I remember not that long ago there were two types of lenses. Brand lenses, those designed by known manufacturers for their own cameras, such as Canon, Nikon, Pentax and Olympus, and the cheapskate third party lenses you’d buy if you couldn’t afford the first type. Brand lenses were more expensive, but well worth the extra price. Better build quality, better optical capability, better dependability, better compatibility, better autofocus and fewer quality control and manufacturing issues were what you got for your hard-earned cash. Not to mention respectful nods from anyone spotting letters Nikkor or a red ring around the front of that lens barrel. A few years have gone by now and situation seems to be changing, however. Third party manufacturers have moved the game up and started producing some serious alternatives. Sigma is very keen to prove the point with the launch of its latest lens, the new 18-35mm f/1.8 DC HSM for APS-C DSLR cameras. In this article, I will introduce you to this new lens and give insight as to why it is such an important step forward in current smaller-format lens market.
What is it About This Lens?
In a nutshell, this new lens sports a useful wide-to-normal focal length range of 18-35mm on an APS-C sensor camera (27-52.5mm full-frame equivalent), for which it is designed. It also has Sigma’s fast HSM AF motor, which is similar to Nikon’s SWM and Canon’s USM technology. Zooming and focusing are internal, so length remains constant. The new Sigma also has 17 elements in 12 groups and sports 9 rounded diaphragm blades for smooth out of focus highlights. Some of the optical elements are aspherical while minimum focus distance is 0.28m. The lens accepts 72mm filters and is, unfortunately, not protected against dust and moisture. It’s also quite hefty at around 810g. The lens sits in Sigma’s Art lineup alongside Sigma 35mm f/1.4 HSM and is designed with aesthetic flexibility in mind. But the spotlight is the f/1.8 aperture throughout the zoom range. Oh yes. This is the first ever f/1.8 zoom lens for DSLRs.
It’s a bit too early to say anything about the optical properties of the Sigma 18-35mm f/1.8 – we haven’t had a chance to play with it, pre-production version or otherwise. But optical quality is not even the point of it. I know it sounds silly at first, but bear with me, because this lens marks an important milestone for APS-C camera lens design. Finally, you can truly say that this zoom lens lets you leave several primes at home without any serious compromise (assuming optical quality is good enough). It’s as fast as those 35mm f/1.8-2 class prime lenses for APS-C cameras and offers the advantage of variable focal length. But there’s also the bigger picture.
The Problem of Lens Speed
I am a big fan of larger format sensors and film, and love my D700 and Mamiya RZ67 for what they are. Even so, I can also appreciate the advantages smaller sensor cameras carry, such as reduced size, weight and price. Now, price is something that’s easy to understand, and weight and size advantages are just as important. However, in my opinion, no APS-C or smaller sensor camera system is complete without a set of fast lenses. So, these camera systems should either exploit size advantage and give the option of smaller lenses, or give plenty of wide aperture lenses. Better still, they should include both. Most manufacturers got caught up in focal-length “equivalence”, and that’s an important aspect. For example, a 50mm lens, while very nice on a full-frame camera, is nowhere near as flexible on APS-C camera. You need a 35mm lens for that. But what about aperture? That’s where brand manufacturers haven’t really been working hard, to say the least. It’s nearly impossible to replicate the shallow depth of field that a large sensor helps to provide with fast lenses at given framing using APS-C camera. For example, if you put a 35mm lens on APS-C camera, set the aperture to f/2 and focus at about 5ft away, you would have around 0.5ft of depth of field. If you put a 50mm lens on a full-frame camera (for similar framing purposes) and focus from the same distance, you could set your aperture to f/2.8 and get the same 0.5ft depth of field. Replicating depth of field of a f/1.4 lens mounted on full-frame camera would require you to have f/1 lens for your APS-C camera. Lenses that “fast” are incredibly difficult to design (especially with AF) and, of course, are a bit too much to expect. However, f/1.4 lenses are much simpler and, if designed for APS-C cameras, would be quite small. For this reason I believe there should be many more wide-aperture lenses for APS-C, which would make the crop sensor systems that much more attractive.
