Using old lens on new Nikon digital cameras

Problem solved the green spots were from the sun use your lens hood thats what its for

Sorry, but the D40x lacks an autofocus motor, depending on the lens to have one. Nikon calls such lenses AF-S. This particular lens does not have such a motor, relying on the camera to have one. The only 50mm lens currently available with an autofocus motor is this one:
http://www.nikonusa.com/Nikon-Products/Product/Camera-Lenses/2180/AF-S-NIKKOR-50mm-f%252F1.4G.html

Earlier this week the Nikon web site listed a new 50mm F1.8 lens with an autofocus motor, but then it was removed. Hopefully they will officially announce this lens soon.

It sounds like you need a new lens. This particular camera does not have an autofocus motor built in, which means it can only use lenses that have a motor already built in. Look for any Nikon lenses that have the AF-S in their name.

Amazon Search for "Nikon AF-S": http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=Nikon+AF-S&x=0&y=0

This is also a good "general use" lens: http://www.amazon.com/Nikon-18-55mm-3-5-5-6G-AF-S-Nikkor/dp/B000LWJ1ES/ref=sr_1_10?ie=UTF8&qid=1298926690&sr=8-10

Hope this helps.

Try cleaning the contacts on the lens with a cotton swab lightly dampened with rubbing alcohol.

Any Nikon digital SLR will work with this lens. However, there are two things to consider.

On cameras other than the D700 and the D3 family, the smaller sensor will make the lens appear as a 105-315mm. On the D40, D40x, D60, D3000, D3100, and D5000 cameras, you will lose the autofocus capability.

Yes. Either of those lenses will work fine on either body.

Some charts are on the web. Search for your model of camera and compatible lenses.

Nikkor 55-200mm f/4-5.6G IF-ED AF-S VR

You need AF-S or AF-I Lenses. These have the autofocus motor built in to the lense. The D40 and D40x does not have an autofocus motor in the camera body itself, while the D80, D300, D3 Etc to have the motor in the camera. You can use most old lenses on your D40x, but you will have to focus them manually.

See Ken Rockwells page for a lot of D40 / D40x info
http://www.kenrockwell.com/nikon/d40.htm

Here is Nikon's specs of lens compatibility for the D40X:


Compatible Lenses*: Nikon F mount with AF coupling and AF contacts Type G or D AF Nikkor:
1) AF-S, AF-I: All functions supported;
2) Other Type G or D AF Nikkor: All functions supported except autofocus
3) PC Micro-Nikkor 85mm f/2.8D: Can only be used in mode M; all other functions supported except autofocus
4) Other AF Nikkor*â¹/AI-P Nikkor: All functions supported except autofocus and 3D Color Matrix Metering II
5) Non-CPU: Can be used in mode M, but exposure meter does not function; electronic range finder can be used if maximum aperture is f/5.6 or faster
6) IX Nikkor lenses cannot be used
*â¹ Excluding lenses for F3AF

They do not recommend 3rd party lenses, ever