Based on the model nomenclature used by AXIS, cameras with IR LED illumination typically have the letter 'L' in their model designation. Therefore, the AXIS M3057-PLVE MkII and AXIS P1378-LE are the cameras that have IR LED illumination built-in.

Lowering the shutter speed allows the camera's sensor to capture light for a longer duration. This can result in motion blur, as any movement of the subject or the camera itself during the exposure will blur in the final image. Increased noise, darker images, and reflections are not directly caused by lowering the shutter speed.