New lens

[thegrump]

If I am looking for a new lens for my Nikon D3100, What am I looking for to tell me it will fit my camera. Vague? OK. If I am out somewhere ( not very often lately without my camera ). But lets say I am. I find at a Garage sale, Boot sale etc. a Nikon lens that is, at a to die for price. How do I know, that, that lens will fit my camera. Obviously a size or number somewhere, but where.

[cupic]

Nikkor 35 mm f/1.8 DX great to start with and its a prime and cheap
50mmf/1.8 also a standout even lesss than the 35mm and again a prime
Ask for nikon F mount
cheers

[I @ M]

Nikon have manufactured a very large range of lenses over the years.

Of those large numbers there are only a very small number that won't physically fit your D3100.

However from that huge range of lenses that will fit your camera you will find some that are not autofocus and will not not have the necessary electrical parts to allow metering as well as having aperture rings on the lens itself instead of changing the aperture on the camera body.

Then you will find later lenses that have the feature that are lacking on the above earlier lenses but they still won't allow autofocus on your camera body.

Then you have the relatively new lenses that are fully compatible with your body for autofocus etc.

The very early lenses are labelled ai or ais and are probably not the types that you are looking for.

The later lenses can be identified by AF-D lettering and they will not autofocus on your camera.

The latest lenses that will autofocus on your camera will be labelled AF-S and they are probably the type you should be looking for.

The difference between the AF-D and the AF-S lenses are that the AF-S lenses have an electronic focus motor in the lens body. The AF-D lenses require a camera with a built in focus motor to drive the lens focus mechanically.

Having said that, you may be happy to use a manual focus lens on your camera for some applications so many of the older lenses will still work well.

You WILL need to be more specific with regard to lenses should you decide to buy one to determine whether it is suitable for your camera.

Then there are the 3rd party lenses made by the likes of Sigma, Tamron and Tokina. Once again, you will have to make sure that the lens has that electrical focus motor built in for it to work on your camera.

Confused yet?

[thegrump]

Always confused......particularly since I started to get back into taking photos. I have an 18-55 AF-S and a 55-200 AF-S. I do mostly manual focus now, but my eyes are starting to play tricks on me. ( that's the excuse I am using anyway ). Anyway Thanks I think I have all the info I need now.