Polarizers and UV blockers

[Davo]

i am getting a canon s5is .  I am not familar with lense hoods and adapters and the screw on polarizers or UV filters.  The hood is inexpensive and needed to add teh filters.  Should I and under what circumstances should I use a Uv or polarizer if at all.  I was looking at the lense hood for lense protection and I have been informed helps with unwanted glare. Any opinions.

[George Tsoukalas]

This is a pretty good discussion of it. Jawge
 http://www.mat.uc.pt/~rps/photos/filters_uv_pol/#polq1

[flyboy61]

Rule of Thumb: (R.O.T.)

Good quality UV filter on to protect your lens. All the time, it doesn't affect picture taking atall atall.

Circular polarizer: Useful to eliminate non-metallic reflections, and control sensitivity on really bright days. For my shooting style, only under controlled conditions, for a short time.  
They can and will cause a  lot of flare, when shooting into the sun. I use mine seldom. Otherwise, use the white balance program of your camera to match the light conditions, but don't for get to reset.

Lens hood: good; I use mine all the time.

[Ralphie]

Unless you know why ..... you should be using a polarizer ......., and when to use one ....... you should not bother with one. Polarizers cut surface reflection, and the resulting image gains saturation, ...ie looks less "flat". The price you pay to use one, is that they slow your camera down by about 200%. Polarizers are usually used outdoors in bright light.
UV filters do cut down on sharpness .. especially if the UV is a cheap one. Also you sometimes have reflections from the extra piece of glass.
I never use UV's I just keep the lens clean and use a lens cap.
If you do get a UV,  buy the UV the lens manufacturer makes

[Ralphie]

Also, Lenses are all now multi-coated. Which means they have been treated to improve picture quality in less than ideal shooting situations. Before multi coating, lens shades played a big role in keeping out stray reflection. Today?
A lens hood just adds bulk.
My 2 cts. from 40 years of pressing the button for a living.

[centaur]

I agree with Ralphie about UV filters. They are basically a waste of time if you use a lens cap religiously.
I like polarizers to bring out the blue in skies and cut glare on water, but you do lose about an f stop when using them, but under the right circumstances they can be beneficial.

[stickbowhntr]

good link george, thanks

[Quiet Man]

When using the circular polarizer, by rotating it you can change the hue of the blue in the sky and cause some change in other colors, real handy with fall colors.