relmet454 Loc: Central Minnesota

Ok on a nikon C sized sensor with say a DX kit lens, is a 17-55mm that size or equivalent to a larger focal size? Or does the 1.6x factor only apply to when I use a non DX lens? Like the vast array of older lens which were made for full frame or film cameras?

MT Shooter Loc: Montana

Nikons sensors are larger than Canons sensors so they only have a 1.5X crop factor. And yes, that crop factor applies to DX as well as FX lenses. A lens' focal length does NOT change, only the sensor size does and that simply reduces the size of the lens' projected image that the camera is recording.

relmet454 Loc: Central Minnesota

Ok so the focal length stays the same it's just that it appears as if it were a longer focal length when used on cropped sized sensor? It's odd I thought maybe the lens made for a cropped sensor would have taken that into account somehow in making that lens, but I guess not - it's due to the camera rather the lens.

GoofyNewfie Loc: Kansas City

Focal length is measured the same way no matter what camera a lens is made for.
If you put a 200mm lens made for a large format camera (4x5), medium format or "Full-Frame" camera and a 200mm lens made for a DX- only camera on a DX camera, the image would look about the same. The image magnification is the same. Lenses made specifically for crop sensor cameras typically project a smaller image circle than one made for a full frame camera because they only need to cover the smaller sensor.
Here is an example showing a 50mm FF (Full-Frame) lens and a DX (crop sensor) lens at 50mm on both FF and DX bodies.