Sigma 18-35mm F1.8 DC HSM Review

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1 Source: QUICK LINKS: Videos Sample Images Camera Timeline Link Directory News Reviews Buying Guide Sample Images Articles Cameras Lenses Phones Printers Software Forums Galleries Challenges 1. Introduction Sigma 18-35mm F1.8 DC HSM Review September 2013 By Andy Westlake and Richard Butler Search on dpreview.com Like 588 Tweet Log in to dpreview Not a member? Register Pages Review based on a production Sigma 18-35mm F1.8 DC HSM Sigma has a long history as a lens maker, having been founded over 50 years ago. In the film era it was best known for relatively inexpensive lenses that undercut the camera makers' own equivalents in terms of price. But this has changed over the part decade or so; while other companies have shifted manufacturing to cheaper locations such as China and Thailand, Sigma has stubbornly refused to move from its factory in Aizu, Japan. This means it can no longer compete in the same way on price alone, and it's therefore switched its focus towards higher-value offerings. Introduction Design and... Test results Over the past few years we've seen increasingly ambitious concepts appear from the company's design studios. The original (and recently-replaced) 30mm F1.4 EX DC HSM has long been one of our favourite lenses for APS-C SLRs, and the 50mm F1.4 EX DG HSM grabbed our attention back in 2008 due to its sharpness at large apertures. Most recently the 35mm F1.4 DG HSM impressed us with its exceptional optical quality at a very competitive price. This all bodes well for the company's latest offering - the record-breaking 18-35mm F1.8 DC HSM, which is the first constant F1.8 SLR zoom lens to hit the market. Sigma's choice of F1.8 as maximum aperture isn't a coincidence; it means that the lens will offer the same control over depth of field as an F2.8 zoom does on full frame. What's more, it will also offer effectively the same light-gathering capability as an F2.8 lens on full frame. By this we mean that it will be able to project an image that's just over twice as bright onto a sensor that's slightly less than half the area, meaning the same total amount of light is used to capture the image. This is important as it's a major determinant of image quality. Essentially it means that APS-C shooters will be able to use lower ISOs when shooting wide open in low light and get similar levels of image noise, substantially negating one of the key advantages of switching to full frame. As we'd expect at this level, the lens uses an ultrasonic autofocus motor for fast, silent focusing. It's compatible with Sigma's new USB dock which allows you to fine-tune autofocus behaviour in much more detail than the AF microadjust corrections found on SLRs, which should help get the best possible focus accuracy and make the most of the large aperture. It also incorporates several of the thoughtful design touches that we were impressed by on the 35mm F1.4, including an improved AF switch, and a large grip area on the base of the barrel for better handling. The lens's 27-53mm equivalent focal length range is obviously a little limited, but should still be rather useful for such applications as wedding and events photography. So while it may not quite match the capabilities of a 24-70mm F2.8 on a full frame SLR, for existing APS-C users it should offer something very close. Crucially, at a street price of around $800 / 650 at the time of writing, for existing APS-C shooters it's an awful lot cheaper than buying a 24-70mm F2.8 and a full frame SLR to go with it. Overall the 18-35mm F1.8 is a really intriguing product, and we applaud Sigma for pushing the boundaries of lens design ahead of the more conservative camera manufacturers. But can an F1.8 zoom really deliver good results? Let's find out. Test results Overall... Conclusion... Preview... Latest reviews Sony Alpha A3000 Sigma 18-35mm F1.8 DC HSM Sep 2, %

2 Headline features 18-35mm focal length (approx 28-50mm equivalent) Extremely fast F1.8 maximum aperture Ring-type ultrasonic focus motor with full-time manual override Initially available in Canon EF, Nikon F and Sigma SA mounts; Pentax K and Sony Alpha to follow Angle of view The pictures below illustrate the focal length range from wide to telephoto (on Canon APS-C, 1.6x). The 18-35mm covers a modest 2x zoom range. Aug 26, 2013 Canon EOS 70D Aug 15, 2013 Sigma USB Dock quick review Aug 12, Waterproof Group Test Aug 9, mm (29mm equivalent) Sigma 18-35mm F1.8 DC HSM specifications Date introduced April 2013 Street Price (August 2013) $800 (US) 650 (UK) 850 (EU) Maximum format size APS-C Focal length 18-35mm 35mm equivalent focal length (APS-C) 27-53mm (1.5x) 29-56mm (Canon 1.6x) Diagonal angle of view Maximum aperture F1.8 35mm (56mm equivalent) Minimum aperture F16 Lens Construction 17 elements in 12 groups 5 SLD glass elements 4 glassmold aspherical elements Number of diaphragm blades 9, rounded Minimum focus 0.28m / 0.92ft Maximum magnification 0.23x AF motor type Ring-type Ultrasonic Motor Full time manual focus Focus method Internal Zoom method Rotary, internal Image stabilization No Filter thread 72mm Does not rotate on focus Supplied accessories* Front and rear caps Lens hood LH Weight 810g (28.6 oz) Dimensions 78mm diameter x 121mm length (3.1 x 4.8 in) Lens Mount Canon EF, Nikon F, Pentax K, Sigma SA, Sony A Latest news This week Pentax Q7 Aug 8, % Sigma 17-70mm F2.8-4 DC MACRO OS HSM C Aug 5, % See more... DxO Optics Pro adds support for five recent cameras Olympus fraud saga rumbles on with UK prosecution Microsoft to acquire Nokia's smartphone business DxOMark tests Canon EOS 70D sensor and lenses Back to the future: ten one-of-a-kind cameras from the 21st century Need the speed? Sigma 18-35mm F1.8 DC HSM in-depth review Ilford opens US lab to meet demand for black and white film development Goldfish all gone? Turn that empty tank into an underwater housing Black-and-white images capture the power of summer storms Last week Billboards offer tourists a glimpse of smog-free Hong Kong * Supplied accessories may differ in each country or area If you're new to digital photography you may wish to read the Digital Photography Glossary before diving into this article (it may help you understand some of the terms used). This article is Copyright 2013 and may NOT in part or in whole be reproduced in any electronic or printed medium without prior permission from the author. 1. Introduction Editorial content Camera reviews Lens reviews Printer reviews Previews Sample images Articles Glossary Product database Cameras Lenses Printers Software Smartphones Camera search Camera comparison Community Forums Challenges Galleries Polls My Profile My Settings My GearList Connect with dpreview Subscribe to the weekly newsletter

