pjd88]

Hi, quick question.. is auto focus speed determined by body, lens or a mixture of both? I'm thinking in regards to buying a new 70-200 f2.8 lens for my k-x. Will it help increase focus speed or would a body upgrade to a k-5 be a better option?

Thanks all

 

[admirable]

lens

 

[lensflair]

lens

A few things depending on lens. A lens with a motor built in like the Nikon AF-S lenses then its all down to the lens. Some older lenses don't have an autofocus motor built in and there's a mechanical link from the body. In that case some bodies seem to have a stronger faster motor that can autofocus quicker.

In either case some cameras have better autofocus systems and can achieve focus quicker but most decent systems these days tend to be close for a static subject, moving targets are a different story and some systems seem much better at tracking the subject in 3 dimensions.

 

[da_nige]

Its a bit of both.

A 2.8 lens will AF quicker on the same body than an f4 as more light is coming in but a high end/pro body will AF quicker than a low end/consumer body using the same lens.

That said most people prefer to upgrade glass over upgrading their body

Neil