by David Douglas Duncan. Harper & Row, $22.50. Using what can be inadequately described as a trick lens, Mr. Duncan takes color photographs which convert ordinary subjects into kaleidoscope patterns, mirages, sunbursts, and other unlikely but delightful surprises. Since Mr. Duncan is a superb photographer, he contrives more than simple pyrotechnics with the rig. There is poetry in his images, and opinion. The book includes diagrams for the curious and emulative.