f/1.4!

The Olympus 50mm f/1.4 OM lens has not been manufactured in decades. There is a fairly steady supply of them on ebay, where they fetch between $70 and $100. I bet the market for them has gone up since they became popular fitted with an adapter on micro-four-thirds cameras. In this configuration the camera can only be used with stopped down metering and manual focus. Which, in some ways, is cool in itself. The adapter was about $30.