Fast F mount prime lenses?

I own a Nikon D7100, although I will upgrade to a D750 in half a decade or so.

I'm looking for super fast lenses (aperture faster than f1). I have heard of the legendary Noktor F0.95 which only cost $750 for preorder. Sadly, I can't find it anywhere (and apparently it has gone up!).

Thus, I'm looking for ANY F mount lens, manual OR autofocus (although I'm leaning towards manual focus due to cost) that is faster than f1. F0.95s are probably what I'm looking for. Focal length should be around the 50mm mark (as most fast primes are).

The theoretical mathematical optical limit of apertures, as I read many years ago, is f0.5, and practical considerations of price have generally limited lenses to f1.2 max in any brand, though Canon in the late 1960s did sell a f0.95 lens (for the Canon mount of its time, obviously, and also in Leica M mount, if I recollect correctly), and indeed there's the Noktor of f0.95. Thus your gain over f1.2 would in practice be half a stop - occasionally handy in the days of film, when you had to push-process film to get 1000 ASA (ISO) or so, but fairly irrelevant in today's digital world.

Frankly, with a camera such as the D7100, you have a large range of high ISO numbers with usable image quality, so unless you are truly into photographing black cats in unlit coal cellars, you do not need to spend huge sums of money on extremely high max aperture lenses.

Buy a 50mm 1.8g. It's a great lens.
Do you realize " half a decade " is five years? The D750 will have been replaced several times by then.
The D7100 is a great camera. I'd use it till it dies…

Non-F mount here.

http://www.thephoblographer.com/2013/08/06/14-super-fast-aperture-lenses-worthy-of-note/#.Vg2vc1aAM5Y

Noktor?

http://www.kenrockwell.com/...ch/noktor/

There's nothing "legendary" about the Noktor. It's a cheaply made lens originally made for security cameras and can't cover a 35mm full frame nor an APS-C sensor without vignetting. The optical quality is perfectly sufficient low resolution security camera usage but is very poor for even the Micro Four Thirds sensors most of them are made for.

What's legendary is the 50mm Noctilux. If you ever find one of those for under $9000 US it's either broken or stolen.

You want it for the extremely shallow depth of field, but then want to use it on an APS-C sensor which works against that aim; using it on anything less than a 35mm full frame sensor is pointless. To do that you'll need to buy a Leica M9 rangefinder camera as the Noctilux comes with a Leica M mount. Not cheap…

So upgrade to a 35mm full frame body first and then invest in a far cheaper (though still not cheap!) f/1.2 Nikkor. You'll get most of the same effect for a lot less money.