Pentax K on Samsung?

Started Mar 2, 2009 | Discussions thread
parallaxproblem Veteran Member • Posts: 5,335
Re: yes the AF motor is the question

Martin Frost wrote:

I am not so informed about Pentax.

The old lenses do not have an AF moter ?
So a AF pin is necessary ?

Hi Martin

Yes, an AF pin (actually a rotating screw drive) is necessary to use AF on the majority of current Pentax lenses, and also on all of the older ones that offered this feature

However personally I would say that the aperture control is even more important than the auto focus control - the aperture on all current Pentax lenses is controlled by a mechanical lever which is moved by the camera body and so it is very unlikely that this can be directly controlled by a Samsung 'NX' body either

If there is no AF control then you still have the possibility to manually focus (though it is probably not so comfortable doing this on EVF) but with no aperture linkage your only option is to take all photos at max lens aperture (or 'jam' the mechanism somehow at a smaller aperture, which again can't be changed)!

How much new lenses of the last 5 years have an AF motor ?

In-lens AF motor is quite a recent development on Pentax lenses and is mainly reserved for the larger, more expensive zooms and prime lenses. All the smaller pancake, 'Limited' prime lenses (including the newly announced DA15/4) use mechanical AF linkage to the camera body because it allows them to be smaller

The Pentax term for 'in-lens AF' is SDM and if you look at the following chart you will see all current and planned lenses that offer this feature (they include the letters SDM in their name):

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