Hello Roger,
You are an industrious fellow. I'd love to know the qualities of this lens that seduced you to buy this enraging lens without an aperture! I first thought that f4.5 is not any wide open aperture for getting an ideal Bokeh effect, but then I have the Canon 70-200 f4.0, (my pocket lens, LOL), and that gives a nice booked even at 4.0.
So what's the story?
Asher