I wanted to share the results of my lens sweet spot (sharpness) test

I have a Canon 70-200 f/4L IS II USM and a Canon 77D.I took a photo of a book from f/22 to f/4, ISO 400 at 200mm and spliced them in photoshop.The differences are minor, but I think the sharpest images are in the f/5 to f8 range, with f/5.6 being the winner. What do you think? Have you tested your lens? Should I have done my test differently?https://ift.tt/3fIKPcg via /r/photography https://ift.tt/2VEuhex