I spent an hour or so shooting on the Upper West Side here in NYC with a borrowed 24 - 105 L series lens. I set the camera to monochrome and in-camera sharpening and contrast to 100%, which was perhaps a bit too much. Though I suspect there's a Z-Finder in my future, I didn't have much trouble getting sharp focus just using the plain old LCD screen.
I've currently got the 17 - 55 2.8 but miss having more reach on the long end of the zoom, and wanted to see how the 24 - 105 performed. I'm quite pleased with the results even though it's *only* an F4 lens.
Shot at 1080/24p, transcoded to XDCam EX codec with MPEG Streamclip for editing in FCP.