Originally posted by imtheguy Its more dependable than the Atomic Clock that there will be a point/counter-point thread on UV/protection filters every 6 weeks.
I make it every 3 weeks, maximum.
UV-block filters protect the paychecks of those selling them, and nobody else. With the rarest exceptions, the layers atop digital sensors block UV light. Film is sensitive to UV; digital is sensitive to IR, and again with the rarest exceptions, IR-blocking "hot filters" sit atop all digital sensors. If you'll be in an environment of airborne sand & dirt & dust, of swirling mud & blood & beer, use a clear glass filter. Otherwise don't.
Useful filters:
* Clear glass, but only when it would be madness NOT to use it
* PL (polarizer), CPL (circular PL), to reduce glare and reflections, and enhance sky contrast
--- Two CPL's, or a PL+CPL, make a variable ND filter
* ND (neutral density), to slow-down the shutter
* GND (graduated ND), for shooting a bright sky over a dark foreground, etc
* Split-diopter, to appear to extend the DOF (half is magnified, half ain't)
Specialized filters:
* Yellow, for glaring colored neon lights at night
* Red, for enhanced detail in B&W shooting
* Blue or Violet, to emulate earliest photographic emulstions
* IR (InfraRed-pass), for shooting mysterious spectra
All other filtration AFAIK can be done digitally, in-camera or in PP.