Sigma 210101 18-35mm F1.8 DC HSM Lens for Canon - Black

Product Information

This is an amazingly sharp lens, even wide open at ƒ/1.8, which is typically not the case with very wide-aperture lenses. At 18mm and ƒ/1.8, the Sigma shows very little corner softness and a good portion of the center and middle of the frame are very sharp indeed. As we've seen time and again, very wide-aperture lenses (> ƒ/2.8) can often show significant corner softness when used at their widest apertures, but the Sigma 18-35 not one of them. In this respect, it beats even many fast prime lenses in its focal length range. This procedure certainly improved overall focus accuracy when shooting at the distances used for microadjustment. However these are fixed by the software, and there's no option to specifically correct any distance between infinity and 0.5m. Unfortunately though, the vast majority of subjects end up somewhere in between, and we found that the lens still had some problems with focus accuracy even when fully programmed as above. Knowing this, we'd probably configure the 'Infinity' position with a bias towards getting the most accurate focus at closer subject distances.

Sigma, 18-35, 1.8, DC, HSM, Art, Canon EF - HDEW CAMERAS

The Canon EOS R5 is, however, smarter than the 5D. The R5 recognizes the Sigma 18-35mm’s crop factor and automatically changes its Cropping/Aspect Ratio setting to “1.6x (crop)”. APS-C lenses automatically enable “1.6x (crop)”. All other options disabled. Unlike a prime lens with a single focal length, the Sigma is variable. You may zoom in-and-out without physically moving your camera setup. This offers greater flexibility, speed and creative control when composing a shot — especially when mounted on a tripod. To find the full-frame, “35mm equivalency” of the APS-C Sigma 18-35mm, you multiply its focal length by crop factor (which is 1.6 for Canon cameras). This translates to an effective 27-53mm focal length range on full-frame cameras. In the fourth sample we've zoomed in to 35mm and placed the sun just outside the frame. The lens does particularly well here at maintaining contrast and shadow detail. Here you can also see the 'Made in Japan' label - not something you'll find on all lenses any more.

Cons:

The HSM (Hyper Sonic Motor) ensures a silent, high-speed AF function. Optimizing AF algorithm, smoother AF is achieved. It also enables full-time manual focusing capability which allows sensible focus adjustment by simply rotating the focus ring. Comparing the 18-35mm on a mid-range APS-C body to the Tamron 24-70mm F2.8 on one of the latest, similarly enthusiast-focused full frame DSLRs, there's essentially no difference in overall bulk. The small differences in weight and and length between the lenses make no appreciable difference to the handling, either. The main difference lies in the 18-35mm's internal zoom design, whereas most 24-70mm F2.8s extend substantially on zooming. Autofocus I tested the sharpness of this lens in a number of situations, and found it to be pretty consistent and sharp at all focal lengths and apertures. Yes, it is most certainly sharpest between f/5.6 and f/7.1, with the best image quality at a wide angle produced at f/2.8. However, it still performs pretty well at f/1.8, just maybe not quite as good as many of us were hoping. It certainly is softer than the 35mm f/1.4, but is markedly better than any other variable focal length kit lens in this range that I have used.

18-35mm F1.8 DC HSM – Sigma UK

We also see well-controlled vignetting with the Sigma 18-35mm lens. While there is still some vignetting at apertures wider than ƒ/4, it's not extreme and the amount of vignetting is consistent across all focal lengths. At all focal lengths, there's about a half to just shy of two-thirds of a stop of light loss. Vignetting decreases notably when you hit ƒ/2.8 with less than or equal to a fourth of a stop of light loss. When stopped down to ƒ/4 and beyond, vignetting at all focal lengths is barely noticeable.

