X10, holy filter adaptor

Yeah, a pretty straightforward solution, if you're one of those who insists on a traditional style lenshood + UV filter, is to use a 40>46mm step up ring + 46mm filter + one of those 46mm metal screw in lensshades that sell for about $6.50 on amazon. This particular lensshade isn't all that wide across, so it doesn't obtrude that much into the lower right hand corner of your view through the optical finder, and it confers some impact protection if your lens happens to collide with a piece of furniture; on the other hand, one wonders how effective the flare suppression can be when you use such a small lensshade.