Book excerpt: This essential guide shows amateur photographers of all levels how to conquer more than 25 tricky exposure scenarios frequently found in the field. As every amateur shutterbug knows, certain exposure situations prove frustrating time and time again, whether photographing a high-contrast snow scene or getting the perfect backlit portrait. In this ready reference, bestselling author Bryan Peterson demystifies common stumbling blocks one by one, with tips and techniques for getting a great shot every time.