When this lens was announced, I did the biggest double-take I think I’ve ever done in my career as a photographer.  An f/1.8 zoom lens?  Tis madness, I tell you!  But no, this is the real deal.  The first f/1.8 zoom for common DSLRs is here.  Crop sensor DSLRs, that is.

That’s the second thing that went through my mind.  It’s for a crop sensor.  While certain elitists are quick to dismiss crop-sensor lenses, I’m a lot more open-minded.  To most photographers, a crop-sensor just means two things:  portability and affordability.

Of course if a lens is the very first to accomplish something, that isn’t necessarily a good thing.  Often times in an un-crowded market with no competition, the pioneers are only of “passable” quality.  So, how does this milestone lens perform?  Watch the video, and read on!

A big thank-you to the folks at Sigma for sending us this lens, it was a thrill to shoot with!  You can purchase the Sigma 18-35 for $799 here: B&H PhotoAdoramaAmazon

Verdict

Okay, let’s just get the obvious stuff out of the way:

  • Construction
    Superb.  In fact in appearance and feel, this Sigma “Art” series lens is more like a Zeiss prime than Canon L glass.  For those of you Canon die-hard fans, yes that is meant to be a compliment to the Sigma, though not an insult to Canon’s great pro-grade lenses.  ;-)  Either way, the 18-35 is a “little hunk”.  It’s solid and hefty, yet not massive / overweight.
    I don’t know how the Sigma would directly compare against Canon / Nikon lenses with respect to weather sealing, but it’s safe to assume that this rugged and ready for almost anything.
  • Sharpness
    We tested this lens on the highest resolution Canon crop-sensor camera body currently in production, the brand new Canon 70D. The 18-35 effortlessly resolved amazing sharpness at all focal lengths and at all apertures, with an enormous “sweet spot” of perfect sharpness that extends easily to both the vertical edges and horizontal edges, with only the extreme corners being mildly soft.
    Sigma-18-35-lens-review-7 Sigma-18-35-lens-review-7-cropHaving said that, I must admit that as sharp as this lens is wide open, the extreme corners stay “slightly soft” until f/5.6 or f/8.  Corner sharpness is still pretty awesome compared to any other lens, including both fast primes and f/2.8 zooms, but this lens is clearly optimized to be a fast, sharp lens in the central area.
  • Bokeh / Background Blur
    The Sigma 18-35 is certainly taking crop-sensor cameras in a very beautiful, desirable direction with respect to DOF.
    Sigma-18-35-lens-review-8 Sigma-18-35-lens-review-9
    It has never been easy to achieve that beautiful look of shallow DOF on a crop-sensor DSLR, at wider angles.  Even if you bought the extremely expensive 24mm f/1.4 primes available for full-frame, you were still stuck at around the equivalent of 35mm which is hardly “wide angle”.  It would have been ground-breaking enough for Sigma to deliver 18mm f/1.8 to crop-sensor users, but do it in the form of a zoom lens is incredible.
    Needless to say, the DOF is gorgeous.  The bokeh is quite pretty, too, and in my opinion it delivers more pretty background blur than most photographers will ever need.  Would you get better DOF and bokeh by using a 35mm or 24mm f/1.4 prime on full-frame?  Certainly.  However we would be comparing a zoom against a prime at that point.  For most photographers the difference probably wont be worth the added thousand or two dollars that separate the two systems, and the ability to zoom is icing on the cake.
    Bottom line-  This lens delivers similar DOF on a crop sensor to a 24-70 f/2.8 zoom on full-frame!
  • Vignetting
    Vignetting is well-controlled, but present.  If you have a camera with great shadow recovery capabilities, at most ISOs you will see zero loss of image quality when you correct the vignetting.
    I will say one thing, however-  I’d rather have an f/1.8 lens with very low vignetting, than an f/1.4 with very extensive vignetting.  I have seen some lenses that are so bad, they really only render the dead-center of the image to be brighter between the first 1-2 stops of aperture.  So all in all, I’m very happy that Sigma designed the lens the way they did.
  • Distortion
    Like vignetting I do not want to spend much time gauging this aspect of image quality until Adobe gets a chance to build a profile for  this lens, because in my opinion it usually becomes a non-issue when a lens profile correction is used.  Having said that, the 18-35 exhibits the traditional type of distortion for such an exotic zoom:  A tiny, minor amount of barrel distortion at the wide end, and a tiny, minor amount of pincushion distortion at the long end.
  • Macro Capability
    I originally claimed that this lens could replace 3 pro-grade prime lenses, however if you count a macro lens you could say this lens is almost equal to four lenses!
    The Sigma 18-35 cannot reach full 1:1, but 1:4.3 is nothing to scoff at!  The lens is quite sharp even wide open at 35mm and the closest focusing distance, and is incredibly sharp by f/2.8.  (Where most macro lenses start anyways!)