3 QUICK LINKS: Videos Sample Images Camera Timeline Link Directory News Reviews Buying Guide Sample Images Articles Cameras Lenses Phones Printers Software Forums Galleries Challenges 2. Design and Operation Search on dpreview.com Design Log in to dpreview Not a member? Register The 18-35mm follows in the same design idiom as Sigma's most recent lenses such as the 35mm F1.4 DG HSM. The section of the barrel between the mount and the zoom ring is metal, and the central section is composed of Sigma's 'Thermally Stable Composite' in an attempt to balance strength and weight. Rubber grips on the focus and zoom rings, combined with a high level of fit and finish, bring a sense of quality to proceedings. As always, on Sigma lenses, the mount itself is plated brass. 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. Pages On the camera Introduction Design and... Test results There's no denying that the 18-35mm is a pretty large lens - it's 10mm longer than the Tamron 24-70mm F2.8. It's also a fairly heavy lens - essentially the same weight as the more rangey Tamron. However it balances pretty well on high-end SLRs such the Canon EOS 7D shown left, helped by the camera's substantial hand grip. We suspect it's likely to be found on this class of camera most of the time. Test results Overall... Conclusion... On smaller, lighter entry-level SLRs such as the Canon EOS 650D, the overall balance becomes more front-

4 heavy, meaning you'll often find yourself supporting the camera by cradling the lens itself. Frankly, these models tend not to have hand-grips that are comfortable to hold for long periods anyway, so this encouragement to support the lens is no bad thing. Size compared Preview... For a better idea of its size, here's the 18-35mm lined up alongside Sigma's 17-50mm F2.8 EX DC OS HSM and the recent Tamron SP 24-70mm F/2.8 Di VC USD. It's the narrowest in diameter but longest of the three, and weights almost as much as the full-frame Tamron. Against the slower Sigma, the 18-35mm is considerably longer, and weighs 40% more. However, its more substantial build makes it more akin to the aged Nikon AF-S DX Nikkor 17-55mm f/2.8g, compared to which it's only 1cm / 0.4" longer, and 7% heavier. Latest reviews Sigma 18-35mm F1.8 DC HSM Sep 2, % Sony Alpha A3000 Aug 26, 2013 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 The 18-35mm uses Sigma's 'Hypersonic Motor' for autofocus, which is fast, essentially silent, and generally very decisive. The focus can be adjusted manually when the lens is set to AF without fear of damaging its innards. Our sample showed no obvious problem with systematic front- or back-focusing, but we did have some problems with focus consistency when shooting at large apertures (described later in the review). The 18-35mm also works pretty well for live view autofocus, although this is highly dependent upon the camera being used. In video mode, it's not too bad either, indeed probably one of the better SLR lenses we've used. But if you use autofocus during movie recording in a quiet situation, the camera's built-in microphone will be liable to pick up the ticking of the lens's AF motor on your soundtrack. Lens body elements The lens is initially available in Canon, Nikon and Sigma mounts, as tends to be the case from Sigma. Sony and Pentax models will appear later. Our review sample was in Canon EF mount. Unlike Canon's own EF-S lenses it will physically mount on full frame SLRs, but will show substantial vignetting at all focal lengths. Canon EOS 70D Aug 15, 2013 Sigma USB Dock quick review Aug 12, Waterproof Group Test Aug 9, 2013 Pentax Q7 Aug 8, % Sigma 17-70mm F2.8-4 DC MACRO OS HSM C Aug 5, % See more... The filter thread is 72mm, and doesn't rotate on focusing. It's surrounded by a bayonet mount for the petal-type lens Latest news This week Mobile madness? Our opinion on Sony's QX clipon cameras

5 hood. The manual focus ring feels beautifully smooth, and rotates about 110 degrees from infinity to closest focus. The finelyridged rubber grip is about 26mm wide. Sony reveals QX10 and QX100 camera modules for smartphones DxO Optics Pro adds support for five recent cameras Olympus fraud saga rumbles on with UK prosecution Microsoft to acquire Nokia's smartphone business DxOMark tests Canon EOS 70D sensor and lenses Back to the future: ten one-of-a-kind cameras from the 21st century Need the speed? Sigma 18-35mm F1.8 DC HSM in-depth review Ilford opens US lab to meet demand for black and white film development Goldfish all gone? Turn that empty tank into an underwater housing The 21mm-wide zoom ring has a pleasant, fluid movement. It glides smoothly without any play and feels correctly damped, giving a real impression of quality. It rotates 50 degrees from 18 to 35mm, with additional markings at the 20, 24 and 28mm positions. A large switch on the side of the lens barrel sets the focus mode. Like on the 35mm F1.4 DG HSM, when it's set to autofocus (as here) the inlay behind it is white; when switched across to MF the inlay is black. This allows an easy visual check of its position even in low light. Here you can also see the 'Made in Japan' label - not something you'll find on all lenses any more. The bayonet-mount hood is provided as standard, and clicks positively into place on the front of the lens. It's made from thick plastic, and features ribbed moldings on the inside to minimize reflections of stray light into the lens. Sigma has even added a ribbed grip to make it easier to remove. A broad ridged grip covers most of the underside of the barrel between the zoom and focus rings, and provides positive handling when changing lenses.

