Rather a Canon 16-35 mm f/4 IS than a 16-35 mm f/2.8 II?

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A comparison of the new Canon 16-35 mm f/4 IS with the Canon 16-35 mm f/2.8 II that we reviewed previously is obvious. The list price of the Canon 16-35 mm f/4 (1100 euros) is 600 euros more, and the built-in image stabilization – a premier for the Canon L wide-angle lenses – offers more profit than the 1-stop difference in brightness between the two zooms. In terms of dimensions, they’re pretty evenly matched.
Both lenses will be flexibly used for landscape and architectural photography. There, you general don’t need to worry about a fast-moving subject, and the Canon 16-35 mm f/4 IS has the advantage if it’s about making sharp images for you. But is this new Canon L zoom lens even sharper?

Canon 16-35 mm f/4 @ 16mm: Ideal for (city) landscape photography
Build and auto focus
The Canon 16-35 mm f/4 IS L is really solid in construction, including being extra-well sealed against dust and moisture, as we’ve grown accustomed to from Canon L lenses. Both lens elements at the ends are treated with an extra fluorite coating, so that they have extra protection against fingerprints, water droplets and dust. You can use this lens without problems under the most extreme circumstances. On this lens, there are two switches (on/off for AF and IS) and a distance scale. The minimum focal distance amounts to 28 cm. The Ultrasonic AF Motor (USM) ensures fast and precise auto focus and is quiet as well, but a bit less quiet than a Canon STM lens. In addition, with continuous AF focusing, you can focus manually at any time without leaving the AF mode. The length of the lens changes very little during zooming and focusing. The focal arc of this lens is about 90 degrees: more than sufficient to offer precise focusing. When you change the focal distance, you don’t have to focus again, while with other lenses that is sometimes necessary. The front lens does not turn, which is nice if you’re using filters such as circular polarization. The filter size of the Canon 16-35 mm f/4 (77 mm) is one size smaller than that of the Canon 16-35 mm f/2.8 MK2.	{insertgrid ID = 289}
Vignetting
Vignetting with Canon is simple to correct by using the automatic correction for the jpg files that will be saved in the camera. Normally in our reviews, we save the jpg files including in-camera corrections and the RAW files without any in-camera correction. During this review, the lens correction profile was not yet available, so in this review the jpg files also lack in-camera correction. In the review of the Canon 16-35 mm f/2.8 L, we could make use of the in-camera corrections for chromatic aberration and vignetting. The vignetting in jpg files was a bit more visible than in RAW shots, because the jpg files show a higher contrast.
If you want to compare the image quality of this lens with the image quality of the Canon 16-35 mm f/2.8, do so on the basis of the results from the RAW files, even if you photograph in jpg yourself. In a Canon camera, you can install up to 20 different lens correction profiles on your camera with the included Canon Utility software. After the next update of EOS Utility (see the image below), you can select the lens correction profile for this lens and install it on your camera.

