lamiaceae wrote:
Lens hood for LONG telephoto lenses, yes. What protection does a lens hood on a 15mm lens provide? Not everyone is shooting birds with a 500mm to 800mm lens!
The lens hoods on wide angle lenses are usually flower-shaped. They provide minimal protection against drops. If you need to work in any hazardous environment, then yes, a clear filter is advised.
If you're doing astrophotography, that is one case in which a filter of any kind can ruin your image. Light can be reflected off the front element, to the back side of the filter, and back into the lens, creating excessive flare or a halo around what you're photographing. (Been there, done that, bought the T-shirt...)
I'd suggest that any crowd of people is a potentially hazardous environment. The beach, any sort of racetrack, manufacturing environment, chem lab, workshop... Those are all places where a clear glass filter, ND filter, CP filter, or special effect filter can protect the lens.
A portrait studio seldom constitutes a hazardous environment. If it does, the photographer has not taped down cables, or is using an insufficiently sturdy tripod, or is working hand-held without a camera strap around his/her neck, or has a medical condition!
UV filtration over the lens can cut haze in outdoor distance scenes when using a film camera. It just costs you 1/3 stop of light and does not gain you anything other than protection when you use a digital camera, or when you use a film camera indoors. A clear glass protector does not cost you that 1/3 stop of light.
Use common sense (Where am I? What's near me? Could I drop the camera? Could it get hit with something? Am I graceful, or a klutz?)
And for heaven's sake, carry insurance on your camera equipment! Individuals can purchase an inexpensive rider on their homeowners' insurance. Schools and businesses can get this sort of coverage, too.
We keep seeing this sort of thread a couple of times a month. It seems as though flogging a dead horse would lose its appeal by now.