6 USB Dock compatibility The 18-35mm is compatible with Sigma's unique USB dock, a relatively inexpensive accessory ( 40 / $59 / 60) which allows you to hook Sigma's latest lenses up to a computer - click here to read our quick review. Using the Sigma Optimization Pro software you can then apply detailed autofocus microadjustments if you find your lens consistently mis-focuses on your camera (which can be something of an occupational hazard for SLR users). There's also an option to update the lens's firmware, if it should become necessary in the future. Sigma's USB Dock and Optimization Pro software lets you set AF microadjustments for four focal lengths each at four different focus distances. In principle this allows you to calibrate the lens's focusing specifically for your camera, and help you get the best possible results. Unfortunately, though, the software comes with limited documentation, and specifically no instructions on how you might set about determining the microadjustment values you need to set. So we wonder how many users will really be able to make the most of it. 2. Design and Operation Editorial content Camera reviews Lens reviews Printer reviews Previews Sample images Articles Glossary Link directory Videos Product database Cameras Lenses Printers Software Smartphones Camera search Camera comparison Lens search Product timeline Browse all products Community Forums Challenges Galleries Polls My Profile My Settings My GearList Connect with dpreview Subscribe to the weekly newsletter About us Write for us Advertise with us FAQ Feedback Interest-Based Ads Privacy Legal All content, design, and layout are Copyright Digital Photography Review All Rights Reserved. Reproduction in whole or part in any form or medium without specific written permission is prohibited. Mobile site

7 QUICK LINKS: Videos Sample Images Camera Timeline Link Directory News Reviews Buying Guide Sample Images Articles Cameras Lenses Phones Printers Software Forums Galleries Challenges 3. Test results Search on dpreview.com Studio Tests The Sigma 18-35mm F1.8 DC HSM turns in an exceptional performance in our studio tests, in essence matching a selection of high quality primes. It's remarkably sharp, even wide open, and both chromatic aberration and vignetting are relatively low. Distortion is kept pretty well under control too. Overall this is very, very impressive indeed. Sigma 18-35mm F1.8 DC HSM on Canon EOS 7D Lens review studio test data Click here to compare this lens with others in a new window. Sharpness/CA Vignetting Distortion Test data provided by DxOMark Log in to dpreview Not a member? Register Focal length: Options: Show graphs Aperture: Pages Focal length: 18mm Aperture: f/1.8 Measured focal length: mm Maximum transmission: T/ mm: T/1.8 View full lens data on DxOMark help fullscreen compare Sharpness Chromatic Aberration Vignetting The 18-35mm is remarkably sharp even wide open at F1.8, and in the wider half of its range (18-24mm), there's no measurable increase on stopping down (i.e. the lens is effectively diffraction limited). At the longer end (28-35mm) there's a slight improvement in sharpness on stopping down to F4, but in practice it's unlikely to be especially noticeable. For an F1.8 zoom, this is little short of astonishing. Lateral chromatic aberration is pretty low. The graphs indicate a little green/magenta fringing at wideangle, and moderately strong blue/yellow fringing in the middle of the range (note though that this tends to be visually less intrusive). At the long end, chromatic aberration is essentially nonexistent. Vignetting is remarkably low for such a fast lens, reaching just 1.3 stops wide open at all focal lengths. It also essentially disappears by F2.8. Overall it's unlikely ever to be problematic in real-world use. Introduction Design and... Test results Test results Overall... Conclusion...

8 Distortion Distortion is kept reasonably well under control - it certainly doesn't exceed what we'd expect for this kind of lens. There's visible barrel distortion at wideangle, turning to pincushion distortion at the long end, but no more than you'd get from any other premium standard zoom. Lens test data compared To get a bit more perspective on just how good the 18-35mm is, let's compare it to a couple of benchmark lenses, using the comparison tool in our lens data widget. Click on the images below to open side-by-side comparisons in a new window or tab. Preview... Compared to Sigma 35mm F1.4 DG HSM Latest reviews The Sigma 35mm F1.4 DG HSM impressed us hugely when we reviewed it at the end of last year, and is probably the sharpest 35mm F1.4 prime on the market. When tested on the same camera, the zoom may be just fractionally less sharp at large apertures, but you probably wouldn't see any difference in real world shooting. The zoom also has slightly higher vignetting and distortion, but lower chromatic aberration. From this data, you'd be hard pushed to see any meaningful differences between the two in side-by-side shooting. Remember this is the 18-35mm's weakest focal length. Compared to Tamron 24-70mm F2.8 Di VC USD Sigma 18-35mm F1.8 DC HSM Sep 2, % Sony Alpha A3000 Aug 26, 2013 Canon EOS 70D Aug 15, 2013 Sigma USB Dock quick review Aug 12, Waterproof Group Test Aug 9, 2013 The Tamron 24-70mm F2.8 Di VC USD is probably the best value fast 'normal' zoom for full frame cameras, and like the Sigma 35mm F1.4, we had no hesitation in awarding it a Gold Award in our recent review. Not only does it offer built-in image stabilization, optically it comes as near as makes no difference to its Canon and Nikon counterparts, which are both much more expensive. These lenses can be compared in several different ways, but its clear that regardless of whether we look at them them both tested on the same camera body, or at how the Sigma on APS-C compares to the Tamron on full frame, the 18-35mm easily holds its own in these studio tests. Compared to Canon EF-S 17-55mm f/2.8 IS USM Pentax Q7 Aug 8, % Sigma 17-70mm F2.8-4 DC MACRO OS HSM C Aug 5, % See more... Latest news This week Mobile madness? Our opinion on Sony's QX clipon cameras

