Marunouchi in infrared

This is my first attempt at infrared photography. Without converting my Canon 7D, fitting the R72 IR filter on the lens, this is what I got in monochrome. Shot with a 80 seconds aperture, it amplified the effect of what a strong ND filter would have done. Note how people who have crossed the road during that 80 seconds left trailing semi-transparent images. Also, moving trees have caused ghosting. So have some of the fallen leaves on the road. I definitely need to experiment more. After all, I am expecting a different output than what an ND filter would produce in monochrome. I am a bit astonished why the sky turned out quite lighted instead of the typical dark black in IR photography. The sky was clear blue, but I have to say that in this shot, the sky between the buildings looked more of an afternoon pale white, so that could be the explanation.