Martin - I went down this road about 2+ years ago...a lot of things you have to overcome...
1 - just taking the filter off in the mount housing does not gain you IR - there is a piece of glass infront of the sensor that has UV/IR properties...
You can see here -
2 - the peice of glass infront of the filter has two issues with it...
- it is glued on with industrial glue
- it has micro lenses in it...so after a lot of work IR conversion just is not there...
I had a company tell me that they were doing a conversion for me...cost me $450.00 after playing with it and actually sending it back two times...the AF system would not work properly...(out of focus) and the pictures were too pixelated or snowy....I took the camera apart to check it out...to find out the company just put an IR 720nm filter in front of the glass glued to the sensor...so one the focusing plain was way off (out of focus fixed) and two the uv/ir glass still there prevented clean images...
I found a second person to remove the glass filter as an experiment...did a great job of it...sent it back to me...I put the IR 720 filter back in...the images were not good at all...the IR looked great...but w/o the micro-lenses not going to happen...I looked for a company to do the micro-lens IR filter... $$$$ was way too much so I opted to go with a sony a100/a200 - a100 - 680nm and a200 720nm....
I have since moved from 35mm format to medium with my IR work...and have converted a H3D II - 31 to IR and love it...I still have the two Sony cameras...if your interested...I'll sell them lower than what I paid for them...Let me know...
I found that my SD cameras are good regular light...and I use other systems for IR...that may change over time...but even with the SD1 there are micro lenses infront of the sensor...to help with resolving power.....
Hope this helps you out.... Tony C.
PS - My IR and other images can be seen here -