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  • Chromatic Aberrations
    Considering that this lens marks the very first venture into the prime-zoom arena, CA is surprisingly low.  It’s there, but even without a lens profile Adobe’s various Camera Raw tools are already completely eliminating it.  Once again, a non-issue for me personally.
  • Flare & Sunstars
    Flare is well-controlled, and sunstars are nice.  No surprises here.
  • Coma
    I didn’t forget you, astro-photographers!  As a fast-aperture wide-angle lens, one question you’re probably asking is “is the coma okay for star photos?”  I’m happy to say that yes, coma is kept to a pleasant minimum on the Sigma 18-35.
    In fact I really don’t see much of the “bird wing” type coma at all in my meteor timelapse photo; if anything there is just a minor radial stretch of pixels, which is probably just an aspect of sharpness.

Sigma-18-35-lens-review-1(Click HERE to view a larger version!)

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Who Should Buy It

Now we get to my favorite part of any review-  what type of photography do you shoot, and should you consider this lens for it?  At “only” 18-35mm, (roughly equivalent to 27-50mm on full-frame) this is definitely a specialized lens.  So what is this lens best at?

  • Anything Night-Time
    First and foremost, this lens is nocturnal.  If you shoot star trails, twilight landscapes, or anything where every bit of light counts, then this lens is for you.  With great corner sharpness and very un-obtrusive coma, this lens makes an excellent “nightlapse” or “nightscape” camera.  I only wish it were wider!

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  • General Close-Range Photojournalists
    As much as this lens is fantastic for night-time landscapes, cityscapes, etc, in my opinion the focal range is less optimized for landscapes (18mm is not really considered ultra-wide on a crop-sensor) …and much more optimized for general low-light photojournalism.  The 18-35mm focal range includes the equivalent of three very popular full-frame primes: 28mm, 35mm, and 50mm.  If you can imagine how awesome it would be to have all three of these primes in one single lens, then you can imagine what the Sigma feels like.
    From general hobbyists taking pics at birthday parties, to full-time wedding and portrait professionals even-  if you are interested in achieving amazing sharpness, DOF and low-light capabilities that were previously only available to full-frame systems, this is a good choice.
    Make no mistake though, photojournalists-  this lens is not really meant to compete with zooms, f/2.8 or otherwise.  It is meant to replace 2-3 prime lenses.  If you absolutely cannot live without a 3X+ zoom range, then consider something else like a 17-55 f/2.8.  However personally I would much rather have this lens for general close-range photojournalism.

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  • Group Photos
    This certainly isn’t a genre of photography all by itself, however I really want to point out one thing that this lens does beautifully, something that has plagued other fast zooms for ages:  field curvature. The Sigma 18-35 has almost none whatsoever!  (Check the 100% edge crop above, and in the video)
    Before, especially on exotic f/2.8 zooms, you had serious issues with taking group photos and having people on the edge be not just soft, but literally out of focus due to severe field curvature.  With the Sigma, you could even shoot at f/1.8 at 18mm and not worry about faces getting soft near the edges.
    Of course you would want to stop down when shooting multiple rows of people, but that goes without saying.  However I would say you even have an advantage on a crop-sensor for group photos with this lens, because stopping down gives you MORE depth than the same aperture on a full-frame camera.  Wedding and portrait photographers always talk about how they love to achieve super-shallow depth, but they forget that many times a photographer’s goal is the exact opposite!
  • Medium-Close Range Action Sports Photographers
    Just like photojournalists, action photographers care about light although for slightly different reasons.  In other words, even if you’re not obsessed with shallow DOF, you can really benefit from the faster shutter speeds that an f/1.8 zoom affords you.  That’s ~1.3 stops faster than an f/2.8 zoom, two whole stops faster than your f/3.5 kit zooms, or more once you stop that kit lens down while zooming in.  In low-light sports this could make the difference between totally blurry and totally sharp.
  • Any and all Videographers
    If you shoot video, you need to consider this lens.  With a 16:9 crop this lens will render utterly perfect sharpness, center-to-corner, at all apertures and focal lengths.  The focus and zoom rings are smooth and well-dampened, with a decent amount of “throw”.

Compared to Primes and Zooms

As we already hinted a little bit, it’s hard to compare this lens to others because it goes in a completely new direction.  While you might be tempted to compare the 18-35mm to “regular” 17-55mm f/2.8 mid-range zooms on a crop-sensor, in my opinion the Sigma compares better with primes.  And as such, there simply is no single lens on the market that can compare; really you should be comparing the Sigma 18-35 against 2-3 primes. This introduces a whole can of worms-  Firstly, there simply is no 18mm f/1.8 crop-sensor prime available. There’s the Sigma 20mm f/1.8, but it is pretty old and quite soft wide open. Next, the Canon / Nikon 24mm f/1.4‘s are very pricey full-frame lenses, so they are once again not very practical for a crop sensor shooter.  Thus, we are left with 28mm f/1.8 primes (both Canon and Nikon make them) …and of course the 35mm f/1.8 and f/1.4 primes that are made specifically for crop-sensors.  (Nikon and Sigma make some)

In this light, the Sigma 18-35 f/1.8 makes a whole lot of sense.  I work as a wedding photojournalist, and as far as mid-range lenses are concerned I would definitely rather have this Sigma 18-35 f/1.8 plus a more versatile zoom like the Nikon 16-85, instead of a single f/1.4 prime and a 17-55mm f/2.8 zoom.

