K-mount adapters for Pentax new-mount cameras

Started 11 months ago | Discussions thread
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Barry Pearson
Barry Pearson Veteran Member • Posts: 8,723
K-mount adapters for Pentax new-mount cameras

Here are some thoughts about hypothetical K-mount adapters for use with hypothetical Pentax mirrorless new-mount cameras.

How comprehensive could a K-mount adapter be?

Could it control the aperture lever? Could it drive screw-focus lenses?

The new mount would probably have a flange registration distance of perhaps 20mm or less. So the adapter would be at least 25mm front to back.

Is that enough space to fit those mechanical controls?

I've just examined my K-1ii. I think the K-1ii probably fits those controls into the first 25mm from the mount-face towards to the sensor.

I'm not certain where the motor for the focus-screw is, but even if the K-1ii doesn't fit it into that space, I can't identify a reason why an adapter couldn't.

(Ditto my K-3ii).

Would Pentax supply a K-mount adapter?

Unless they had a death-wish, they would supply a K-mount adapter if they supplied mirrorless new-mount cameras!

(Or possibly more than one adapter, but I think that would be too ambitious for Pentax).

What could adapters do?

(Apart from the obvious!)

"Skip py" posted some fascinating ideas at:

I was particularly interested in his idea of filters behind the lens.

I have 4 lenses where I could benefit from this:
Laowa 12mm f/2.8 Zero-D: no filter thread
Samyang 12mm f/2.8 Fisheye: no filter thread
Pentax D FA 15-30mm f/2.8: expensive and inconvenient 145mm filters
Pentax D FA 150-450 f/4.5-f/5.6: big 86mm filters

Now I read that Canon have a "Drop-In Filter Mount Adapter" for their new "R" mount, plus circular polarising filter and variable ND filter to start with!

(I'm not sure what their "Control Ring Mount Adapter" does).

I wonder if an adapter could incorporate a variable extension, equivalent to an extension tube? Perhaps this would introduce a new point of failure with a poor cost-benefit ratio.

What about 3rd party adapters?

Hm! Is Pentax important enough for 3rd-parties to bother?

Only if the 3rd party could bring something novel to market, for example behind-the-lens filters if Pentax don't do this.

What do adapters bring to the party?

A Pentax new-mount camera with an adapter attached is equivalent to a new K-mount camera. Pentaxians are encouraged by new K-mount cameras!

Pentax wouldn't even need to have a new-mount lens on day 1. They would already have 41 lenses (16 of them FF) ready for the new camera, plus a huge number of legacy and 3rd-party lenses.

Commentators would criticise Pentax for this, but they have lots of criticisms of Pentax anyway. Criticism is unavoidable, but at least such a camera would be newsworthy, simply because it would be unexpected.

And in practical terms, it is a myth that there have to be new lenses on day 1. The camera could be attractive enough in its own right, especially if it were bundled with an adapter.

 Barry Pearson's gear list:Barry Pearson's gear list
Ricoh WG-6 Panasonic LX100 Ricoh GR III Pentax K-7 Pentax K-3 II +27 more
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