An illumination time of an illumination system and/or an exposure setting of an imaging system are adjusted by a proximity system operative for detecting a product entering a field of view in a bi-optical, dual window, point-of-transaction workstation. The proximity system includes an infrared emitter for emitting infrared light to the product, and an infrared sensor for sensing return infrared light from the product. Multiple predefined thresholds are stored for the sensed return infrared light, and a predefined illumination time and/or exposure setting are stored and assigned to each predefined threshold. Adjustment of the illumination time and/or of the exposure setting is performed by comparing the sensed return infrared light from the product in real time operation with the stored predefined thresholds.