Review Sigma 18-200 mm C @ Nikon
Will it be a Sigma 18-250 mm or a Sigma 18-200 mm Contemporary?
The Sigma 18-200 mm Contemporary is smaller, lighter and less expensive that its cohorts, such as for example the Canon 18-200 mm. In addition, in contrast to similar superzooms that we have reviewed so far, Sigma 18-250 mm, Tamron 18-270 mm and the Nikon 18-200 mm, the Sigma 18-200 mm C wins in terms of compactness, weight and list price. Those are important considerations for the target audience, amateur photographers who want to have a not-too-expensive all-around lens with a strong zoom range, in order to head out without having to haul along too much weight and without having to change lenses. Our first positive experiences with the Sigma 18-200 mm on a Canon 650D we previously published. Because we did not review the Sigma 18-250 mm on a Canon APS-C, we could not make a direct comparison of the image quality of both Sigma walk-around zooms. Now we can.
|At the smallest focal distance, you get a nice amount in the frame, although you get some distortion in the bargain.|
Build and auto focus Sigma 18-200 mm Contemporary
First of all, what's noticeable is how compact this zoom lens is: shorter, smaller and much lighter (30%) than the Nikon 18-200 mm. In comparison with the old version of the Nikon 18-55 mm kit lens, the Sigma 18-200 mm C is only 6 mm (!) longer and 1 mm broader, while the zoom range is 3.5x as large. The Sigma 18-200 mm housing is made of a light and sturdy composite material, with a metal mount. Just like all superzooms, this lens becomes more than twice as long when you set it to the longest focal distance and use the included sun cap. On the lens, there are three slide switches: AF vs manual focusing, on/off for the image stabilization and in order to block the zoom during transport. The focusing ring has a relatively short run, meaning that you can quickly focus manually. On the other hand, that also makes it harder to manually focus with precision. Because superzooms do not have a large aperture, that's not really bad. The Hyper Sonic Motor (HSM) ensures fast, silent AF. Where you can manually override the HSM motor at any time desired, that's not possible with this lens. With this one, you have to flip the AF/MF switch.
|It's nice that the Sigma 18-200 mm Contemporary is equipped with built-in image stabilization. Built-in image stabilization ('OS') ensures that you can photograph by hand longer, without having to set higher ISO values on the camera in order to prevent motion blur.
We previously reviewed the image stabilization of the Sigma 18-200 mm on a Canon 650D at a focal distance of 46 mm. If you photograph by hand, then the resolution begins to drop off from 1/50 of a second. Shots made with image stabilization, but at a shutter speed of 1/13 of a second appear to be sharper. The built-in image stabilization delivers a profit of 2 to 3 stops. That's impressive.
Vignetting Sigma 18-200 mm Contemporary
Vignetting is nicely kept in check for a zoomlens with such a large zoom range. At full aperture, vignetting will be visible in some situations, but if you use a smaller aperture, so that the sharpness also increases, then in practice you won't have any trouble with vignetting.
Click (2x) on the image for a larger version..
At the longest focal distance, it's possible to isolate the subject from a possibly restless background.
The course of distortion is typical for a superzoom and runs from visible barrel-shaped distortion at 18 mm to pinchushion-shaped distortion at focal distances above 30 mm. In particular, the barrel-shaped distortion at the shortest focal distance is sometimes clear to see. Distortion for RAW files is simple ("with one press of a button") to automatically correct with the lens correction profiles in Lightroom or Photoshop.
|Below, you see an illustration of the worst-case distortion (at 18 mm) and the effect of correction in Lightroom (move your mouse over the image below and pay attention to the pole on the right-hand side). If you don't photograph in RAW, then DxO Optics Pro can offer a solution where there are also lots of lens correction profiles available for jpg files.
And if you don't have these programs available: because the distortion between 28 mm and 200 mm is so constant, you can apply the same correction across the entire zoom range.
The Sigma 18-200 mm is delivered standard with a sun cap, but you don't generally have to use it for backlight. It sporadically occurs that internal reflections arise, such as in the partial enlargement of a Sigma 18-200 mm Contemporary practice shot shown here.
Sharpness: zoom or megazoom?
Some people expect a megazoom to have the same image quality as much more expensive lenses with a fixed focal length or as many more expensive, bright zoomlenses. That is not realistic. The current megazooms deliver an acceptable image quality across the whole zoom range, which is better than what you get with a compact camera. The center sharpness is often surprisingly high, but the edges and certainly the sharpness in the corners for superzooms is less. Partially, but not completely, that's correctable by stopping down 1 or 2 stops. That also applies for the Sigma 18-200 mm C.
The center sharpness at 18 mm is already good starting at full aperture and that increases even more after stopping down 1 stop. After stopping down 2 stops, the corner sharpness is nicely close to the center sharpness. That doesn't apply for the longer focal distances, where the sharpness in the corners lags behind the center sharpness. In the range of 20 to 90 mm, the Sigma 18-250 mm (where the corners improve with stopping down) appears to perform somewhat better; at 200 mm, the Sigma 18-200 mm seems to do it better. In the whole, it's an even match between the Sigma 18-250 mm and the Sigma 18-200 mm C, when it comes to sharpness.
Sigma 18-200 mm C @ 200mm, 400 ISO, 1/4000 sec, f/6.3 (detail)
Chromatic aberration Sigma 18-200 mm Contemporary
|With lateral chromatic aberration, not all colors come out in exactly the same place in the corners of the image, so that you can find blue and red edges at sharp contrast transitions in the corners. The Nikon D7100 corrects for this outstandingly, so that you don't encounter any visible chromatic aberration in the jpg files. In the RAW files, chromatic aberration, just as with all other superzooms, is visibly present. That's simple to correct with software.
The Sigma 18-200 mm Contemporary is also very suitable for close-up photography. And that makes the lens extra versatile. The shortest focal distance amounts to just 39 cm, which delivers an image scale of 1:0.33. Sigma makes that known by using the "macro" label in the not-short name: Sigma 18-200 mm F3.5-6.3 DC Macro OS HSM C. It's not real macro; for that we adhere to the definition that the image on the sensor is the same size as the original (image scale 1:1).
All superzooms have a less woolly background blur. And the Sigma 18-100 mm C is no exception to that. At the longest focal distance, the focal depth is so small and the bokeh is nice enough in order to beautifully isolate the subject from the background, as you can see in the partial enlargement below from a practice shot made on the Nikon D7100.
Conclusion Sigma 18-200 mm Contemporary review with Nikon D7100
WYSIWYG score: This table shows the performance of this lens if you save the files in the camera as jpg, so that chromatic aberration is corrected by the Nikon D7100. This score gives you for this lens/test camera combination: "What you see is what you get".