Century Field Chart. Century Precision Optics has been long regarded as one of the finest optical manufacturers in the motion picture business. Their focus charts are considered Industry Standard Issue.
The Field Test Chart has two sides. The first is the Siemens Star. The lines converge to the center. A tack sharp lens will show the star's true pattern, while soft lenses will show a grey area towards the center. Note in this picture, it's rendered at 72dpi, yielding a horrible example of the chart's crispness.
The Other side has a series of horizontal and vertical lines, all with a crisp delineation between each. Sharp lenses show true black and white, while lenses that are soft or have aberrations will yield muddy grey patterns.
Laminated card measures 8.5" x 11".