We are talking about changeing the field of view without altering the position of the lens.
It certainly changes the field of view, which is the intended effect. It more has the same effect of raising or dropping or shifting the BACK of the camera and leaving the lens in the same position. Either way, the desired effect is the same--you change the field of view.
It works, professor, why don't you TRY it first before you say it won't work. You will see that it certainly does work.
OK lensbook professors, if it doesn't work, then please explain why my field of view changes just like it would if I was shifting the lens or the back around? Is this some new optical principle that you didn't read about in the lensbook? Explain why the field of view will not change with the prism in front. YES. Explain what is going on. provide diagrams. Make me understand. I want your superior knowledge. When I know what you know, perhaps the effect will vanish from my ground glass. Please help me see reality. I need your learned help to set me straight--literally in this case.
Here's why it WORKS:
http://en.wikipedia.org/wiki/Wedge_prism
now please explain how this does NOT work. Please debunk this.
OH, apparently it's not periscopic or angular--it's a "prismatic" effect. At least get your lensbook terms straight. You lensbook boys are losing your edge.