Just wondering how many people use these. I know its sometimes important to protect your lens but a cheap filter can spoil a lenses sharpness!

I use both on my 70-200L, but what about tripod mount rings too?
They are like $150 for one and all it is, is a piece of plastic to balance the lens glass over the tripod

I use both depending on the shot I want to take and the light conditions.

Both all the time on lens, but sometimes when hood isnt needed ill just leave it reversed position how i carry the lens, if i cba to put it normally.

I use filters for sure... at least a clear one to keep the lens from scratches etc. I'm not sure how a clear one can ruin the sharpness? I can see the other ones, though, if you don't buy good, ruining the sharpness.. correct me if I'm wrong ?

I haven't used the lens hood on my wide angle, yet, but I will be!

Just lens hood, had bad experiences with filters (focus problems)...

Filters can cause focus problems? Hmmm!! That's interesting... how does that work?

im not sure if the protective ones can cause loss of sharpness, but of course the filter will be lesser quality compared to the front element.

The lens im most proberbly going to buy has a silly attachment clip on lens hood, so i can only purchase the genuine canon model. Is a lens hood worth spending 20 quid on? Im not going to use a filter, however.

I use polarizers the most because it gives richer blue skies in nature shots, or helps with exposure outdoors with wildlife.

The filter is just another layer of cheap (in most cases) glass in front of the lens.
Cheap filters are pretty much crap.
I would not want to put a 100$ (expensive filter) in front of my 1200$ lens...
And I would not use a filter that cost more than a lens either...(kit lens with expensive filter).
In my case it was a HOYA filter 77mm (around 60$) in front of my 24-70L and the lens would front focus by a disturbing amount.

The only filters I use are polarizers and natural density.

Just my 2 cents.