I still think it's apples and oranges.
One more time…
The discussion is not about what lenses you, as a consumer, may want
to compare to fit on your FX or DX body. The discussion is what the
price difference is for a camera company to make a lens, of a certain
focal range, either a DX or an FX lens.
If I had a 17-55 on my DX body and I wanted to get a similar lens for
my FF body, I'd look at a 28-70 or 24-70.
Yes, we can all multiply 17 and 55 by 1.5 and come to the same
conclusion. Please understand nobody is disputing that these lenses
afford roughly the same field of view when used FX to DX. But again,
that is not the discussion that was put forth by Kent. His comment
was that –for the same focal length– DX vs FX doesn’t seem to save
you much.
-Suntan