9 Sony reveals QX10 and QX100 camera modules for smartphones DxO Optics Pro adds support for five recent cameras Olympus fraud saga rumbles on with UK prosecution Microsoft to acquire Nokia's smartphone business DxOMark tests Canon EOS 70D sensor and lenses Back to the future: ten one-of-a-kind cameras from the 21st century Need the speed? Sigma 18-35mm F1.8 DC HSM in-depth review Ilford opens US lab to meet demand for black and white film development Goldfish all gone? Turn that empty tank into an underwater housing Canon's EF-S 17-55mm f/2.8 IS USM is a highly regarded fast normal zoom for APS-C SLRs, and in comparison to the Sigma, offers an extended zoom range and built-in image stabilization, which makes it a very flexible lens indeed. But when we compare the two purely in terms of image quality, it's clear that not only is the Sigma noticeably sharper than the Canon when both are set to F2.8, it's actually sharper at F1.8 than the Canon is at F2.8. In all other respects, it matches up well too. 3. Test results Editorial content Camera reviews Lens reviews Printer reviews Previews Sample images Articles Glossary Link directory Videos Product database Cameras Lenses Printers Software Smartphones Camera search Camera comparison Lens search Product timeline Browse all products Community Forums Challenges Galleries Polls My Profile My Settings My GearList Connect with dpreview Subscribe to the weekly newsletter About us Write for us Advertise with us FAQ Feedback Interest-Based Ads Privacy Legal All content, design, and layout are Copyright Digital Photography Review All Rights Reserved. Reproduction in whole or part in any form or medium without specific written permission is prohibited. Mobile site

10 QUICK LINKS: Videos Sample Images Camera Timeline Link Directory News Reviews Buying Guide Sample Images Articles Cameras Lenses Phones Printers Software Forums Galleries Challenges 4. Test results Search on dpreview.com Studio Tests (continued) Macro Focus Macro - 87 x 58 mm coverage Measured magnification: 0.26x Distortion: Negligible Minimum focus distance*: 26.5cm Working distance**: 10.0cm Focal length: 35mm * Minimum focus is defined as the distance from the camera's sensor to the subject ** Working distance is measured from the front of the lens to the subject We wouldn't necessarily expect a relatively short, fast zoom to be great for close-ups, but the Sigma acquits itself pretty well. Its minimum focus distance in manual focus mode is an impressively close 26.5cm, resulting in a somewhat higher maximum magnification than you'll get from a typical 24-70mm F2.8 zoom. Close-up image quality isn't bad either, at least when stopped down a bit. The image is soft wide open, but sharpens up pretty well in the centre at F2.8. The corners rather lag behind, but continue to improve on stopping down until our flat test chart shot looks sharp corner-to-corner at F11. There's minimal distortion, and only the slightest hint of blue/yellow chromatic aberration. Colour balance Third party lenses sometimes find themselves criticized for their colour balance and rendition compared to the camera manufacturers' own optics. We've looked into this by shooting an X-Rite Colorchecker Passport using the 18-35mm side-by-side with the Canon EF 24-70mm f/2.8l II USM. The images were shot under controlled fluorescent lighting, and a custom white balance set from the Passport's own grey card using the Canon lens. Images were shot in RAW on the EOS 700D, and converted in ACR using identical settings. Log in to dpreview Not a member? Register Pages Introduction Design and... Test results Test results Overall... Conclusion...

11 Sigma 18-35mm F1.8 DC HSM Canon EF 24-70mm f/2.8l II USM If you compare the colours in this rollover, we think you'll really struggle to see any significant differences between the two lenses at all. This doesn't come as much of a surprise to us, but it might to some sceptics. Flash shadowing One problem we might expect to see, given the lens's sheer physical length, is shadowing of the built-in flash at wideangle. This is indeed visible; on recent SLRs like the Canon EOS 700D, which lift the flash quite high above the lens, we saw some shadowing right at the bottom edge of the frame at focus distances. At the distances you'd most likely use the flash (~2 metres) it's pretty minor though, and effectively disappears if you zoom in a little bit, to just 20mm. Preview... With the EOS 700D, the 18-35mm gives visible flash shadowing at the bottom of the frame at 18mm and ~2m subject distance. But it's not too severe, and can be avoided by zooming in to just 20mm. Of course with the lens's super-fast aperture, you may not use flash very much at all for indoor shooting. Full Frame Coverage The Canon, Nikon and Sony mount versions of this lens will mount on full-frame DSLRs, and on Nikon cameras DX crop mode will be automatically selected (the camera will therefore shoot at reduced resolution). The rollover below shows the level of vignetting on full frame, with samples shot on a Canon EOS 6D through an Expodisc white balancing filter. The lens's image circle doesn't cover the 35mm full frame format fully at any focal length, giving severe vignetting at 18mm which decreases progressively on zooming in. There's still visible vignetting in the corners at 35mm, which doesn't entirely go away on stopping down, either. Latest reviews Sigma 18-35mm F1.8 DC HSM Sep 2, % Sony Alpha A3000 Aug 26, 2013 Canon EOS 70D Aug 15, 2013 Sigma USB Dock quick review Aug 12, Waterproof Group Test Aug 9, mm F1.8 24mm F1.8 35mm F1.8 18mm F8 24mm F8 35mm F8 Here's what the lens looks like shooting a real-world subject at 35mm on the EOS 6D. At F1.8 there's severe vignetting, pronounced pincushion distortion, and the corners are distinctly soft. At F8 things have cleaned up substantially, but there's still visible vignetting in the extreme corners, and of course the distortion remains. This is no surprise for an APS-C lens on full frame - it's simply not designed for the job. But you could use it at a pinch as a 35mm lens if necessary. Pentax Q7 Aug 8, % Sigma 17-70mm F2.8-4 DC MACRO OS HSM C Aug 5, % See more... Latest news This week Mobile madness? Our opinion on Sony's QX clipon cameras

