If you use filters start with UV and polarizer filters . When you use a filter remember to compensate by increasing your exposure on your shots . Generally there is an explanation on the filter box of EF compensation and how it can be used for best results . I would not recommend buying used filters , because they can be scratched and will reproduce that defect on all your exposures . Experiment and see what works best for you . GOOD LUCK !!!!!!! Sincerely CameraNut