I'm thinking of getting my old unused xti (400d) converted to infrared using Lifepixel. I sent them an email and didn't get an answer to my question. I'm sure a few people here have used Lifepixel so hopefully someone can answer this. If I use the standard 50mm 1.8 lens calibration, will the focusing still work well with other lenses or would I be better off using the Universal option? I have the 50 1.8 but I'd like to use my 24-70 2.8L as well. Their recommendation was to send in the 27-70 but I need that lens and can't afford to send it to them. The xti doesn't have Live View which is recommended for the universal option but although I'm not familiar with it, the 24-70 does have an infrared index on the lens. Any help is appreciated.