What does the term "aspherical" mean when referring to a lens for an SLR camera?

Question

What would a fixed 2.8 aspherical lens be best for?

Answer 1

It means the surface of a lens does not follow the contour of a perfect sphere. On my 50mm f/1.4 for example, the front element seems to have a dimple in it.
Aspherical lenses are not necessarily better or worse than 'regular' lenses. Some lenses are simply designed with aspherical elements because that was the most efficient way.
A fixed f/2.8 lens tells you that the lens is suited for low light photography. It also tells you that the lens can achieve shallow depth of field (massive background blur) if you want. And since f/2.8 zooms are expensive for this reason, it's usually also a sign of fantastic image quality and fast auto-focus speed.

Answer 2

Yes, but with limitations. If you look at the mounting of your digital lens, it has pcb (printed circuit board) with some electronic contacts for the camera body to communicate with the lens. It is for the many, many auto features that your digital camera offers. Your analog lens cannot do autofocus, metering, measured focus (keeping one area out of focus while some others in focus), some dramatic effects you can create with a digital will be impossible to do with a manual one. Rapid shoot, sports scenes, freeze actions may be difficult but not impossible with your analog. Your digital camera manual will tell you that too. But if you just aim and shoot, with manual adjustments, why not? You can go right ahead and use it. You will be saving a ton of money too. I guess you must have been good at it otherwise you would not have had manual lenses all these years in the first place. So, you should not have too much problem because you know the basics anyway.