12 Canon EOS 6D, 35mm F1.8 Background blur compared Canon EOS 6D, 35mm F8 One of the great attractions of fast lenses is the ability to isolate a subject by blurring the background. At first sight the 18-35mm may look like the ideal choice for such work - for any given angle of view it'll give noticeably more background blur at F1.8 than you'd get from an F2.8 zoom, and indeed match F2.8 on full frame. However, its relatively limited range means that a 17-50mm F2.8 can actually give better results if you compare both lenses shot wide open at their long end, purely in terms of the amount of background blur. This is illust rated in the rollover bellow. Sony reve als QX10 and QX100 camera modules for smartphones Dx O Optics Pro adds support for five recent cameras Olympus fraud saga rumbles on with UK prosecution Microsoft to acquire Noki a's smartphone business Dx OMark tests Canon EOS 70D sensor and lenses Back to the future: ten one-of-a-ki nd cameras from the 21st century Need the speed? Sigma 18-35mm F1.8 DC HSM in-depth review Ilford opens US lab to meet demand for black and white film deve lopment Goldfish all gone? Turn that empty tank into an underwater housing APS-C, 35mm F1.8 APS-C, 35mm F2.8 FF, F 55mm F2.8 APS-C, 50mm F2.8 Here you can see the extra blurring you can get from shooting at 35mm F1.8 compared to what you'd get from an F2.8 zoom at the same focal length. It's also clear that the F1.8 zoom off ers essentially the same background blur as shooting at an equivalent focal length and F2.8 on full frame. However, if you shoot at 50mm F2.8 on APS-C, moving the camera back to keep the subject size the same, then the background ends up looking just as blurred and less cluttered due to the narrower angle of view. What this means is that a lens of the 17-50mm F2.8 type is st ill a better choice for shooting head-and-shoulders port raits. Similar arguments apply for low light, high ISO shooting; the F1.8 zoom allows you to shoot handheld at lower ISOs for better image quality, and in principle should come close to matching a full frame camera with an F2.8 zoom in terms of overall image noise. But there are lots of complicating factors here, including the exist ence of image-st abilized F2.8 zooms that allow you to hand-hold at slow shutter speeds and use even lower ISOs, just as long as your subject isn't moving. (Sony and Pentax users, of course, benefit from image st abilization with all lenses.) Video Autofo cus The Sigma 18-35mm F1.8 HSM uses a ring-type ultrasonic motor, which provides reasonably smooth autofocusing should you wish to change your focus point during movie recording. The focus motor is relatively quiet but it's not silent, so the camera's built-in microphone may well pick it up. Both the AF perf ormance, and how audible the lens's operation ends up on your soundtrack, will be dependent upon the camera used. The examples below show movie mode AF on the Canon EOS 100D, which allows refocusing on a new subject by touching the rear screen during recording. Its Hybrid AF sy st em is also one of the better implementations of movie focusing on an SLR. Ov erall the Sigma does OK here, at least for an SLR lens that's primarily designed for st ills photography. Focusing is pretty positive, but the motor can be heard in a quiet environment. Sample 1 - Quiet indoor environment Here we st art with focus on the left side figure, then switch the right side and back again. In a quiet room indoors, the clicking of the focus motor is clearly audible on the soundtrack.

13 Sigma 18-35mm f/1.8 DC HSM video autofocus - quiet indoor environment Sample 2 - Outdoor environment with nearby traffic Here we st art with focus on the foreground, then switch the background and back again. This is recorded in a park with nearby traffic, which in this case drowns out the motor noise. Sigma 18-35mm f/1.8 DC HSM video autofocus - outdoor environment with nearby traffic 4. Test results Editorial content Camera reviews Le ns reviews Printer reviews Previews Sample images Articles Glossary Link directory Videos Product database Cameras Le nses Printers Software Smartphones Camera search Camera comparison Le ns search Product timeline Browse all products Community Forums Challenges Galleries Polls My Profile My Settings My GearList Connect with dpreview Subscribe to the weekly newsletter About us Write for us Adve rtise with us FAQ Feedback Interest-Based Ads Priva cy All content, design, and layo ut are Co pyright Digital Photography Review All Rights Reserv ed. Reproduction in whole or part in any form or medium without specific written permission is prohibited. Mobile site Le gal

14 QUICK LINKS: Videos Sample Images Camera Timeline Link Directory News Reviews Buying Guide Sample Images Articles Cameras Lenses Phones Printers Software Forums Galleries Challenges 5. Overall Image quality Search on dpreview.com Overall image quality The 18-35mm delivers such extraordinary results in studio testing that it barely seems believable. However in real-world shooting it is genuinely capable of delivering wonderfully detailed images when shot wide open, at least when it's properly focused. This is shown in the examples below, which were shot at each end of the zoom, then converted from RAW with sharpening turned off in ACR and a relatively modest small-radius unsharp applied in Photoshop to bring out fine detail (amount = 150, radius = 0.3). Canon EOS 100D, RAW + ACR Log in to dpreview Not a member? Register 18mm F1.8 35mm F % crop, lower centre 100% crop, centre Pages Introduction Design and... Test results 100% crop, lower right 100% crop, bottom right corner At 18mm sharpness remains impressively high out to the edge of the frame, although green/magenta chromatic aberration becomes quite visible. Sharpness visibly drops right in the extreme corners, but most of the time you'll lose much more sharpness to the limited depth of field at F1.8 than you will to lens aberrations. 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 Test results Overall... Conclusion...

