You can do it that way, which is actually the best way, but your camera becomes IR permanetly. A few camera shops and online I have asked about the filters said they arent that great on a DSLR due the built in IR cut off filter they have. The range is very narrow, that you dont get the quality like you do with a real setup. I wanan give it a shot though, but the filters are essentially black, so it appears you have to compose, set to manual focus, install filter, then shoot and try and guess on the exposure settings.

IR shots look so crisp and the contrast is just godly when converted to black and white.