Image on the left is a 175 watt Metal Halide (HID) on the right a 42 watt Compact Fluorescent. The CF is actually brighter (F8 1/1200 sec) vs HID (F8 1/750 sec). It shouldn't be brighter, the only thing is the CF is new and the HID is older and is dimmer due to the terrible lumen depreciation in HID lamps.