err..i want to ask few question here..i am new with dslr camera..i plan to buy flash for my camera..when i google i can find some flash like sb-600,sb-900 etc..can i know what this sb and speedlight mean?..how i can choose suitable flash for me?..my budget not so big since i juz a student..hope u guys can recomment suitable flash for me..i am using nikon d 60..thx