The good news; this filter adapter is well made and takes a low profile 67mm dia. filter without any wide-angle vignetting problems. In my case, a priority was to fit a protective UV or 'skylight' filter and this adapter allows it. The fitting to the SX30 lens barrel is by means of a very positive two-bladed sprung bayonet locking ring. The force needed to rotate and lock it seems, at first, a bit high but does not strain the lens barrel. It may be worth noting that a filter cannot be properly fitted to the lens barrel itself because the grooves into which the lens cap clips are not spiral threads. In any case, sufficient clearance to avoid vignetting would be difficult with a smaller lens cap sized filter. Note that, with the adapter fitted, the now larger diameter lens front will more easily foul (say) upholstery or carpet when the camera auto-switches off after having been put down with zoom extended!
The bad news; astonishing that the adapter is not supplied with the camera. A protective filter is really essential for the SX30 with its long vulnerable non-threaded lens likely to be used outdoors.
Bottom line; a well-made essential Canon accessory. Rather expensive but it does exactly what it says and may be permanently left on the lens barrel once fixed. A star short only because I think it should be an accessory originally supplied with the SX30.