Originally posted by Nass Hello Rustynail
The size of the polariser is usually dependant on the lens, not the body. If you find the technical details online of the lenses you bought in your package that should tell you. Off the top of my head I think it's 49mm & 52mm for the 50-200 and 18-55 respectively, but I don't have my stuff with me so don't take my word for it, I'd rather someone doublechecked this with the actual lenses
The best way to see what diameter of filter you need is to look at the lens you are going to put the filter one...
i.e. the front of most lenses (at least all the ones I own) give the lens diameter right on the front.