One of the most frequently overlooked and common mistakes after a shoot: The image is not in focus. How do you prevent this from happening?
Everyone is working and moving about quickly on a set, and it just takes one little bump to be out of focus. You want to maximize your focus and be as sharp as possible by back focusing your lens. You should do this every time before a shoot, because you can never assume in what condition the lens is when you receive it.
How do you set back focus?
You use peaking marks and a focus chart. The focus chart uses The Siemens star pattern, and small texture patches and text blocks which can be used for visual assessment of image quality.
PDF: Back Focus