Samples taken using a Pentax 645Z body (Canon EF300/4 using Eos 5DSR).
Crops are 100% from the centre of the frame and are unprocessed conversions from raw files.
Pentax-FA* 645 300mm f/4 IF @f/4Carl Zeiss Jena 300mm f/4 Sonnar @f/4Canon EF 300 f/4 L IS @f/4Pentacon Orestegor 300mm f/4 @f/4Pentax-M 67 300mm f/4 ED @f/4Kilfitt Pan-Tele Kilar 300mm f/4 @f/4General scene from which crops were taken