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Lens test chart
A chart to print: sharpness, distortion, focus.
What it does
A chart to print, to test a lens (new, used, or after a repair). Print it at 100 % (actual size), not “fit to page”: the 50 mm ruler lets you check.
- Sharpness: fill the frame with page 1, parallel to the sensor, on a tripod. The stars show sharpness in the center and in the corners (the closer to the center the lines stay separate, the sharper); straight grid lines that curve show distortion; darker corners show vignetting.
- Focus (front or back focus): lay page 2 flat, shoot it at 45° wide open, focusing on the 0 bar. The sharp area should be centered on 0.
- Compare at several apertures (wide open, then f/5.6 or f/8), and with even light, without reflections on the paper (matte paper is best).
Free, no account, nothing is sent: it runs in your browser, even offline.
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