K-mount adapters for Pentax new-mount cameras

Started 11 months ago | Discussions thread
Alex Sarbu Forum Pro • Posts: 10,054
Re: Something to think about...

Anders_Nilsson wrote:

Alex Sarbu wrote:

Barry Pearson wrote:

Alex Sarbu wrote:

The D FA* 50mm required an unprecedentedly (at least, for Pentax) tight construction.

It was found - late in the process - that the barrel couldn't properly support the heavy front group, which led to a slight but significant misalignment - impacting the optical performance.

Long story short, they solved that issue with special support components. Also, the lens mount has "the highest number of screws ever used" - for structural rigidity.

What would happen when you add an adapter? Can it be rigid enough? I believe Lloyd Chambers warned about adapters introducing such misalignments.

Where might the problems lie?

Between the lens and the adapter,


Between the adapter and the camera when the adapter has this lens attached?


The ultra wides are impacted more. See https://diglloyd.com/blog/2009/20090802_1-UltraWideAlignment.html


But wouldn't the UWA be the first lenses You redo for MILC? Pentax current 10-17 is a fisheye and besides, from what I've heard, UWA's are the ones that benefit the most from short flange distances.

Maybe it would be the first, maybe not - depending on their strategy. But my position here is that a small number (2, maybe 3) of lenses is required from the beginning.

So, I guess Pentax would concentrate on an adapter for the existing teles, like the DA200 2.8 and DA300 4, which are anyway of decent performance, and then create a new UWA and a 24-70 standard zoom (if thenew camera is FF).

I read somewhere (Optical Limits?) that the DA200 and DA300 are really FF designs released for APS-C. Is this true or would it be a massive redesign necessary?

Yes, those two lenses cover the FF format - officially.


 Alex Sarbu's gear list:Alex Sarbu's gear list
Ricoh GR III Pentax K-5 IIs Pentax K-1 II Pentax smc DA 21mm F3.2 AL Limited Pentax smc DA 70mm F2.4 AL Limited +8 more
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