Perhaps not appropriate for APUG but I got an app for my iphone called Pocket Light Meter from NuWaste. Actually I have two Pentax spot meters. an UltraPro and a Luna Pro. When away from home I always consider taking a spare just in case. The app is quite accurate and you can set the ISO and either the f-stop or shutter speed and it will show either. By touching the spot on the screen it will read that area but I don't know how many degrees it reads. It was either 99cents or a $1.99.

http://www.jeffreyglasser.com/