IR is never going to be in focus in exactly the same lens setting as visible light.
Look at an old 35mm SLR lens. You'll see focus markings in white, with numbers for range. Behind it, you'll see similar markings in orange, and the distance in meters or feet - and the ranges are different. The white focus ranges are for visible light; the orange were for use with IR film.
Look at an old 35mm SLR lens. You'll see focus markings in white, with numbers for range. Behind it, you'll see similar markings in orange, and the distance in meters or feet - and the ranges are different. The white focus ranges are for visible light; the orange were for use with IR film.
