[Kunzite]

All Pentax DSLRs have screw AF support. It's interesting to hear theories that the K-3 iii does not (theories contradicted by the camera's specs).

[fs999]

I'm sure if someone from Ricoh is reading this thread, he'll do Seppuku before reaching page 99

[torge]

It would be a travesty if Pentax released the K-3 III without the screwmount whilst still selling ltds.

well the days of screwmount were over in Pentax land way before the first Limited lens was designed ...

[starjedi]

I think it would be a shame if it’s f2.8, just because I like that Limiteds tend to have unusual apertures.
Functionally, I’m sure they’ll get a good balance at whatever aperture they stick on it.

I did think that the DPReview headline with f2.8 was a typo, however. I thought someone had contacted them and they’d just carried it over from the 11-18 description. That doesn’t mean it isn’t f2.8, just that confirmation isn’t there yet...

-Eric

Fully agree. Sony FE 20mm F1.8 is very sharpe at F1.8 , weighs similar to FA 31mm and can be obtained for $800. Cannot believe a 21mm F2.8 lens nowadays can sell ... Of course, some Pentaxians might accept a F2.8 lens and are willing to pay a premium on this.

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Last edited by starjedi; 12-21-2020 at 02:32 PM.

[texandrews]

Fully agree. Sony FE 20mm F1.8 is very sharpe at F1.8 , weighs similar to FA 31mm and can be obtained for $800. Cannot believe a 21mm F2.8 lens nowadays can sell ... Of course, some Pentaxians might accept a F2.8 lens and are willing to pay a premium on this.

Except, starjedi, that some of us shrug about WA/UWA lenses that have big apertures. For these FL's most usage is going to be for deep DOF I'd think.

[Kunzite]

Fully agree. Sony FE 20mm F1.8 is very sharpe at F1.8 , weighs similar to FA 31mm and can be obtained for $800. Cannot believe a 21mm F2.8 lens nowadays can sell ... Of course, some Pentaxians might accept a F2.8 lens and are willing to pay a premium on this.

A SLR ultrawide is quite a bit more difficult to make than a mirrorless one. This is one of the very few disadvantages of having a proper viewfinder.
The D FA 21mm Limited likely won't match the Sony spec by spec. They're of a similar size - both somewhat larger than the FA 31mm; of a similar focal length; but one is by necessity a quite retrofocus design. The difference might be the maximum aperture.
I bet the Pentax also has a much better corrected vignetting, a huge -3EV on the Sony (hidden by software, of course).

[repaap]

A SLR ultrawide is quite a bit more difficult to make than a mirrorless one. This is one of the very few disadvantages of having a proper viewfinder.
The D FA 21mm Limited likely won't match the Sony spec by spec. They're of a similar size - both somewhat larger than the FA 31mm; of a similar focal length; but one is by necessity a quite retrofocus design. The difference might be the maximum aperture.
I bet the Pentax also has a much better corrected vignetting, a huge -3EV on the Sony (hidden by software, of course).

I also did take a look of bokeh highlight with Sony, EDGE performance is not so good with bokehballs ghosting like that. Some issue? Perhaps sharp, yes. Perhaps too fast? This is quite common with fast wide lenses with MILC, but I believe some are willing to over look this too. Latest Nikon Z16-35 zoom was also sharp, but it is almost FE lens at widest. It is sharp. Profile correction does take care of it, so it is not a problem?

I’d say that let us wait for a when this lens actually does come out.

[Rondec]

A SLR ultrawide is quite a bit more difficult to make than a mirrorless one. This is one of the very few disadvantages of having a proper viewfinder.
The D FA 21mm Limited likely won't match the Sony spec by spec. They're of a similar size - both somewhat larger than the FA 31mm; of a similar focal length; but one is by necessity a quite retrofocus design. The difference might be the maximum aperture.
I bet the Pentax also has a much better corrected vignetting, a huge -3EV on the Sony (hidden by software, of course).

I think Sony is master of the under-engineered lens that is fixed with lens adjustments -- some even done to the RAW files. It may be fine, but I expect the DFA 21 to have less vignetting, less distortion and be better corrected before those sorts of things are applied.

[Sandy Hancock]

I suspect the next great astrophotography lens will be a DFA* - most likely in the 24mm range.

This 21 Limited will not have the speed or the perfect optical correction required. If it does I'll be a little bit disappointed, because it wouldn't really be a Limited.

And for those who want an aperture ring, I presume you don't care about weather sealing....

[Serkevan]

I suspect the next great astrophotography lens will be a DFA* - most likely in the 24mm range.

This 21 Limited will not have the speed or the perfect optical correction required. If it does I'll be a little bit disappointed, because it wouldn't really be a Limited.

And for those who want an aperture ring, I presume you don't care about weather sealing....

Agreed that it most likely won't be a great astro lens - the design choices for a Limited probably don't include coma correction or a flat focus plane. I'm really looking forward to see how the 21 renders.

About the weather sealing, Fuji has WR lenses with aperture rings, but I don't know if they are just by-wire rings* or actually mechanically coupled.

*which would be easier to seal and might work as a workaround for the lack of aperture coupler, though of course it wouldn't help older cameras.

[someasiancameraguy]

I suspect the next great astrophotography lens will be a DFA* - most likely in the 24mm range.

This 21 Limited will not have the speed or the perfect optical correction required. If it does I'll be a little bit disappointed, because it wouldn't really be a Limited.

And for those who want an aperture ring, I presume you don't care about weather sealing....

So you're saying you would prefer a lens with more characteristic "pixel dust" rather than a super corrected optical formula?

[Serkevan]

So you're saying you would prefer a lens with more characteristic "pixel dust" rather than a super corrected optical formula?

That's what Limiteds are for!

[Mistral75]

(...)
About the weather sealing, Fuji has WR lenses with aperture rings, but I don't know if they are just by-wire rings* or actually mechanically coupled.

*which would be easier to seal and might work as a workaround for the lack of aperture coupler, though of course it wouldn't help older cameras.

There is no mechanical coupling in Fujinon lenses. The aperture ring is nothing more than an additional dial.

[Serkevan]

There is no mechanical coupling in Fujinon lenses. The aperture ring is nothing more than an additional dial.

Figured, since there is no aperture lever visible from the back. Still, thanks for the confirmation!

[Kunzite]

I think Sony is master of the under-engineered lens that is fixed with lens adjustments -- some even done to the RAW files. It may be fine, but I expect the DFA 21 to have less vignetting, less distortion and be better corrected before those sorts of things are applied.

The Sony 20mm has low distortion, despite still using forced software corrections. It's one of the exceptions to the rule; not on vignetting though (3EV or so)
We know this only because the processing power of these cameras is insufficient... I bet Sony would do the corrections directly on the RAW data, before writing it on the card, if they could do that in real time.