Does an EF-S lens' focal length have the 1.6 crop factor already calculated?

[bryannemarie]

For example, the kits lens that is often 18-55mm purchased with a canon rebel, since it is specifically made for crop-sensored camera, is it a 'true' 18mm focal length, just as an 18mm EF lens would be on a full frame camera (other than smaller field of view)? Or to get the 18mm focal length effect, would you still need to purchase something closer to a 10mm EF or EF-S lens?

[Waddizzle]

Okay, thanks.  I'm just a part-time math guru.

FYI, I've found a formula to convert focal length to FOV.  The formula that it implements is FOV = 2 arctan (x / (2 f)), where x is the diagonal dimension of the sensor. The FOV is measured across the sensor's diagonal, and is therefore smaller across the horizonal dimension, and even smaller across the vertical dimension.

[ebiggs1]

It's not that hard.  Just remember 46 is normal.  Anything below is WA and anything above is tele.