Originally Posted by richardh
there are adapters for many cameras (basically a tube) that extends beyond the lens assembly, for attaching filters and lenses.
Yes, but if one of these is fitted, the overall 'footprint' of the camera is enormously increased, and it won't fit in its case any more. If you screw it on every time, the whole object of protecting the prime lens at all times is defeated.
The solution, which I tried out unsuccessfully on my local camera shop, is push-on filter holders, which I used for many years on my first few cameras. These would sit permanently on the extending tube, and not screw into the fixed surround like an extension tube. I'm told they don't exist any more, and anyway you can't buy the plain glass UV filteer to go in it. I own several of these holders, but none of them fit my digicam.