The Nikon D5 is a brand new flagship DSLR camera for professionals. Aimed at sports, press and nature photographers, the 20 megapixel D5 builds on the success of the previous D4s camera with a wealth of improvements, including a new 20.8 megapixel sensor, 4K video recording, touch-screen control, and an expanded ISO range. Can the Nikon D5 justify its £5,199.99 / $6,499.95 price-tag? Find out by reading our in-depth Nikon D5 review…