Originally posted by RawheaD Yeah, I can confirm that.
That it's a fake :-D For obvious reasons; (a) as I've said elsewhere, I'm 99.9% positive that it is physically impossible to make an f1.0 lens for PK mount;
Fast lenses for K-mount are easy to make.
The prototype 20/1.4 is the fastest in its wide-angle segment :
K 20/1.4 AL
The 300/2 is an exceptional fast tele lens :
K 300/2
The 8.4/2.8 birds-eye; is a uniquely fast super wide :
K 8.4/2.8 Bird's-Eye
The 50/1.2 is not a super big lens, in the Pentax system. It should not be all that difficult to make a faster f/1 lens.
Likewise, the 85/1.4, and 135/1.8 are easy to produce in the K mount. And they function fine.
Here are some even faster lenses for Nikon :
Rodenstock TV-Heligon 50 mm f/0.75 lens.
Repro-Nikkor 85 mm f/1
Rodenstock TV-Heligon 42 mm f/0.75.
Kowa 55 mm f/0.8.
Rodenstock XR-Heligon 75 mm f/1.1
MATI 86 mm f/1.2
"So, at least as an alternative, other visual approaches might be explored, and while doing so technical trade-offs should be accepted. My preferred choice is shooting with fast lenses at wide aperture settings. In fact, the wider the better and don't let the f/1 barrier hold you back....
Remember f-numbers are specified for infinity focus. Moreover, due to the various optical designs, even greater variability is introduced. Thus, when the pupil magnification (p) is factored into the equation, some of the seeming blindingly fast lenses fade into the not-so-extreme category. However, any of these lenses still are much faster than a Micro-Nikkor set to an equal magnification.
The advertised large-aperture value of fast lenses is valid only for infinity focus and when they cover their designated image format. Step way outside these parameters and the effective aperture may be significantly reduced (as shown in the Table above)."
Rodenstocks : 64 mm f/1.25, 95 mm f/1.4 and 100 mm f/1.5 lenses.
Need for Speed: Very Large Aperture Lenses
Some of these, could likely be used on Pentax as well.
And the Canon 50/1 lens, was 985 grams. 8,1 cm length, with USM.
A K-mount 50/1 lens would not be difficult to make. But they need to look at production cost, compared to how many would buy. I would much prefer that the 20/1.4 went into production instead. But some might like the large aperture 50/1, when used on crop cam.
And the variaty of special primes, are what set Pentax aside from other brands.