Anyone have any comments on this lens and its best use? My guess is that it is intended as a soft focus lens for studio use with flash, as the shutter (an Alphax) only has a top speed of a 50th of a second.

You're correct. It's a soft focus portrait lens. They must be pretty good, too. They seem to command a good price.

Well I don't know about the flash part, but f6 or 5.6 and a third isn't really that fast.

In the studio with a north light window or some 1000w floods bouncing off white boards and some nice 100 speed film, I'm guessing your exposure will be in the 1/2-1/8 of a second.

This is why B&L claimed their faster lenses could make you more money as it extended the day and allowed you to shoot on overcast days as well.