@Jay: I was wondering if it was that or window behind you. The light is clearly from above, but it doesn't have that stark contrasty look that often accompanies a flash. Perhaps because of the black background?
One of the nice aspects of the 40D is that I found its pop-up flash to be less harsh than others...
....if you look close at the petal on the top left you can see the direct shadow of the flash on the bottom petal...
I think the dark background enhances the soft appearance...and shooting with the 135 had me at a distance from the flower and that helped to soften the light...
Window light had little if any effect on the shot...
I actually use other lenses as well.... sometimes.
25/2 ZE
f/5.6
f/11
50/2 ZE
f/2.5 (yes, I first left the f/2.5 from the CV but I actually aperture bracketed the shot and I liked this one the best even though it's not in perfect focus)
f/8
Ah well, can't deny the CV 125 gets around 40% of all shots
f/2.5