15 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 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. Preview... The example below is typical of the kind of focus problem we saw. These two images were shot just a second apart, but while the top one is in more-or-less perfect focus, the other is slightly off - the camera has actually focused somewhat in front of the statue. This type of misfocusing seems most prevalent with relatively low-contrast subjects, and is often enough to take the edge off the sharpness. This means it can be difficult to make the most of the lens's excellent optics. Canon EOS 700D, 35mm F2, 1/4000 sec ISO 200 Latest reviews Sigma 18-35mm F1.8 DC HSM Sep 2, % Sony Alpha A3000 Aug 26, 2013 Canon EOS 70D Aug 15, 2013 Sigma USB Dock quick review Aug 12, 2013 When pinning down what's going on here, we have to draw a distinction between focus accuracy and consistency. Point an SLR at the same subject and autofocus 10 times while looking through the optical viewfinder, and it'll probably give 10 slightly different results. How close it comes on average to focusing correctly defines the accuracy, whereas the spread of focus distances describes the consistency. We're not going to delve in detail into why this happens, however it boils down to the fact that SLRs don't use the main image sensor itself for focusing (except when in live view), but instead a different sensor with its own light path. This arrangement can give rise to both random misfocusing, and more systematic focus errors. The latter can to some extent be fixed using the 'Autofocus Microadjustment' settings in many modern SLRs, and offered in a more advanced form by Sigma with its USB Dock and Optimization Pro software. A consequence of all of this is that in principle you'll get the very best results at large apertures by focusing and shooting in live view. This has its own pitfalls though - for example when focusing manually with Nikon's DX SLRs you have to remember to set the aperture to F1.8 before entering live view, as they're incapable of adjusting the lens's diaphragm during viewing. If you initiate live view at a smaller aperture, then you risk getting misfocused images. Meanwhile Canon users may have to set the aperture to F1.8 and press the depth of field preview button to force the lens wide open for accurate manual focusing, when shooting in bright light. Autofocus microadjustment We looked at whether the focus problems we saw from the 18-35mm could be mitigated by using autofocus microadjustments. With a Sigma USB Dock to hand, we set about determining and programming in a full set of autofocus microadjust parameters for all of Sigma's specified focal lengths and focus distances (18, 24, 28 and 35mm; infinity, 0.5m, 0.35m and 0.28m). This took several hours to set up, even with specialised focusing targets to hand. The screenshot from Sigma Optimization Pro below shows the adjustments we ended up with (note that every copy of the lens is expected to require different numbers). Latest news This week 2013 Waterproof Group Test Aug 9, 2013 Pentax Q7 Aug 8, % Sigma 17-70mm F2.8-4 DC MACRO OS HSM C Aug 5, % See more... Mobile madness? Our opinion on Sony's QX clipon cameras

16 Sony reveals QX10 and QX100 camera modules for smartphones DxO Optics Pro adds support for five recent cameras Olympus fraud saga rumbles on with UK prosecution Microsoft to acquire Nokia's smartphone business DxOMark tests Canon EOS 70D sensor and lenses Back to the future: ten one-of-a-kind cameras from the 21st century Need the speed? Sigma 18-35mm F1.8 DC HSM in-depth review Ilford opens US lab to meet demand for black and white film development Goldfish all gone? Turn that empty tank into an underwater housing 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. 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? One point implicit in all of these discussions is that we're examining images for pixel-level sharpness, which is a hugely demanding criterion. Images don't necessarily have to be this perfectly focused to be entirely acceptable when viewed on-screen or made into in anything other than very large prints. So while accurate autofocusing is highly desirable, slight misfocus doesn't necessarily spoil a photograph completely. This is where each individual photographer has to make their own decision about what they're prepared to accept, based on personal experience and preference. However, we believe most potential buyers for this lens will be demanding users - either serious enthusiasts or professional photographers. And while we think that they'll be delighted with the image quality the lens delivers when properly focused, they won't generally find this kind of hit-and-miss focusing at F1.8 very acceptable; the lens just doesn't reliably deliver usable images every time. This doesn't mean that there's no point in buying the lens at all - its outright image quality at normal working apertures is reason enough to get one - but it does mean that we'd recommend testing before you buy, if at all possible. Of course we've only used the Canon mount version of the lens - it's possible other versions may work better. Specific image quality issues As always, our studio tests are backed up by taking hundreds of photographs with the lens across a range of subjects, and examining them in detail. This allows us to confirm our studio observations, and identify any other issues which don't show up in the tests. In real-world shooting the Sigma 18-35mm produces consistently excellent results - just as long as the camera can focus it accurately enough. Chromatic aberration The 18-35mm doesn't show too much in the way of chromatic aberration, but it's visible if you go looking for it. Under different conditions it can show the two main types of CA, lateral and longitudinal. Lateral chromatic aberration is visible as colour fringing towards the edges and corners of the frame, and as usual is strongest at wideangle. It tends to be most obvious when the lens is stopped down a bit, which brings the fringing into sharpest focus. It's relatively easy to correct in post-processing, but will be visible in most cameras' JPEG output (although many Nikon SLRs will automatically remove it). The Great Court of the British Museum is something of a torture test for this type of CA, and in the uncorrected example below you can clearly see green/magenta fringing across much of the roof structure when viewing the image up-close. This is simple enough to correct in most RAW converters - here we're using Adobe Camera RAW's 'Remove Chromatic Aberration' control. RAW + ACR, no correction RAW + ACR, CA corrected

