Can I use sigma 300/700 lense with Nikon D3100?

I have a N80 Nikon film camera and I want to buy a digital Nikon D3100 but I need to know if I can keep my lenses, I need your help.

Yeah, you can.

You can use your N80 Nikon-mount lenses on a D3100, but with one major qualification.
Entry level Nikons like the D3100 or D5100, require AF-S lenses with built-in autofocus motors. Otherwise, your AF lenses work well, but will require manual focusing.

Here's a full list of current lenses that are 100% compatible with a D3100.
http://en.wikipedia.org/...cus_motors

For Sigma, you'd need an HSM lens.

If you want full compatibility, look at the D90 or D7000 or above.

By the way, I've never heard of a Sigma 300-700mm lens.

It won't autofocus. You can still use the lens on your camera, but you will have to manually focus it, so the lens may still have some value to you. When I first started using SLRs, all lenses were manually focus anyway, so I would not have any issue in manually focusing the lens.

However, if autofocus is important to you, and you just gotta have it (and assuming your lens even has autofocus capability), then you should look to a D90 or D7000 as they can autofocus the older generation lenses.

The one distinction between the entry level Nikon DSLRs like the D3100 (and D5100) is that unlike the D90 and higher quality cameras, they do not have an internal focus motor. That means they can only autofocus a lens that has it's own built-in motor. Nikon calls those lenses AF-S, while other lens manufacturers have their own terms.

The older designed Nikon (and 3rd party lenses for Nikon) lenses that had autofocus capability use something called a "jack-screw", which is a shaft connecting the autofocus gears of the lens to the camera. Nikon calls these lenses AF, or sometimes they are referred to as AF-D to distinguish between them and the AF-S lenses.

But the D3100 lacks the motor to turn the jack-screw for AF lenses, so it can't autofocus the older designed lenses.

Your lens will either be the older jack-screw lens or perhaps it does not even have auto-focus capability.

And the lens - if old enough - may not even allow you to use the auto-exposure capabilities of the camera. In short - as long as it is a Nikon-F mount lens, it will work on the D3100. But you may have to use it in Manual exposure mode, and you will certainly need to manually focus it.

But hey, that is what we all used to do anyway in the early days before auto this and auto that. So go for it.

And like the above statement, I have never heard of a 300-700mm lens.

Sigma has made some strange lenses over the years though.