About Lens Vignetting (Light Fall-off)
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
Various views are available for all of the vignetting samples in the database.
Select the view that works best for your research/comparison.
To learn the focal length and aperture settings for an individual shot, hover your mouse over the image.
Toggle back and forth between focal lengths and/or apertures to learn the effect of such a change.
Look at the results of two lenses side by side for a clear comparison of their performance.
Make the compare-to lens the primary lens by clicking the review link contained within the results area
and then clicking on the vignetting link within the review.
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 images - then the compare-to test results appear.
Moving the mouse back and forth toggles the results - my favorite way to visually compare test results.
You can even compare a lens to itself.
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 represents the
1.6x Field of View Crop Factor
(FOVCF) found in many of Canon's Digital SLR Cameras.
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.
Lenses such as Canon EF-S Lenses only fill this inner frame with sample image.
* Imatest Pro
Norman Koren's Imatest Pro is used to plot the f-stop contours on test result images.
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.
Back to the Lens Comparisons.