If you’re having trouble wrapping your head around this whole comparison, just remember:  Barely ~10-15 years ago people were having this very same discussion about f/2.8 zooms versus f/2.8 primes-  f/2.8 zooms were finally becoming sharp enough that f/2.8 primes were becoming obsolete.  Just some food for thought.

Compared to Full-Frame Options

Sure, there are pretty slim pickings for crop-sensor primes, and if you’re planning on sticking with crop-sensor cameras then the Sigma will be reigning champion for many years to come.

However, what about simply comparing the Sigma 18-35 f/1.8 against, say, a full-frame camera and 2-3 primes, or an f/2.8 zoom?  The DOF (depth of field, aka background blur) on an f/2.8 zoom on full-frame is about the same as the DOF of an f/1.8 zoom on a crop-sensor.  And of course if you throw an f/1.8 or f/1.4 prime on full-frame, you’re certainly going to achieve more shallow DOF and better low-light performance overall.

At this point, the comparison becomes even more difficult.  In my opinion however it is not fair to simply compare a single full-frame camera with one lens, and a single crop-sensor camera with one lens.  You need to compare the systems as a whole.

Indeed, the Sigma 18-35mm f/1.8 at $799 is not cheap, and you can probably buy 2-3 equivalent full-frame primes for the same price-  Nikon’s 28mm f/1.8 G and 50mm f/1.8 G would set you back about $800, for example, if you took advantage of one of Nikon’s common rebates.

However what most “FF fanboys” fail to do is, compare the entire system and overall long-term costs.  And that way, any way you slice it, full-frame becomes more expensive than crop-sensors by $1,000-$3,000 or more.

The bottom line, to me, is that sensor technology has improved quite a lot over the past few years, and nowadays a crop sensor is really all I need for a lot of the casual / outdoor photography that I do.  And with every year that passes, I become less interested in what setup is the absolute champion on paper, and more excited about which setup is smaller, lighter, affordable, and yet still sharp and detailed enough to make big prints.

The Ultimate Kit

If I were a wedding / portrait photographer, the two lenses I would just love to have for a crop-sensor camera are currently the Sigma 18-35mm f/1.8 and the Sigma 50-150 f/2.8 OS.  You just can’t go wrong with these two lenses.

If I were more into landscapes and other ultra-wide photography, maybe I would consider adding an ultra-wide zoom to my kit, such as the Tokina 11-16 f/2.8.

If I were really into portraiture I might add an 85mm to that kit instead, either the Nikon 85mm f/1.8 G or the Sigma 85mm f/1.4 EX.

What Next From Sigma?

I feel that I cannot properly conclude this review without also mentioning the one thing that many photographers talked about when the lens was firs announced- “I wish it were full-frame!”

Sure, a full-frame 18-35mm lens would be incredible.  It would certainly be much better suited for astro photography, night timelapses, etc.

To some purists, this lens’ crop factor may be seen as a disappointment.  To me however it is simply a proof-of-concept, and a foreshadowing of things to come.

Don’t forget that Sigma has always had their full-frame f/1.8 trio, the 20mm, 24mm, and 28mm.  So they clearly have experience designing lenses in this range.  I think that while the rumors of a full-frame 24-70 f/2 are just wishful thinking, we may indeed see more f/1.8 or f/2 zooms from Sigma in the next ~6-12 months.

Also receiving very high acclaim is the new Sigma 35mm f/1.4 EX, a full frame prime in their new “Art” series of lenses.  If you ask me, based on the natural progression of f/1.4 primes from Sigma, (50mm, 85mm, 35mm) …it is obvious that they are creating a series of f/1.4 primes in order of popularity.  What then comes next in such a lineup?  A 24mm f/1.4.  Again rumors are rumors and I never listen to them very much, but logic dictates that a 24mm f/1.4 or similar full-frame prime comes next from Sigma.  For this, I am very excited.  Would I still buy the 18-35 f/1.8 EX?  You bet!

Sigma-18-35-lens-review-14(Vertical Panorama – Self Portrait)

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All in all, we absolutely recommend this lens.  It is totally worth the price, and it is one of the rare lenses that could actually elevate your photography to a new level when used to its full potential.

Thanks for reading, folks!

Take care, and happy clicking,
=Matthew Saville=