Picture angel for DX Format..

Hi guys.I've NIkon D80.I wanna get wide angle zoom lens.But I already check them from Nikon website.It says different picture angles for DX Format and FX Format.If it's right,what's the point to get wide angle lens? Because difference is very large.For example 17-35 mm f/2.8 IF-ED Nikkor lens has 104-62 degree for FX Format.Same lens also has 79-44 degree for DX Format.AF-S DX 18-55 mm f/3.5-5.6G VR already has 76-28.50 degree.Why do I get wide angle lens? Is this specification just for Nikkor lens? If I get Sigma,Is it gonna be same?

Sigma will be the same. The DX-size sensor is smaller than
a 35mm film-frame, so there is a 1.5X crop factor.
You lose on the wide angle end, but gain on the telephoto
end. 50mm x 1.5 = 75mm equivalent.Do a google search on
DX Format and get a better explaination. A 50mm lens is a
50mm lens, no matter what format camera it is mounted on,
from a DX format to an 8x10 view camera, it is still a
50 mm lens. What you get on the film will differ.
/Clay

Found a good link for you here:

http://www.cambridgeincolour.com/tutorials/digital-camera-sensor-size.htm

/Clay

Thank you very much Clay.You really helped me very well.I just started to take a photograph.So I'm learning and I'm gonna learn too much thinks:)

Gokhan.

You are quite welcome.Actually,"full-frame" is a bit
misleading. If the lens fills the format that you are
using (DX, 35mm, 8x10, etc.) It IS "Full-Frame"! Ha !
/Clay

That's right Clay :))

Gokhan