Why can't I find a fast lens for my camera?

Hi, looking for a fast lens for my Nikon D50 I want to have a lens that is maybe 1.4 or 1.8 and 50mm to 100mm anyone know where I can find one? I looked at KEH didn't see any.

The D50 had an Af motor built in (unusually for a budget Nikon DSLR) so any AF-D lens should work fine.

Nikon have just launched a new version of their classic 50mm f1.8, the f1.8G (which has built in AF motor for use with the D40, D3100 etc) and it may just be that these have yet to come into to stock.

Do bear in mind that supply of a lot of japanese imports have been disrupted due to the terrible natural disasters they have suffered recently.

Just buy the Nikkor AF 50mm f1.8D or the AF 50mm f1.4D. B&H has the AF 50mm f1.8 for $124.95 and the AF 50mm f1.4 for $349.95. Http://www.bhphotovideo.com

Just remember that neither of these lenses will auto focus on the Nikon D3000, D3100, D5000 or D5100 because they don't have a focusing motor in the camera body. They will, however auto focus on the D90, D7000 and above models. So don't buy these AF lenses if you're thinking about a D5100. The D5100 and models below it all require the more expensive AF-S lenses for auto focus.

The only lenses that fit your brief description would be the 50mm f/1.4, 50mm f/1.8, 85mm f/1.4, & 85mm f/1.8.

All are readily available at a wide range of prices. I've seen plenty of 50mm f/1.8 lenses for under $100, easily. The 50mm f/1.4 comes at a higher price, but is also out there.
http://photography.shop.ebay.com/Lenses-/3323/i.html?rt=nc&Brand=Nikon&_nkw=Nikon%2050mm%20af&_catref=1&_dmpt=Camera_Lenses&_fln=1&_ssov=1&_trksid=p3286.c0.m282

The 85mm lenses are great (on my wishlist) and a bit harder to find.
http://photography.shop.ebay.com/i.html?_nkw=Nikon+85mm+af&_sacat=3323&Brand=Nikon&_dmpt=Camera_Lenses&_odkw=Nikon+50mm+af&_osacat=3323&_trksid=p3286.c0.m270.l1313

Fast lenses are nice but don't forget, the larger the aperture, the smaller the ƒ-stop, the smaller the depth of field.

Shooting a picture at ƒ-1.4 from a few feet away will give you a zone of sharp focus that is only a few inches deep. This could cause you to spoil a lot of pictures because they are not in focus the way you like.

For general purpose shooting, an ƒ-2 lens is sufficient to take nearly any picture you can imagine. For the price difference between an ƒ-2 and an ƒ-1.4, you might be better off with the ƒ-2.

If you like making photos with short depth of field where the background is not in sharp focus those faster lenses can produce great images. If you are willing to take the extra time to be sure your camera is focused the way you want, go right ahead.

But, if you want a faster lens just so you can shoot in lower light conditions, the money might be better spent on a nice tripod instead.

Otherwise, I agree with George's answer.