Quote Originally Posted by peted56
What you need to know is the crop factor of the D-SLR you want, for ease let say it's 1.5.

This means the 80-400mm becomes a 120-600mm effective size, thats sort of 5 times zoom but only across the range of that lens. A "normal lens is aound 50mm "effective" size or about a 34mm, to be the equivalent of the "standard" wide angle of say a 28mm you need to drop the size to around 18mm.
Not quite true. Only the field of view is changed. Everything else stays the same. For example, perspective and magnification are linked to the real focal length of the lens, not the "35 equivalent.." Look through the camera using a 50mm lens. It looks just like what you'd expect from a 50mm lens other than it being narrower.