Canon 16-35 mm f/4 @ 35mm: a zoom range of a factor of 2 doesn’t seem like much, but with a wide-angle zoom it’s more than sufficient: the zoom range includes the fixed focal lengths of 16, 24, 28, and 35 mm.
Distortion
The distortion runs, as with practically all wide-angle zoom lenses, from visible barrel-shaped distortion at 16 mm to visible pincushion-shaped distortion at 35 mm. If you don’t frame your shots too tightly, then you can correct for distortion with software afterwards if you think that it’s disruptive.
Flare
This lens has very little trouble with flare. Canon’s famous Super Spectra Coatings reduce flare and reflections – even if you photograph directly against the sun, as in the practice shot shown here. With that, the Canon 16-35 mm f/4 IS does a little better than the Canon 16-35 mm f/2.8 II did in our earlier review. If you use a small aperture, then a bright light source, thanks to the 9 lamellae, gives a nice, 18-point star. The included sun cap is a useful aid for protection of the front lens.
Image stabilization Canon 16-35mm f/4 IS
The Canon EF 16-35 mm f/4L IS USM lens has Canon’s Image Stabilizer technology, which automatically detects whether you’re taking normal shots or whether you’re following a moving subject with the camera. The camera switches automatically between the two image stabilization modes. That is a much more elegant solution than a switch with two IS modes on the lens.
We did a lot of shots by hand with and without image stabilization, at a focal distance of 35 mm. We then determined the sharpness of all the shots with Imatest. A picture taken by hand at a focal distance of 35 mm and a shutter speed of 1/45 of a second is as sharp as a picture at the same focal distance and a shutter speed of 1/6 of a second made with image stabilization. In both cases, we reach about 75% of the sharpness of a picture made from a tripod. That is a difference that is barely visible to the naked eye. Thanks to the built-in image stabilization, you make a profit of two stops.
Sharpness
In terms of sharpness, the Canon 16-35 mm f/4 IS gives a better performance than the Canon 16-35 mm f/2.8. Not only is the center sharpness starting from full aperture already (almost) maximum, but the sharpness is also nicely even across the image. The sharpness in the corners increases when you stop down 1 or 2 stops, but even at full aperture the sharpness in the corners looks very good. This is Canon’s best wide-angle zoom when it comes to sharpness.
Click on the image to the right for a partial enlargement of the area in the box. When you compare a picture made at f/8 with a picture made at f/4, then you see that the sharpness at the edges increases a bit with stopping down. If you only looked at a picture made at f/4, then you would probably be satisfied with the sharpness. The difference in sharpness at the edges, in particular the red leaves, looks richer in contrast, but is only noticeable in a direct comparison.
Chromatic aberration
The lens design consists of 16 elements in 12 groups. That’s a pretty complex design, making the chance of color deviations higher. In order to prevent or correct as many aberrations as possible, there are 3 “glass molded” aspherical lens elements and 2 elements with special, high-quality (UD: (Ultra Low Dispersion)) glass applied. That hit the mark. Both longitudinal chromatic aberration (color bokeh in the whole image) and lateral chromatic aberration (red and blue edges at sharp contrast transitions in the corners) are well controlled.
Bokeh
A round aperture with 9 lamellae, according the information from Canon, ensures a nice, round bokeh, so that your subjects in the foreground stand out from the blurred background. In terms of bokeh, the Canon 16-35 mm f/4 gives nothing up to the brighter Canon 16-35 mm f/2.8, which has an aperture with 7 lamellae. As we often see with wide-angle zoom lenses, the bokeh does show rings in some situations, such as you can see in the partial enlargement of a practice shot shown here. Our standard bokeh test set-up delivered – for a wide-angle zoom – a great bokeh. (Move your mouse over the image.)
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Conclusion Canon 16-35mm 4 IS test with Canon 5D MK3
	Look in our list of all reviewed lenses or the lenses we have reviewed with a Canon mount in order to compare the performance of this lens with other lenses.
WYSIWYG score: This table displays the performance of this lens if you save the files in the camera as jpg with all available in-camera lens corrections applied. This score gives you for this lens/test camera combination: “What you see is what you get”.	{insertgrid ID = 308}
Pure RAW score: This table displays the performance of this lens if the file is saved in the camera in RAW format. This score approaches the intrinsic quality of the combination of lens and test camera.	{insertgrid ID = 309}
Pros Exceptional wide-angle zoom range for a full-format camera Superior image quality Beautiful, even sharpness across the whole image Built-in image stabilization Water and dust resistant	Cons Quality has its price Visible distortion and vignetting
Some documentary photographers might prefer a Canon 16-35 mm f/2.8 L because they regularly photograph moving subjects in the dark. But the majority of the architecture, documentary and landscape photographers who want to head out with a wide-angle zoom lens of unusually high quality will, on the basis of the built-in image stabilization and the higher image quality, prefer the Canon 16-35 mm f/4L IS above the Canon 16-35 mm f/2.8 L. {insertgrid ID = 600}