While on that note, the lens is rather large, especially for what many of you will be used to with this focal range. It’s a few inches longer than a comparable Canon 18-55mm or Nikon 18-35mm. The entire zoom range is internal, so it doesn’t change sizes on you. Image quality is next to perfect, bokeh, speed aperture yeah just about everything about this lens is almost perfect. Overall though, this level of chromatic aberration is impressively low, especially considering that we're looking at an ultra-fast zoom. It's no worse than we'd expect to see from fast primes, either. Flare The other take-home message here is that, while our copy of the lens showed a tendency towards focusing in front of subject (and therefore required positive microadjust values), the correction needed at each setting was different. So using a global in-camera microadjust value would necessarily be a compromise - setting a value to correct any given focal length and subject distance could throw off the focus at other settings. We observed this in practice using the Canon EOS 7D's microadjust feature - it could only be set to give optimal focusing at one given focal length and subject distance. Are we looking too closely? A final footnote is that I hear far fewer complaints coming from Nikon and Sony users than I do from Canon shooters. My guess is that Sigma autofocus is probably at its worst on Canon bodies. All third party manufacturers have to reverse engineer autofocus algorithms, but my experience is (at least for Canon) that Tamron has this better figured out than Sigma.

Sigma Art 18-35mm f/1.8 - Canon EF - CVP Sigma Art 18-35mm f/1.8 - Canon EF - CVP

At 35mm F1.8 things are slightly different- if you shoot a flat scene straight-on you'll see a gradual drop-off in sharpness right across the frame. But this mainly due to curvature of field, so if you shoot something three-dimensional then objects in the extreme corners will look sharp if they happen to be in focus. The lens shows practically no chromatic aberration at 35mm, either, which means that the images look very clean indeed. Overall, this kind of image quality is remarkable coming from an F1.8 zoom. Autofocus accuracy and consistency The Sigma 18-35mm f/1.8 is an affordable lens with fantastic “Sigma Art” image quality, sharpness, and performance when shooting video on the Canon EOS R5. Its large aperture is well suited for shooting video in low light environments, its “35mm effective” 27-52mm focal length is just right, and you may capture high quality 4K video without overheating. The R5 is effectively cropping the image for you. That’s more convenient than how the Canon 5D Mark IV functions, but the net result is still a low resolution image (18 megapixels instead of 45, the native resolution of the R5 sensor). When I saw the above, I changed the setting on my Nikon D800E to switch to DX crop mode when the lens was mounted on it. Autofocus Performance and Accuracy

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In conclusion, this is a groundbreaking lens no matter how you look at it, and I applaud Sigma for taking a chance and thinking outside the box. I do feel that it is has paid dividends here. The image quality from the Sigma 18-35mm f/1.8 DC HSM ART lens is exceptional in every facet, and the fact that Sigma managed to go a full 1 1/3 stops wider than other zoom lenses while still nailing the image quality is a huge achievement in engineering. The next review on my list is the brand new full frame 24-35mm f/2 from Sigma. Sigma’s Achilles’s heel of focus accuracy persists with the 18-35mm, but I do think that many people will find the lens good enough to endure a little tweaking to get it right on your body. Pair this lens with a good telephoto and you would have an excellent kit that would offer premium image quality on the great APS-C bodies available to consumers right now. Above all, though, I commend Sigma for taking some chances and swinging for the fences. I’m reminded of the quote from Norman Vincent Peale, “ Reach for the moon. Even if you miss, you’ll land among the stars.“ Pros:

Sigma 210306 18-35mm F1.8 DC HSM Lens for Nikon - Black Sigma 210306 18-35mm F1.8 DC HSM Lens for Nikon - Black

One real problem we had in real-world shooting with the 18-35mm was with autofocus. Depth of field is limited at F1.8 - especially at 35mm - which means that even slight misfocusing can become very visible if you look closely at your images. We shot with a range of Canon SLRs, from the entry-level EOS 100D to the top-of-the-line EOS 7D, and all had problems focusing absolutely correctly all the time. This was usually only obvious when shooting at apertures larger than F2.8. In general, we got slightly better results by using the central AF point (with recomposition) compared to using off-centre AF points, but this didn't eliminate focus errors entirely. Crop” video is higher quality than regular 4K, which is what you get when 4K HQ mode and Movie Cropping are both set to “Disable” (see below). 4K HQ mode disabled on the Canon EOS R5

Vignetting

In terms of design and control layout the lens is decidedly conventional, with a large manual focus ring at the front, a zoom ring placed closer to the camera body, and a distance scale and focus mode switch placed between the two. As usual for this class focusing is internal; less conventionally for a normal zoom, so is zooming, which means that the lens stays the same length at all times. On the camera