17 Canon EOS 100D, 18mm F5.6, 1/100sec ISO % crops, upper left Longitudinal chromatic aberration can also be visible occasionally, as colour fringing around out-of-focus areas of the frame when shooting at large apertures. This tends to be strongest at the long end of the zoom, but is never very objectionable. The example below illustrates just about the worst case scenario, with red fringing in front of the plane of focus, and green fringing behind, accentuated by the grass being overexposed. This type of CA is generally less straightforward to remove in post-processing, as it shows up differently in every image. 100% crop in front of focus plane Canon EOS 100D, 35mm F % crop behind focus plane 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 18-35mm does reasonably well with respect to flare, given its fast aperture and the sheer amount of glass used in its construction. In real-world use shooting in bright mid-summer sun we've not seen any obvious problems, but the usual caveats apply - it's essential to keep the front element clean, and always

18 best to shoot with the hood in place too. The examples below give an idea of how the lens deals with the sun in or around the frame. In the first set we're shooting at wideangle with the sun in the corner of the frame, and comparing what we see with lens shot wide open and then stopped right down to make flare patterns most defined. Here the results depend upon the aperture; image contrast is maintained well at F1.8, and holds up on stopping down to about F4. Diagonal flare patterns become visible at F5.6, and shadow detail starts to deteriorate too. Both effects becomes more pronounced at smaller apertures, and at F16 we see well-defined and intenselycoloured flare patterns, along with substantial loss of shadow detail. 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. 18mm, F1.8, sun in corner of frame 18mm, F5.6, sun in corner of frame 18mm, F16, sun in corner of frame 35mm, F5.6, sun just outside frame Background blur ('bokeh') One genuinely desirable, but difficult to measure aspect of a lens's performance is the ability to deliver smoothly blurred out-of-focus regions when trying to isolate a subject from the background, generally when using a long focal length and large aperture. The 18-35mm gives you a decent degree of control over depth of field due to its large maximum aperture. As always you'll get the most-blurred backgrounds shooting at the long end of the zoom, and here the 18-35mm's rendition of out-of-focus areas tends to be pretty attractive. The examples below give some idea of what to expect. In the first the subject distance is somewhere around 3m, which means that the degree of background blur isn't huge. But it's sufficient to focus attention on the fountain, and the blurring is generally attractive. You'll get much more background blur when shooting at close focus distances, as always, and this is shown in the second example. Again the effect is smooth, although here the just-out-of-focus regions in the lower half of the frame show slightly harsh edges. Distant Bokeh Close-up Bokeh 35mm F1.8, Canon EOS 100D 35mm F1.8, Canon EOS 100D

19 Background detail, upper centre Detail crop, upper centre Overall though, the lens's wideangle-to-normal focal length range means that it can't match a cheap 50mm F1.8 prime if getting strongly-blurred backgrounds is a top priority. 5. Overall Image quality Editorial content Camera reviews Lens reviews Printer reviews Previews Sample images Articles Glossary Link directory Videos Product database Cameras Lenses Printers Software Smartphones Camera search Camera comparison Lens search Product timeline Browse all products Community Forums Challenges Galleries Polls My Profile My Settings My GearList Connect with dpreview Subscribe to the weekly newsletter About us Write for us Advertise with us FAQ Feedback Interest-Based Ads Privacy Legal All content, design, and layout are Copyright Digital Photography Review All Rights Reserved. Reproduction in whole or part in any form or medium without specific written permission is prohibited. Mobile site

