The chart goes to a dotted line right around 8x10, which I'd interpret as "getting dicey", and again, at what f/stop? But like I said, I have a 180 regular R., and wouldn't even consider using it for 8x10. There's more to the question than just coverage. But I have my own standards, and don't give a damn what certain labs might once have done. How many of you would choose a 90mm lens for 4x5? - same mag ratio. Let's just say that I'm in the camp of those who would consider a WA enlr lens to be only a last act of desperation for lack of a better option.