Yes, that's true. All my IR pictures are made with an IR filter (Hoya R72 probably was the code name). Well, do you know how to make pictures with IR filter? (you can reply here)... Anyway, it's not hard at all making those pictures with an IR filter, at first I didn't get it how to make them step by step because many users were writing these "manuals" so abstract.... Let me know, but I definitely would recommend buying an IR filter. No doubt about that.
Nice photos. But most of dslr has IR filter covered sensor. The true hardware to IR photography is self made modification. People remove the filter. But its very complicated, you loose the guarantee, and probably destroy the sensor if any mistake done