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HD PENTAX-D FA 21mm F2.4ED Limited DC WR announced
#51
@troll:
So... even after telling you how you're constantly mistyping my nick, you're still doing it. A silly attempt to annoy me?

It is, of course, possible to design a FF ultra-wide which doesn't have 3 to 1.8 stops of vignetting (that is, never falling below 1.8 stops). We know that because it was done.
It being a mirrorless lens only removes the significant constraint of needing long register distance. There's much more freedom in designing the optics.
So what we're talking about here is a deliberate decision to not better correct (optically) for vignetting, relying on software corrections instead.

That made their job easier (that is, to meet the other design criteria), together with the fact that it's a mirrorless lens. Much easier compared to a SLR lens like the D FA 21mm.
And that's exactly why the Sony and Nikon can be 20mm f/1.8 lenses, yet a bit lighter and smaller than the SLR 21mm f/2.4 lens.

Note that I'm not saying "under-engineered", I'm not saying it's a poor lens, nothing of that bullshit you're making up just to invent "attacks" on other brands.

But such explanations are wasted, because you're behaving like a pigeon: knocking over the pieces, shitting all over the board and strutting around like you've won.

(Yesterday, 07:35 AM)davidmanze Wrote:   Realistically if you can afford the DA* 21mm F2.4 ....... and it gets dropped and bends the aluminium hood and barrel, rendering the lens unusable , no worries, it's likely you have the money to have the barrel and integrated hood assembly replaced ...... !
There's a choice between addressing a low probability event (a lens falling) or preferring the advantage in day to day usage.
#52
Hi Kuznite, you weirdly rude and abusive Tokina-fan.

You keep misunderstanding the light falloff towards edges/corners in the digital age, is that on purpose to annoy us, or just deliberate ignorance?

(U)WA lenses always have shown a lot of light falloff when used on digital cameras, as have big aperture lenses. The reason I have explained already, but will do it again: most of the light fall off observed is from light loss at micro lens sensor level, not because of "vignetting".
The vignetting part can be observed when looking at "bokeh balls", it usually shows less than 1 stop at most of light loss due to "cats-eye".
This Sony lens is both UWA and big aperture, a "perfect storm" for light loss.
However, the Sony engineers have done their utmost to minimise light loss. If you would actually look at Klaus' test of said lens, you would see that the lens.... shows NO mechanical vignetting wide open at all. That is an amazing feat (not the only one for this lens, it also has very low distortion, exemplary sharpness even wide open, and very smooth bokeh).
That you keep lying about this lens being "pedestrian" and that Sony engineers "relied on software corrections" instead of engineering it better is probably because it is not a Toki... I mean Pentax product?

The easier to design lens is the Pentax one. It is less wide FOV wise, it 1 stop less fast, and no one does serious testing of Pentax lenses anyway. And even though it is more retrofocus due to the bigger distance it can sit from the sensor, and a whole stop less fast, (two reasons the angle the light hits the sensor can be a bit less extreme), it too will show significant vignetting/light loss (if anyone bothered to measure that).

Anyway, good nite kuznite, I hope you don't lose any sleep over this.
#53
@troll:
So... even after telling you how you're constantly mistyping my nick, you're still doing it. A silly attempt to annoy me?



You'll have to excuse BC, Axle ....... he as am I, are both lexdysic ..... (I hope you don't mind me spilling the beans BC Smile )
Dave's clichés
#54
(Yesterday, 08:44 AM)Brightcolours Wrote: Hi Kuznite, you weirdly rude and abusive Tokina-fan.
You're still shitting all over this thread, I see.

(Yesterday, 08:45 AM)davidmanze Wrote: You'll have to excuse BC, Axle ....... he as am I, are both lexdysic ..... (I hope you don't mind me spilling the beans BC Smile )
No, I don't have to excuse it. That thing has issues way beyond dyslexia.
#55
Smile 
(Yesterday, 09:02 AM)Kunzite Wrote:
(Yesterday, 08:44 AM)Brightcolours Wrote: Hi Kuznite, you weirdly rude and abusive Tokina-fan.
You're still shitting all over this thread, I see.

(Yesterday, 08:45 AM)davidmanze Wrote: You'll have to excuse BC, Axle ....... he as am I, are both lexdysic ..... (I hope you don't mind me spilling the beans BC )
No, I don't have to excuse it. That thing has issues way beyond dyslexia.
You have shown your true troll nature (was that by design or by accident?) by using the kindly provided by yours truly escape route: only commenting on an insignificant line and ignoring the substance which proves your lies.

No hard feelings though, kuznite.

And dave, it is OK Smile
#56
(Yesterday, 09:11 AM)Brightcolours Wrote:
(Yesterday, 09:02 AM)Kunzite Wrote:
(Yesterday, 08:44 AM)Brightcolours Wrote: Hi Kuznite, you weirdly rude and abusive Tokina-fan.
You're still shitting all over this thread, I see.

(Yesterday, 08:45 AM)davidmanze Wrote: You'll have to excuse BC, Axle ....... he as am I, are both lexdysic ..... (I hope you don't mind me spilling the beans BC )
No, I don't have to excuse it. That thing has issues way beyond dyslexia.
You have shown your true troll nature (was that by design or by accident?) by using the kindly provided by yours truly escape route: only commenting on an insignificant line and ignoring the substance which proves your lies.

No hard feelings though, kuznite.

And dave, it is OK Smile

Sorry BC ...... we've both been keeping this ashamed secret for years ....... now it's out in the real world ..... in print .......
    
           OMG !!
Dave's clichés
#57
@Kunzite and @BC:

If you feel some shiver on your back, it's coming from the cold and angry eyes of one admin staring at you. Please read this as a warning to stop the silly kindergarten nonsense and get back to the actual topic.
Editor
opticallimits.com

#58
The unassailable truth is that Pentax (K) is never going to out-spec a mirrorless ultra-wide. They can get high quality, sure, but at the cost of size and/or aperture. And that's only because of the long registration distance a mirrorless lens doesn't have to cope with.
The f/2.4 maximum aperture for the D FA 21mm is an excellent compromise (with the reserve we have yet to see it's full optical performance). It makes the lens not too large, which is a must in the Limited line. One extra stop, and you'd probably have a lens the size of the D FA* 50mm.
For some, it's a deal breaker; for others, it's a small price to pay for an optical viewfinder. Guess which of these are actually interested in the lens.

OTOH the D FA 21mm Limited is quite ambitious, with 1 Super ED element, 1 aspherical element, 3 ED elements and 1 ED aspherical.
That can't be directly compared to other lenses, of course, but it's clear they did put some effort. It seems I'm the only one around looking forward to see what it can do.

And that I'm the only one around interested in Pentax, and I'm not talking about Othering.
  


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