Issue 18 goes big on testing – we have the Fujifilm X100T, the Olympus OM-D E-M5 Mark II and the Profoto B2 light on the bench this week, as well as taking a first look at the Canon EOS 5DS. Our Camera class teaches you how to read a histogram and we talk to Dr Marek Kukula ahead of the Astronomy Photographer of the Year competition.