Problem No. 2: Should I use a skylight filter on my lens?
Skylight filters have two jobs. One is to reduce the cool, slightly blue color cast that you might see in some of your shots, especially those taken in shade under a blue sky. With the sophisticated white balance abilities of today’s cameras, this is less critical than it was when photographers were using film (especially slide film).
However, skylight filters play a second role, protecting the front element of the lens from accidental scratches and splashes. If your camera resides permanently in an orderly studio, this might not be an issue, but if you do most of your photography in the great outdoors, it certainly will be. Replacing a filter is a lot cheaper than writing off a lens!
Problem No. 3: Should I Delete All or Format to remove pictures from a memory card?
Formatting the card is quicker, so is nearly always the better option. However, if images are ‘Protected’ during playback, they won’t be erased when you press Delete All but will be wiped if you format the card. You can flag photos as ‘Protected’ by pressing the appropriate button.