The calibration information shows how well calibrated this lens is likely to be new, out of the box. A higher score (close to 100) indicates that you are less likely to need to calibrate the lens. The score takes into account the likely amount of calibration required, the variation in calibration across many lenses as well as the likely improvement between an uncalibrated and calibrated lens. For zoom lenses, we also use parfocality, which is a measure of the difference in calibration required between each end of the zoom range.

Summary

The summary information shows the metrics measured to build the score.

Focus Adjustment Profile

The curve is the composite quality levels across all copies of this lens.

Focus Adjustment Value Distribution

The bar height indicates the percentage of camera/lens combinations that resulted in the specified focus adjustment value.

Focus Adjustment Magnitude Distribution

The bar height indicates the percentage of camera/lens combinations that resulted in the specified Focus Adjustment Magnitude. This is the size of the focus adjustment needed to calibrate the lens, ignoring the direction.

The focus information shows how consistent and accurate the focus is for this lens, measured across all camera bodies.

Summary

The summary information shows the metrics measured to build the score.

Focus Consistency

The gauge(s) below show the average amount of error from perfect focus for this lens across all camera bodies. The value is expressed as focus adjustment units (i.e. AF Microadjustment units for Canon cameras, AF Fine Tune units for Nikon, Sony etc). The lower the value, the better the focus repeatability on this lens.

300mm

Focus Shift

The focus shift information shows how the point of best focus changes across the aperture range.

Refocus Quality Improvement

The Refocus Quality Improvement shows the typical percentage quality improvement obtained by manually focusing the lens instead of using autofocus across the aperture range.

The autofocus system on a camera typically operates with the aperture either wide open or stopped down just a little, meaning that focus shift can affect the image quality obtained from the lens.

For lenses with significant focus shift, the best quality can be obtained by manually refocusing when the aperture is stopped down, or by calibrating the lens at a specific aperture (see Peak Aperture Profile below).

Calibrated Aperture Profile

The Calibrated Aperture Profile shows the typical sharpness that can be expected across the aperture range when using autofocus on a calibrated lens.

Peak Aperture Profile

The Peak Aperture Profile shows the typical peak sharpness that can be expected when the lens is manually refocused to the sharpest image for each aperture.

This is the best quality that can be obtained from the lens at each aperture.

The wide information shows the performance of the lens when wide open. The measurements are comparisons with the values at the aperture of best image quality, and include measurements of quality, astigmatism and colour-specific quality.

Summary

The summary information shows the metrics measured to build the score.

Aperture Sharpness Profile

Astigmatism

Red/Blue Quality

The peak information shows the performance of the lens at the aperture of best image quality.

Summary

The summary information shows the metrics measured to build the score.

Peak Histo

Aperture Sharpness Profile

Astigmatism

Red/Blue Quality

The vignetting information shows how the light is attenuated in the corners of the frame across the aperture range.

Summary

The summary information shows the metrics measured to build the score.

Full Frame

APS C

Corner Brightness Profile

The aberrations information shows details of the astigmatism and colour quality changes across the aperture and focus range.

Summary

The summary information shows the metrics measured to build the score.

Quality

Astigmatism

Red

Blue

The physical quality information combines consistency and quality metrics to indicate the overall physical (electrical, mechanical and optical) quality and consistency of the lens.

Summary

The summary information shows the metrics measured to build the score.

Focus Adjustment Profile

Focus Adjustment Magnitude Distribution

Aperture Sharpness Profile

Image Motion