Panaflex User's Manual, 2nd Edition

Testing PANAVISION Lenses

Every lens is unique and before any production commences PANAUSERS are encouraged to thoroughly test every lens they are taking with them.

It should be borne in mind that almost every lens gives of its best performance one or two stops stopped down from maximum aperture and sometimes least well at minimum aperture. Some lenses will focus on slightly different focus marks at full aperture compared to two stops stopped down. Some zoom lenses may have a focus shift over the zoom range, may have better performance at some focal lengths than others and may change their image size as the focus setting is changed. Some lenses may appear to have more, or less, depth of field than others or more, or less, depth in front, or behind, ...