HM100 lens fix
 

One of the biggest problems of HM100 series is attaching (particularly rotating circular polarized) filters to the front of the lens. However one of the fixes is to attach a 72 mm filter on outside of the sunshade. This filter of course will need a snap-on cover, but it solves the issue of using polarized filter with this camera.

MOOSE 72mm warming polarizer is a great choice
 

Also advice spreading a tiny bit of Vaseline on the threads. It makes taking on and off a breeze.