A light source apparatus, includes a first solid-state light source and processing circuitry. The first solid-state light source is configured to output first light. The processing circuitry is configured to control a power source to supply first current to the first solid-state light source, determine whether to change the supply of the first current to the first solid-state light source to maintain a brightness level of the first light output by the first solid-state light source at a first brightness level or within a first brightness level range, and control the power source to change the supply of the first current to the first solid-state light source to output the first light at the first brightness level or within the first brightness level range in response to a determination that the supply of the first current is determined to be changed.