Astigmatism Factor – MultiTest

(See Chart Features for general chart features - changing scales, copying to clipboard etc)

The Astigmatism Factor chart shows the image quality ratio between the horizontal and vertical analysis directions.

Key:

• Red line: uncalibrated astigmatism factor (adjustment value is 0)
• Green line: calibrated astigmatism factor
• Black dotted line: astigmatism factor with manual focusing at any aperture
• Orange dotted line: astigmatism factor at ARQS calibration value (see below).

Interpretation

The Astigmatism Factor is an indication of the difference between the horizontal and vertical sharpness.

Some increase in Astigmatism Factor is not unusual as the lens opens wider, especially for fast (large aperture) lenses.

Vibration

Astigmatism Factor can also indicate that the camera is experiencing high levels of vibration during a test. This is typically shown by a high value (>5%) of Astigmatism Factor at some points but not necessarily all of them.

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