I've been interested in infrared photography for a little over a year and was thinking about putting an IR filter for my Sony A100 (67mm fliter) on my x-mas list. As I looked around B&H's site it appears that you not only need the filter, but also a special infrared film. After doing a quick search, I see that DSLRs have a special filter between the lens & the sensor to block infrared light...and I definitely don't want to do away with this until I have butt-loads of money to afford buying a second DSLR and turning the old DSLR into strictly an IR-DSLR. What affect will the screw on IR filter have if I don't remove the IR filter in the camera body? Thanks!