20 QUICK LINKS: Videos Sample Images Camera Timeline Link Directory News Reviews Buying Guide Sample Images Articles Cameras Lenses Phones Printers Software Forums Galleries Challenges 6. Conclusion and Samples Search on dpreview.com Conclusion - Pros Super fast constant F1.8 maximum aperture Excellent optics, even wide open Fast, silent autofocus Solid build quality without being over-heavy Compatible with Sigma's USB dock and Optimization Pro software Conclusion - Cons Restricted zoom range Needs detailed AF microadjustment for best results Inconsistent autofocus in difficult conditions even after microadjustment Physically rather large for a standard zoom Overall conclusion The Sigma 18-35mm F1.8 DC HSM was announced to widespread excitement, if only for the company's sheer ambition in making such a fast zoom. But this inevitably came with a degree of scepticism - it's hard enough to make an F2.8 zoom that's really sharp wide open, so could an F1.8 zoom possibly work? Then again, Sigma's recent track record with lenses like the wonderful 35mm F1.4 DG HSM gave hope that the company might possibly be able to deliver. What nobody quite anticipated, ourselves included, was that Sigma could conceivably deliver a lens with optics this good. The 18-35mm isn't just sharp for a fast zoom; in terms of outright image quality, it's a match for many fast primes, even when shot wide open. Obviously, the restricted zoom range will have helped, but even so this is a considerable achievement on Sigma's part. The lens can more-or-less replace a set of primes across its range with minimal compromise in image quality. This does all come with one serious caveat though, and that's to do with focusing. We've used two copies of the Canon mount version of the lens, and found autofocus to be rather hit-and-miss with both under lessthan-ideal conditions (for example with low contrast subjects). Part of the problem here is that the kind of relatively small focus errors sufficient to take the edge off the image sharpness at F1.8 are essentially invisible in the optical viewfinders of SLRs, so it's difficult to spot focus errors while you're shooting. Setting up full AF microadjustment using Sigma's USB dock and Optimization Pro software certainly helps with overall focus accuracy, but doesn't eliminate shot-to-shot inconsistency. What this means is that while the 18-35mm has truly superb glass, autofocus problems mean that it can be difficult to get the full benefit when shooting at large apertures, which somewhat negates the lens's key selling point. Not every wide-open shot will be misfocused by any means, and you'll still get prime-like image quality when shooting stopped-down. But unfortunately, the fact that you can't rely on always getting correct focus makes the lens a bit less easy to recommend over an F2.8 zoom in the 17-50mm class. This is unfortunate, because in almost every other respect the Sigma is an excellent lens. It handles well, with smooth zoom and focus rings and all of Sigma's latest thoughtful design touches. In terms of the less easily quantifiable aspects of image quality, it offers attractively-blurred backgrounds, and isn't overly susceptible to flare given its speed. And, of course, it's not just the fastest zoom on the market, but faster than almost any prime wider than 24mm that you can mount on an SLR (with the sole exception of Sigma's own venerable 20mm F1.8). The Final Word Log in to dpreview Pages Not a member? Register Sigma has been on something of a roll recently, with lenses like the 35mm F1.4 offering excellent optics at a very competitive price, and it's clear from both technical tests and real world shooting that the 18-35mm F1.8 is following on in much the same vein. Its relatively narrow zoom range is undeniably a little restrictive, but on the other hand, the image quality it can offer over that range is absolutely stellar. It's let down a little by inconsistent autofocus, which makes it difficult to get consistently sharp results every time when shooting wide open. But if you're prepared to live with this, the 18-35mm is capable of delivering truly exceptional results. Introduction Design and... Test results Sigma 18-35mm F1.8 DC HSM Category: Normal Lens Poor Compare mode OFF Excellent Optical Quality Build Quality Autofocus Test results Overall... Conclusion...

21 Ergonomics and Handling Value Overall score 86% Good for Not so good for Enthusiast APS-C users looking for the very best image quality available from a normal zoom, and willing to spend a bit of time setting up autofocus micro-adjustments or using live view focusing for the sharpest results. Photographers who like to travel light, or need a wide-ranging zoom. The Sigma 18-35mm F1.8 DC HSM is an extraordinary lens, offering prime-level image quality in the fastest zoom ever made for SLRs. Its 28-50mm equivalent range is a little limiting though, and inconsistent autofocus means that it can be difficult to make the most of the excellent optics when shooting at large apertures. Preview... Latest reviews Recommended links Want to make sure you don't miss out on any future reviews? Sign up for our free weekly newsletter! Enter the 'Third Party Lens Talk' Discussion Forum Sigma 18-35mm F1.8 DC HSM A on DxOMark Sigma 35mm F1.4 DG HSM lens review Tamron 24-70mm F2.8 Di VC USD lens review Sigma 18-35mm F1.8 DC HSM Sep 2, % Sony Alpha A3000 Aug 26, 2013 Samples Gallery There are 45 images in the review samples gallery and 34 images in the preview samples gallery. Please do not reproduce any of these images on a website or any newsletter / magazine without prior permission (see our copyright page). We make the originals available for private users to download to their own machines for personal examination or printing (in conjunction with this review), we do so in good faith, please don't abuse it. Unless otherwise noted images taken with no particular settings at full resolution and processed with default settings (no lens corrections) in Adobe Camera Raw. Canon EOS 70D Aug 15, 2013 Sigma USB Dock quick review Aug 12, Waterproof Group Test Aug 9, 2013 Pentax Q7 Aug 8, % Sigma 17-70mm F2.8-4 DC MACRO OS HSM C Aug 5, % See more... Latest news Sigma 18-35mm F1.8 DC HSM A review samples - 2nd September 2013 This week Mobile madness? Our opinion on Sony's QX clipon cameras

22 Preview Samples Gallery Sony reveals QX10 and QX100 camera modules for smartphones DxO Optics Pro adds support for five recent cameras Olympus fraud saga rumbles on with UK prosecution Microsoft to acquire Nokia's smartphone business DxOMark tests Canon EOS 70D sensor and lenses Back to the future: ten one-of-a-kind cameras from the 21st century Need the speed? Sigma 18-35mm F1.8 DC HSM in-depth review Ilford opens US lab to meet demand for black and white film development Goldfish all gone? Turn that empty tank into an underwater housing Sigma 18-35mm F1.8 DC HSM A preview samples - updated 10th June Conclusion and Samples Editorial content Camera reviews Lens reviews Printer reviews Previews Sample images Articles Glossary Link directory Videos Product database Cameras Lenses Printers Software Smartphones Camera search Camera comparison Lens search Product timeline Browse all products Community Forums Challenges Galleries Polls My Profile My Settings My GearList Connect with dpreview Subscribe to the weekly newsletter About us Write for us Advertise with us FAQ Feedback Interest-Based Ads Privacy Legal All content, design, and layout are Copyright Digital Photography Review All Rights Reserved. Reproduction in whole or part in any form or medium without specific written permission is prohibited. Mobile site