Teleconverters - crop or convert?

[losfp]

I know how camera sensor "crop factor" works, ie: on a Nikon DX camera, a 200mm lens is still going to have the "look" of a 200mm lens, but the FIELD OF VIEW is equivalent to that of a 300mm lens.

With teleconverters, how does that work? Is it a crop, or a true magnification? So if I stick a 200mm lens and a 1.4x converter on my camera, is it going to have the DOF, compression etc of a 200mm lens or a 280mm lens?

I would have thought that because the TC essentially magnifies the image that it would also change the "look" of the image and not simply crop it... but I am not sure

Any thoughts?

[ATJ]

Des,

I believe a tele-converter will actually convert the lens. i.e. a 200mm lens on a 1.4X TC is exactly the same as a 280mm lens (albeit with some loss in quality and light, including maximum aperture).

[losfp]

Thanks ATJ, I thought as much, but wasn't sure...