I am finally back in Denver after a three week-long trip to the UK and I am trying to catch up with all the news and announcements that we’ve missed. The first news items are related to Canon lens announcements from last week. Canon announced the EF 16-35mm f/4L IS USM image-stabilized full-frame lens for enthusiasts and professionals who want something cheaper than the EF 16-35mm f/2.8L II USM. Usually, f/4 lenses are lighter and smaller than their f/2.8 counterparts. However, the difference between the 16-35mm f/4L and 16-35mm f/2.8L is not as big – the former is just a tad thinner and weighs 20 grams lighter in comparison. The three biggest differences are obviously the smaller maximum aperture of f/4, $500 price difference and image stabilization. With a very similar optical design featuring the same number of elements and groups, 2 Ultra-low Dispersion (UD) and 3 Aspherical elements, the 16-35mm f/4L IS seems to challenge its big brother in a number of ways, even in optical performance.
If you take a look at the MTF graphs of both lenses, the Canon 16-35mm f/4L IS appears to be sharper and more consistent optically at f/4 than the 16-35mm f/2.8L II at f/2.8. Take a look at the MTF charts below comparing the two at 16mm (Left: 16-35mm f/4L, Right: 16-35mm f/2.8L II):
And here is the comparison at 35mm:
As you can see, the performance differences are clear – the 16-35mm f/4L is certainly sharper. However, this does not mean that it is better than the 16-35mm f/2.8L II stopped down to f/4. Since Canon does not provide MTF charts for stopped down performance across the aperture range, only lab tests would reveal how the two compare side by side at f/4. My guess is, since the 16-35mm f/4L is a newer design, both will be very similar. Stopped down to f/8, the MTF chart shows the new 16-35mm f/4L to be superior at both 16mm and 35mm focal lengths. This gives a good advantage to the 16-35mm f/4L, since it is cheaper and has image stabilization, as already mentioned above.
Those who do not already own the 16-35mm f/2.8L II might want to take a close look at the new f/4L IS version. Since such wide focal lengths are not used for portraiture, the maximum aperture of f/2.8 does not matter, especially when the f/4 version comes with image stabilization that is supposed to provide up to 4 stops of shutter speed advantage.
Here is the information from the official press release:
Fully compatible with all EOS Digital SLR cameras including full-frame models like the EOS 5D Mark III and EOS 6D Digital SLR cameras, the compact and lightweight EF 16-35mm f/4L IS USM ultra wide-angle zoom lens offers high image quality and an Optical Image Stabilizer (IS) for shake correction up to four shutter speed steps, making handheld shooting possible in dimly lit scenes where camera shake can occur. In addition, an intelligent CPU in the lens automatically selects the optimal IS mode by recognizing differences between normal handheld shots and panning. This technological advancement supports a greater range of creative expression for photographers in otherwise difficult shooting situations, such as dark indoor scenes where flash photography is prohibited, or in places where a tripod cannot be used, or when shooting at low ISO speeds.
The EF 16-35mm f/4L IS USM ultra wide-angle zoom lens features newly developed, high quality Canon optics that incorporate three GMo (Glass-Molded) aspheric lens elements, including a large-diameter aspheric lens, which help improve image quality by correcting aberrations. Two additional UD lens elements help reduce chromatic aberration from edge to edge throughout the entire zoom range for excellent image quality with high resolution and contrast. The lens also features enhanced fluorine lens coatings on the front and rear lens surfaces to repel dust particles and help ensure superb color balance while minimizing ghosting. The inner focusing and ring USM offer silent, fast and accurate autofocusing. Full-time manual focus adjustment is available in autofocus (AF) mode. A nine-blade circular aperture creates beautiful, soft backgrounds. A new compact four-group zoom system provides a minimum focusing distance of 0.28m/11 inches throughout the zoom range and a maximum magnification of 0.23x at the telephoto end for outstanding performance.