Nikon AF-S 28-70 mm f/2.8D vs. Nikon AF-S 24-70 mm f/2.8G
Since 2008, I've been working with a Nikon D3 camera. Its sensor is twice as large as the sensors of previous Nikon cameras (like the Nikon D1, D1H, D1X, D2X, D2Xs, D2H, D2Hs, D70, D70s, D80, D100, D200, D300). During the first few weeks I've checked the performance of my current lenses on the Nikon D3. On the previous Nikon cameras with the smaller sensor (called "DX sensor"), my workhorse has been the Nikon AF-S 17-35mm f/2.8D lens. I've used it for landscape work, for travelling, for PJ work and sometimes even for concerts to show the whole scene. It's safe to say, the Nikon AF-S 17-35mm f/2.8D lens has been one of the most valuable lenses in my collection. I've sometimes tried to go wider (e.g. with the Nikon AF-S 12-24mm f/4G DX lens), but I've always returned to the 17-35mm lens because of its optical quality and because of the lower geometrical distortion (in my opinion, it's not easy to put ultra-wide lenses to good use).
On the Nikon D3 with its larger sensor (called "FX" or "full frame sensor"), the Nikon AF-S 17-35mm f/2.8D is a lot wider. It serves a different purpose on the larger sensor. On the Nikon D3, a 25.5mm-52.5mm lens is needed to cover the same as a 17-35mm lens on a DX camera. There are two professional Nikon lenses which more or less cover this: The Nikon AF-S 28-70mm f/2.8D and the Nikon AF-S 24-70mm f/2.8G N. I've already owned the first one for several years. During the first few weeks with the Nikon D3 I've noticed quite some vignetting and edge softness with the Nikon AF-S 28-70mm f/2.8D lens. Since this lens now covers a very important focal length (in fact, the most important focal length for me), I've looked for alternatives. A friend of mine, Michael Sengers, www.sengers.ch kindly offered me his brand new Nikon AF-S 24-70mm f/2.8G N lens for a day of testing. Below, you can find some of the results of my testing. To make it short: I fell in love with the Nikon AF-S 24-70mm f/2.8G N during the first hour of testing and after close examination of a few hundred test images (done with both pro lenses mentioned) I've sold the Nikon AF-S 28-70mm f/2.8D lens and ordered the Nikon AF-S 24-70mm f/2.8G N lens. It turned out to be an excellent investment: The Nikon AF-S 24-70mm f/2.8G N lens has become my workhorse lens on the Nikon D3. It's even sharper and more versatile than the Nikon AF-S 17-35mm f/2.8D lens was on my cameras with DX sensors.
Sharpness and Contrast
In my comparisons, the new Nikon AF-S 24-70mm f/2.8G N lens proved to be sharper than the older Nikon AF-S 28-70mm f/2.8D both at the image center and at the edges, especially when used wide open. Sharpness was tested with the camera on tripod and with cable release and mirror lock-up. Proper focus was achieved by using the camera's live view at the highest magnification (manual focusing). Center and edge performance is compared at 28 mm. At 70 mm only center sharpness is tested. Have a look at the following links:
Sharpness at 28 mm (24-70mm vs. 28-70mm lens)
Sharpness at 70 mm (24-70mm vs. 28-70mm lens)
The same target (a train station building) was used for both center and edge performance (re-framing, re-focusing). The building is far away so the performance at long distance is analyzed. This makes sense since the Nikon AF-S 24-70 mm f/2.8G and Nikon AF-S 28-70 mm f/2.8D are good lenses for landscapes on a full frame camera.
In real-world situations the sharpness differences might be smaller. The images were taken in late afternoon, so the color temperature changed during the test. The Nikon AF-S 24-70 mm f/2.8G lens shows more sharpness at f/2.8 and 28 mm at the outer edge. In center, both lenses show a similiar performance. At f/5.6 and above there is almost no difference between the lenses (center and edge). At 70 mm, the new lens shows more sharpness at f/2.8 even in the center. At f/4 both lenses are close in performance. The newer lens shows slightly more contrast over the whole image and warmer overall colors throughout all focal lengths and apertures. Below, you have access to full resolution images (they are not the same as the ones in the links above) to analyze the differences for yourself. The differences can be seen best when a good monitor is used and when the images are opened in Photoshop or any other program with color managment.
Full resolution sample (at 28 mm f/2.8) (Nikon AF-S 24-70mm f/2.8G)
Full resolution sample (at 28 mm f/2.8) (Nikon AF-S 28-70mm f/2.8D)
Full resolution sample (at 28 mm f/5.6) (Nikon AF-S 24-70mm f/2.8G)
Full resolution sample (at 28 mm f/5.6) (Nikon AF-S 28-70mm f/2.8D)
Move around the images at 100% and look at trees at the outer parts of the images. The difference is bigger than the crops in the first comparison suggest. I've decided to buy the new lens since the focal range between 24mm and 70mm is very important to me. Good corner sharpness is vital for landscape shots and decent sharpness when used wide open is important for a lot of other work (mostly PJ work in low light).
In addition, the new lens offers more wide angle
(24mm instead of 28mm) which really does make a difference. You can see this in the following comparison:
24 mm vs. 28 mm (24-70mm vs. 28-70mm lens)
Well, 24mm vs. 28mm don't make the image more interesting in this case, but you get the idea. Also take into consideration that the 24mm setting on a Nikon D3 even offers slightly more wide angle than a 17mm lens offers on a DX camera. Besides, the new lens focuses on smaller distances. A comparison of the minimum focus distance of both lenses can be seen here:
Closest focusing (at 70 mm) (24-70mm vs. 28-70mm lens)
This is an advantage for full frame sensors with their wider field of view (even though, for close-ups at f/2.8, images are rather soft with both lenses).
Vignetting is a fact of life with full frame cameras. People who don't agree have either forgotten about it (those who have used film SLR cameras) or never experienced it (the digital generation). Just pick up a film SLR camera like the Nikon F801s and see how much vignetting there is with this camera and most lenses. You can see it clearly when looking through the viewfinder. Cameras with DX sensors use the center of the lens and don't cover the outer edge. Vignetting is almost invisible on such cameras. After using DSLR cameras with DX sensors for 5 years I've simply forgotten about vignetting.
First, let's take a look at the vignetting of the Nikon AF-S 28-70 mm f/2.8D lens in combination with the Nikon D3 full frame camera. The following images show a part of the sky at different apertures (images taken on tripod, showing the same part of the sky). The images demonstrate the effect of filters and lens hoods. Follow the links below:
Vignetting at 28 mm (Nikon AF-S 28-70mm f/2.8D)
Vignetting at 70 mm (Nikon AF-S 28-70mm f/2.8D)
As you can see, filter and hood have almost no impact on vignetting. Vignetting is stronger towards the long end (70 mm) but is nothing to really worry about even at f/2.8. Keep in mind that zoom lenses generally show more vignetting than prime lenses. In real-world situations vignetting can appear stronger than shown in my images (when images with lots of sky are underexposed) or weaker (when images don't contain much sky / areas with uniform brightness).
How does the new Nikon AF-S 24-70 mm f/2.8G lens compare to the older classical Nikon AF-S 28-70 mm f/2.8D lens? I've tested vignetting on a Nikon D3 without any filters or lens hoods. This time it wasn't perfectly clear but the test should be valid.
Vignetting at 28 mm (24-70mm vs. 28-70mm lens)
Vignetting at 70 mm (24-70mm vs. 28-70mm lens)
As can be seen, there is almost no difference between the two lenses. So you don't win much by using the new lens when vignetting is an annoyance to you.