The Nikon AF-S Nikkor 24-70mm f/2.8G ED ($1,889.95) is the standard zoom lens for event shooters and other pros carrying full-frame Nikon cameras. It's exceptionally sharp everywhere but the edges of the frame, though it lacks the optical vibration reduction system you'll find in some zoom lenses. We feel that both the Canon 24-70mm f/2.8L II USM and 24-70mm f/4L IS USM are better performers, but not to the degree that would merit a seasoned Nikon shooter to jump ship to another system.

The Nikkor 24-70mm seems a bit bigger than other 24-70mm lenses; it measures 5.2 by 3.3 inches (HD) and weighs just about 2 pounds. Its height at its shortest position is close to an inch longer than the Canon 24-70mm f/2.8, and the Nikkor's lens hood adds to its depth. But it does have the advantage of only minimally telescoping when zoomed, where its Canon counterpart extends quite a bit as it approaches the 70mm setting. The Nikon design also keeps the hood in one set position, so you won't even notice its slight telescoping action when utilizing the hood.

If you want to use a front filter with the lens you'll need to reach for one that's 77mm in size; the front element never rotates, so using a circular polarizing filter presents no problems. Like most zoom lenses, the zoom ring is located at the base of the lens and is covered in a textured rubberized material. The manual focus ring sits ahead of it and is covered by a similar material, albeit with a different texture so you can differentiate them by feel. Close focus distance is about 15 inches, which is typical for a lens of this type; when working close at f/2.8 it's possible to capture images with a strikingly shallow depth of field. The Canon 24-70mm f/4L IS USM can get a bit closer; at 70mm it has a 1:1.4 macro mode that will focus down to 7.9 inches.

I used Imatest to check the sharpness of the lens when paired with the full-frame Nikon D800. At 24mm f/2.8 the lens manages 2,602 lines per picture height using our center-weighted testing methodology. But it suffers from some uneven performance; the center third of the frame tops 3,500 lines, but the middle third only manages 1,870 lines and the edges are noticeably blurry at 1,105 lines. The middle third gets better and brings up the average score to 3,027 lines at f/4, but the edges still hover around 1,100 lines. There's also a bit of noticeable barrel distortion, about 3.3 percent, and it's likely that some of that edge softness is due to a field of focus that's not entirely flat. That level of distortion causes straight lines to noticeably bow outward in images; it can be corrected in software like Lightroom, which includes a profile for the lens for 1-click adjustments.

The story gets better at 35mm. Distortion dips to an inconsequential 0.4 percent and edges are better, but not tack sharp. At f/2.8 the average score across the frame is 2,829 lines, and performance is even aside from the edges, which show just 1,350 lines. But narrowing the aperture improves them; edges hit 1,450 lines at f/4 (the average score jumps to 3.374 lines) and they manage 1,750 lines by the time you get to f/8, with marginal improvement across the rest of the frame.

At 50mm pincushion distortion sets in. The lens shows 1.6 percent, which noticeably causes straight lines to curve inward. Edges are much better; the center-weighted score at f/2.8 is 2,628 lines, and edges approach 1,700 lines. At f/4 they top 2,000 lines, with a 3,150-line average score across the frame. And at 70mm the lens shows exceptionally even performance, even at f/2.8. At that aperture the score is 2,833 lines, a score that holds across the frame. Stopping down to f/4 nets a 3,410-line score, and it tops 3,500 lines at f/5.6. Pincushion distortion at 70mm is minimal, just 0.7 percent.

The Nikon AF-S Nikkor 24-70mm f/2.8G ED is a workhorse for many a photographer, but it's not without issues. Edges are weak at its widest angle, and there's some distortion there as well. Optical performance gets better as you zoom, with the best performance at 70mm. Pros covering events won't settle for anything less than an f/2.8 zoom, and with a little knowledge of how the lens performs weak spots can be worked around. If f/2.8 isn't a necessity, you may want to consider the Sigma 24-105mm F4 DG OS HSM as a budget-friendly alternative; you'll lose a full stop of light and depth of field control, but save some money and acquire a longer zoom range, optical stabilization, and more consistent sharpness.