There’s only one f/1.4 AF lens specifically designed for APS-C DSLRs that I know of. Want to guess who designed it? Yep, Sigma – it is the 30mm f/1.4 DC HSM. And now Sigma is in the spotlight with its 18-35mm f/1.8 constant aperture zoom.
Even with the latest super-fast 18-35mm f/1.8 zoom lens, Sigma isn’t the only manufacturer to try and exploit smaller sensor advantages to the fullest. While Sony, Panasonic and other compact system camera and DSLR manufacturers release and re-release slow and often crappy zoom lenses with very narrow apertures, Fujifilm is busy with its speedy optics. The 18-55mm f/2.8-4 Fujinon is almost a stop faster than equivalent lenses in other mounts throughout the zoom range (albeit at a hefty price, perhaps, but that’s a different topic). The 35mm f/1.4 has been extremely well received, too. A 23mm f/1.4 and 56mm f/1.2 lenses are in the pipeline. That’s why I seriously consider Fujifilm X-mount mirrorless cameras as a future addition to my Nikon gear that I’d use for my personal work, travel, street photography and, oh yes, weddings.
Faster lenses are not just about better low-light performance. After all, modern cameras are getting better and better at ridiculously high ISO settings. It’s also about shallow depth-of-field and aesthetics. Fujifilm gets it, Sigma gets it. The big boys, for some reason, still don’t.
The Problem of Price and Innovation
A few years ago, brand lenses were expensive for a reason. Third party offerings simply couldn’t match established makers, nor did they intend to. Sigma, Tokina and Tamron lenses were meant for the budget-minded and carried plenty of compromises as a result. These days, however, the situation is slowly changing. We now have the stabilized Tamron 24-70mm f/2.8 which, all in all, is as much of a rival to brand alternatives as anything. Then there’s the excellent Sigma 85mm f/1.4 lens and I see quite a few pros chose it over Nikon’s 85mm f/1.4G or Canon’s 85mm f/1.2L lens. Not the kind that would try and save money on gear they depend on daily… The previously mentioned Sigma 35mm f/1.4 seems pretty promising as well. They all feel solid and you could hardly mistake these lenses for anything other than professional optics. The best part is, they still cost less than brand lenses. All it takes for someone who wants to manufacture premium products is design a few standouts, one after another, and gain trust. It almost seems as if Sigma has been tirelessly making its way up to stand among the big names. They’ve come up with a few worthy lenses already, and the new 18-35mm f/1.8 might just be the next one.
What happens next? Well, either third party manufacturers will realize they can bump their prices up as quality rises, or brand manufacturers will be forced to lower their prices to stay competitive. What’s certain right now, though, is that brand manufacturers are trying to improve old designs and are reluctant to bring something new to the game, while certain third party companies seem to want to do both. Sigma 18-35mm f/1.8 lens is just one example. There’s also the versatile 120-300 f/2.8 lens (already in its third incarnation), while Tamron is the only one who can offer an optically stabilized 24-70mm f/2.8 workhorse zoom for full-frame cameras (Sony Alpha and Pentax DSLR shooters enjoy image stabilization with all lenses).
Third party lens manufacturers and Fujifilm are stirring water that has been still for too long, and coming up with some actual innovation. While Canon and Nikon try and outdo each other by updating old designs, Fujifilm, Sigma and other manufacturers are making their way forward. Someday, they may go past those who were seen as major systems and their sales will tumble, giving brand lenses a run for their money. The good thing is, photographers win either way. I’m not a very technical person, yet I can’t help but hope Fujifilm and Sigma keep it up. APS-C cameras need more fast lenses, be it zoom or prime. Technical or not, choice is a beautiful thing.