Do You Know What We're Looking At?
If you are not familiar with vignetting, please read the Canon Lens Vignetting (Light Fall-off) page to gain understanding of what attributes I am reviewing.
Using the Information
Two views are available for all of the vignetting samples in the database. Select the view (grid layout or contour results) that works best for your research/comparison. To learn the focal length and aperture settings for an individual shot in the grid layout, hover your mouse over the image.
Using the Contour Results Information Tool
Any lens/camera/focal length/aperture combination tested can be compared to any other. Select the first test on the left and the comparison test on the right. You will see the test results selected on the left until you hover your mouse over the result image - then the compare-to test results appear. Moving the mouse back and forth toggles the results - my favorite way to visually compare lens test results. You can even compare a lens to itself at different settings.
Test Shots "With UV/CP Filter"
The set of test shots for a particular lens (at its widest focal length) often include a normal thickness UV or CP (Circular Polarizer) filter in place (noted along with focal length). Compare these results with the results from the same focal length/aperture without the filter attached to look for mechanical vignetting caused by these normal-thickness filters. A slim version of the filter is required if the corner shading increases more than you are comfortable with.
What Is The Small Gray Frame In The Vignetting Sample Pictures?
The small gray frame seen in full frame lens results represents the APS-C/1.6x Field of View Crop Factor (FOVCF) found in many of Canon's Digital SLR Cameras. Nikon's APS-C sensors have a 1.5x FOVCF, so the APS-C frame is slightly tight for the full frame Nikon lenses. If you are using one of these camera bodies (and don't plan to move to a full frame body in the near future), you can disregard the vignetting results outside of the gray frame - where it is strongest.
Norman Koren's Imatest is used to plot the f-stop contours on the contour results. Pay attention to the f-stop numbers more than where lines are present on these images. The numbers are what matter as some plots include more/fewer lines which appear at different frequencies.
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