An update: after a couple of weeks/months (I don't use the HF5 every day), I decided to try the stock filters again. And... unfortunately, I was amazed by the extra clarity and speed :-( So there's no free lunch, I guess. I ordered a pair of ER3XR, let's see.

First of all, many thanks to the people who created this guide. I tried red and orange filters on my HF5. I bought metal filters (didn't realize the standard ones were soft plastic), and they were hard to insert and remove. It took me quite some time to remove them, and I thought I was going...