Fstoppers Reviews the Sigma 17-70mm f/2.8-4 Contemporary Lens

Variable aperture lenses are generally scoffed at by anyone who has been shooting for a few years, myself included. That said, collectively variable aperture lenses probably make up a vast number of sales for lens manufacturers. They aren’t necessarily bad lenses, but it can be tricky to select the quality from the lousy. So how does Sigma’s second lens that carries its new design, the 17-70mm f/2.8-4 lens, fare? Actually, really well.

The very first lens I ever owned was a Sigma 28-70mm f/2.8-4 (seen below next to the 17-70mm), a lens that's not even in production anymore. It was cheap, light, small, opened up to f/2.8 and it worked well for me for years until I was making enough money to invest in better glass. What it wasn’t was super sharp or “high performance” in really any category. But that didn’t matter. It was what I wanted and it worked really well for years. When I saw the new version of the 17-70mm come onto the market, it evoked a lot of sentimental feelings. If I was again back in my past looking at lenses, I would no doubt have my eyes on this lens. But with those sentimental thoughts were also memories where performance was just about at par. Nothing special. Average. In the my mindset of years ago, this wouldn’t have been a big deal. But where I am now, I expect more out of a lens. Because of those expectations, I was pretty sure that I wasn’t going to be as happy with the new 17-70mm as I once was with my original 28-70mm. Times change, and I’m not the photographer I once was. I have grown to expect more. I did not expect this lens to deliver to that grown expectation.

But I have to say, I was pretty happy with how this lens performed.

I’m sure many of you are crying foul to my apparent Sigma fanboyism, and I’m not going to say I don’t really love Sigma right now (that would be an outright lie). I will say that when you take a look at the image results from my tests you will be hard pressed to not take my side on this one. The 17-70mm really performed well, especially given expectations and other similar lenses and price point. It will only set you back $500.

Let’s start with sharpness. As expected, wide at 17mm it wasn’t the sharpest at f/2.8. It’s not blurry by any means, but it’s not dazzlingly sharp either. On a 10 scale, I would rate it about a 5. But as we crept up between f/4 and f/10, this lens was quite satisfyingly sharp, and 8 or 9 on my 10 scale. Through f/22 it was way more than acceptable. Though at f/22 you will see blurring similar to what is seen at f/2.8, at the surrounding stops it still performed great, about 6 or 7 on my scale. You can judge for yourself in the samples below. In order left to right: f/2.8, 5.6, 8, 11, 16, and 22.

When we zoom in to 70mm, sharpness looks to improve in a regular fashion as the aperture closes. At f/4 (widest at this focal length) it’s not quite as sharp as it was wide at 17mm at the same aperture, but it’s acceptable. As we close down the aperture, the image continues to get sharper. It’s bang-on sharp past f/10 and keeps getting better.

Honestly, I wish the sharpness was more consistent but when it’s sharp, it’s really sharp. I know that in many situations, I’ll be as wide open as the lens can go and that’s unfortunately not where this lines shines. However if you’re traveling a lot (which is common for those who buy lenses like the 17-70mm) you will likely be closed down most of the time for landscape shots. In those cases, this lens will shine.

Again, judge for yourself from the sample below. In order left to right:

Just like with the last few lenses Sigma has released, the autofocus is extremely reliable. It rarely missed focus and it’s super quick. The only times it racked in and out looking for a subject was in very dark situations or on highly reflective surfaces, neither situation uncommon for any lens, especially not a lens in this price range/class.

I also like how the minimum focusing distance is only 8.66 inches, increasing the usability of this lens. You don’t expect this lens to be macro and that makes for a really pleasant surprise while shooting. Being macro shows how Sigma wanted this lens be as close to a do-all lens as possible, and it’s making a strong case for being called that. The lens is almost adaptive, doing anything you really need it to in the field.

There was no chromatic aberration, and I put it through some crazy situations to try and get some to appear. This was probably the most impressive aspect of the lens. Have no aberration at any focal length or aperture is extremely rare. There was very little vignetting when at 17mm, basically none when out at 70mm.

This lens comes equipped with Optical Stabilization, and I gauge it to be about as good as what you can expect from Nikon or Canon’s versions. It’s going to be very helpful for those of you shooting in low light and also video. It’s not quite as good as Tamron’s vibration compensation, but neither are the image stabilizers from Canon or Nikon, so I can’t hold that against Sigma. Besides, it has a lot of other factors going for it.

The build quality of this lens is very similar to the 35mm f/1.4, but it’s not quite as nice. The 35mm has a lot of metal on the exterior, which made for a lens that just felt sturdy. The 17-70mm looks really nice before you hold it, but once it is in your hands you will notice it has no metal on the outside which I imagine was done to keep the prices low. Not to fear though, as it still functions like I wanted. Nothing is loose when racking the focal length in and out. Being without the metal parts, this lens is very light, which is great for travel. It feels firm and strong. The lens hood still snaps on with a firm and gratifying “click.” All in all, it’s no 35mm but it’s no slouch either. As far as how it stacks up to lenses in its class, it’s easily one of the better in terms of look and feel. I think that trading metal exterior parts for weight and price works. In this category, it was the right decision.

It’s wider than the most popular focal range (which is 24-70mm) and that lets it compensate for the APS-C sensor at 17mm, making it actually 25mm or so at its widest. That’s pretty darn good in my book. Close enough to being an actual 24-70mm on a crop sensor, and very well priced.

What I liked:
Auto focus performance
Ease of use
Versatility
Macro
Price

What could use improvement:
Sharpness at widest apertures
Consistent sharpness
Variable aperture

I really wasn’t expecting to like this lens. Aside from being easy on the eyes (it is a very pretty lens), I was prepared to shrug it off and move on. But after using it, I’m really surprised with how well it performed especially given its price point. Anyone looking to grab a do-it-all lens for a low price, consider the Sigma at the top of your list. It never really fails in any one place and any stumbles it may have are negligible, especially when compared to other lenses in its class. It may have issues with sharpness when you're zoomed in at more open apertures, but at it's widest focal length it performs pretty darn good. Add to that the complete lack of chromatic aberration and negligible vignetting and you have a pretty solid lens.

If you have an APS-C sensor in your camera and are looking for an affordable yet quality lens you'll hardly ever take off that body as you tote it around for the next couple years, you'll be hard pressed to find a better option than the Sigma 17-70mm f/2.8-4 Macro OS HSM.