Don't forget the difference in construction between a UV filter (one glass element) and a CPL (two glass elements)

See this thread. link

I bought the best I could afford plus a number of step-down rings to allow it's use on other lenses.

You'll need to make sure the one you buy is ok with wide-angle; if the filter construction is too thick it'll cause vignetting. You will find some manufacturers make wide-angle versions. My Marumi works fine on my Pentax 12-24. No idea how it would work on your 10-20.

Hopefully someone here in the forum who has the Sigma will be able to advise you better.

There are plenty of reviews 'out there', and Forum members I'm sure, who will argue quite rightly that you get what you pay for.

If you compare what you have against a top of the range item from the likes of Hoya, B+W, Marumi, etc, you will see a differance, but at the end of the day if you're happy with the one you've already got, why not buy another? Hardly costs the earth, does it?

If you find you use it enough, buy a better one when you have the spare cash.

For my own part, when I bought a CPL, I did buy the best I could based on comparative reviews. I chose a Marumi DHG Super.

Yes. Bought a Marumi CP from them. Good price and service.

There was a similar post to this some weeks back. Don't worry; they're all a bit noisy!

Here's the previous post link

Drive Scubber is a privacy utility. Probably over-writes data on a HD with random characters. It's intended to remove/destroy personal data on media you intend to get rid of, ie if you sell a computer.

It's not really designed to get rid of viruses, malware, etc.

Sorry if I've missed this information, but number of shutter actuations please?

I think they're only available as a post-shot option through the Image Adjust menu

Hi Sue!

From what I've read here it appears that the actual HDD is ok; it's the USB connection thats failed.

If that's the case it will be possible to transfer the drive from its existing case to another and get it working again. Replacement cases are quite cheap and can be bought on-line or in shops like Maplins, or a computer repairers will help.

Oyen only seem to make one ext HDD; I see they also sell the external enclosure separately so with luck they'll send you one. All you'll need to do then is swap the HDD itself from the old enclosure to the new one.

Try this. link

Not specifically for photos, but simple and works well.