I spend time in S. African game parks every 2 or 3 years. My 'go to' lens for my K-7 has been the SMC Pentax-DA 55-300mm F4-5.8 ED, which provides flexibility for animals that are spotted close-up or at a distance. The photo of the female lion below was taken at Imfolozi game park in Kwa Zulu Natal at a distance of 50 feet. The lens performs equally well at much greater distances. The cheetah was photographed in Kruger Park at a distance of 200+ yards. The Great American Condor was photographed at the Navajo Bridge over the Colorado River near Page, AZ.

SMC Pentax-DA 55-300mm F4-5.8 ED Reviews - DA Zoom Lenses - Pentax Lens Reviews & Lens Database