People react to cold in many different ways and have a wide range of comfort zones...although 50°F is warm to have problems with cold feet. I would suggest a barrier sock or a shoe cover if your feet are getting that cold at 50°F because your problem is related to wind heat loss. The Hydroskins work well inside the shoe and there are any number of shoe covers to use.

One thing I'd suggest is that you get a shoe for winter that is a larger size then your normal summer shoe. Trying to jam a thick sock into a close fitting shoe can result in cutting off the circulation and the result is colder (feeling) feet. I'd also suggest that you insulate the bottom of the shoe (after you get a larger shoe). Insulating the sole of the shoe has made a huge difference for me at much colder temperatures. I've added these insoles to all of my winter shoes as well as using aluminum furnace tape under the insole. The furnace tape reflects heat back towards the foot and the insoles trap a lot of air. The result is reasonably warm feet even at stupidly cold temperatures.