A deep submersible light may include a body defining a hollow interior and a solid state light source such as a plurality of high brightness LEDs mounted in the interior of the body. A transparent window may be mounted over the LEDs. The space between the transparent window and the LEDs may be filled with an optically transparent fluid, gel, or grease, which allows light to pass through and ambient water pressure to pass in, thus pressure compensating the LEDs by allowing them to see ambient water pressure. The transparent window may be mounted in the body for reciprocation in both a forward direction and a rearward direction to accommodate volumetric changes in the compensating fluid, gel, or grease caused by changes in temperature and water pressure as the manned or remotely piloted submarine travels from the sea surface to deep ocean depths.