Last year, on my trip to India I took the Pentax 645D, a 35mm wide-angle lens and the new 90mm macro.   I also packed a Pentax K5-IIs with a 40mm pancake lens for low-light  street photography. The K5-IIs would also be my backup camera in the unlikely event that the 645D was stolen or had problems. The K5 takes the same batteries, charger and SD cards as the 645D. The body and pancake lens combined weigh about 800 grams so it didn’t t take up much space or weight if it wasn’t used. The image quality from the K5 is excellent, obviously not on a par with the 645D, but I would still be able to use the images for commercial purposes. While in Agra, shooting the Taj Mahal at dawn, the 645D suddenly stopped working. The shutter seemed to open for a couple of seconds then the screen showed just a black image. I turned it off and on, removed and replaced the battery, the lens, the SD cards, but the problem was …