Maybe this website will provide you with the information you need:
Here's an article that explain the identity prism in pretty good detail: Also, here's an article which applies the prism - or rather extends the concept of the prism to the Indian Tea industry. While it isn't strictly an application of the prism, it ...
No metering unless you buy a metered prism(lots of $$). Even with the metered prism, you still get no autoexposure-it's just a built in TTL meter. The 503CW does support TTL flash, but only with compatible flash units. No autofocus either under any c...