50mm f/1.2 on nikon d7000?

I'm looking into buying the 50mm 1.2 for my nikon d7000,

will it work and is it worth buying the 1.2 over the 1.4?

i already own the 50mm 1.8.

Why are you buying it? For some people, it is absolutely worth it. If you can afford it, and want really shallow DOF, better bokah, and better optics, the go for it. If you don't have a stable of lenses and are not being held back creatively by the 1.8, then it probably is not worth the purchase and you should get something else.

Unless you buy a third-party focusing screen, the 1.2 will be very difficult to use wide open.f1.2 lenses have a unique look wide open, really dreamy and surreal, which is very rarely practical. I bought a Nikkor 55 1.2 at a yard sale, and I find that I rarely use it, since my 50 1.7 is sharper, a quarter of the size, and a quarter of the weight, in addition to having AF.

The only advantage the f1.2 has over the f1.4 and f1.8 is the depth of field will be narrower, may be a little too narrow if your close to the subject, in that the eye could be in focus, but the tips of the eye lashes not, the DOF can be that narrow, not quite that bad on the APS sized sensor of the D7000, but still super critical on focus. If your thinking of the same lens that I have seen it's manual focus anyway, and it needs to be when used close up to the subject.

Everything else about the lens is negative, there's an optical price to pay for ultra wide apertures, it will not be as contrasty or as 'tack' sharp wide open as your f1.8 is wide open, probably more accurate to say the lens will be distinctly 'softer' especially in the corners of the image, f1.2 lenses loose 'flat field' (the ability to keep focus into the corners of the image), it's a function of optics, not a fault. Chromatic aberration will be worse and distortion will not be as well controlled. All this for just a stop wider than the lens you already own.

Stop the f1.2 down to f1.8 and the f1.8 will still be a better lens. Pentax made a few f1.2 lenses in the 70's and 80's, nobody buys them for their optical properties, but for their rarity and collectible value. They're not bad lenses it just that f1.2 seems to be a step too far optically.

Bokeh refers to the quality of the blurred parts of the image, not to the blur itself, which is just called blur, the f1.2 lens only has 5 aperture blades so the blur will be more defined and not the homogeneous blur of good Bokeh you get from the rounded apertures of more modern lenses.

The f1.4 is a middle point between the other two lenses, some would say that f1.4 is as wide as a 50mm lens can be made and still keep good optical properties.