Brad Hill has posted a detailed comparison review between the Sigma 500mm f/4 DG OS HSM Sports lens ($5,999) and the Nikon AF-S NIKKOR 500mm f/4E FL ED VR lens ($10,296.95) on his blog. Here is a summary:
The differences in AF performance of the Sigma Sport 500mm f4 and the Nikkor 500mm f4E VR are so subtle that they are unlikely to be noticed under normal day-to-day shooting; both lenses show a very snappy initial focus acquisition, both shift from closest focus to distant focus very fast, and both re-focus quickly and smoothly enough that they rarely miss focus on even fast moving subjects. Repeated trials of continuous high-frame rate shooting on a rapidly moving subject showed "keeper rates" of almost 90% for both lenses, but with the Sigma Sport having a slightly higher rate of sharp shots. Both lenses exhibited high focus accuracy on all 55 selectable focus points of a Nikon D5, but the Sigma Sport 500mm f4 showed a higher degree of focus accuracy on several of the outermost focus points on a Nikon D500.
There was extreme similarity in the shutter speeds at which I could hand-hold the Sigma Sport 500mm f4 and Nikkor 500mm f4E VR at and still obtain both very sharp shots and slightly less sharp "keepers" when shooting bursts of 3 shots. When I shot several longer (10 frame) bursts of shots using the various stabilization settings on the two lenses I did find some differences between the effectiveness of the settings and the lenses. I obtained a slightly higher number of sharp shots and overall number of keepers with the VR settings on the Nikkor 500 compared to the OS settings available to a Sigma 500 user without access to a USB dock and Sigma Optimization Pro software (i.e., when using the default OS "view" settings on the Sigma lens), but this difference disappeared when I used the Sigma lens with one of its OS customization settings (OS Moderate View).
I have NEVER tested any two competing lenses that are so absolutely similar in image quality (at all distances, apertures, and with or without teleconverters) than the Sigma Sport 500mm f4 and the Nikkor 500mm f4E VR. Image sharpness, quality of the out-of-focus zones, and the progression in increasing sharpness from wide open through to about f5 (where both lenses approach maximum sharpness) is virtually identical between my copies of these two lenses.
For more information, check the full directory of the test/comparison:
- 500mm Wars 1: Intro and Background
- 500mm Wars 2: Physical Characteristics
- 500mm Wars 3: AF Tuning Values...
- 500mm Wars 4: Optical Performance
- 500mm Wars 5: Stabilization and "Hand-holdability"
- 500mm Wars 6: Musings from Just Shootin'
- 500mm Wars 7: 1.4x Teleconverter Performance
- 500mm Wars 8: Autofocus Performance