Understanding the Nokia Lumia series smartphones

With the release of Lumia 800 in November 2011 Nokia launched its Lumia series of smart phones running on 'Windows Phone' OS. Now the family has ten members in the cheap, mid-segment and pricey models. Prices range between Rs. 10,000 and Rs. 42,000.
Come acquaint them.

Approximate MRP for the Nokia Lumia smart phone models: Lumia 510–Rs.11000; Lumia 520–Rs.10,500; Lumia 610–Rs.15000; Lumia 620–Rs.16,000; Lumia 710–Rs.18000; Lumia 720–Rs.19,000; Lumia 820–Rs.29,000; Lumia 900–Rs.34,000; Lumia 920–Rs.41,500. Obviously, shops and online dealers must be offering better prices.