I have tried a few 300mm and 400mm on prime, zoom, and addition of 1.4x and 1.7x TC, my most satisfied lens is Pentax F* 300mm f/4.5. The lens best itself for its small size and relatively lightweight compared to others. It will take the Pentax DA* 300mm f/4.0 to beat this lens in the 300mm. I highly recommend this lens for wildlife, use good TC to reach 400/500mm. It has excellent color and sharpness.
My copy is pretty beaten up but it is my most used 300mm for wildlife ever since I get it.
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