2 unrelated beginner's questions: 1.) Is "International Standard" back the same as "Graflock" style? If not, what are the advantages/disadvantages of each? 2.) 4x5 format requires an image circle of at least 161 mm. The Rodenstock Grandagon 35mm and 45mm lenses have an image circle of 125 and 131mm respectively, yet ar e advertized as covering 4x5 format in the B&H Source book. How does this work? Am I missing something??? I apologize for my ignorance...