Sigma 50-150mm f/2.8 Lens Review


The Other Telephoto(s)

Copyright 2012 Thom Hogan

Older Non-OS Version
Newer OS Version
Lens Formula
18 elements in 14 groups; 4 SLD low dispersion elements.
21 elements in 15 groups; 6 SLD low dispersion elements.
Other Features
HSM (AF-S equivalent) focus, Internal focus, 67mm filter size. Comes with petal hood, 9-blade aperture. Focuses to 3'4" (1m).
Optical stabilization, HSM (AF-S equivalent) focus, Internal focus, 77mm filter size. Comes with petal hood, 9-blade aperture. Integrated tripod collar. Focuses to 2'8" (.8m).
Size & Weight
About 5.2" (132mm) long from mount, 27.5 ounces (780g).
About 7.8" (198mm) long from mount, 47.3 ounces (1340g).
Price
NA
US$1000

The Basics
Sometimes good ideas go bad. The Sigma 50-150mm f/2.8 is an example of that. There are two versions of this lens: the original 50-150mm f/2.8, and the 50-150mm f/2.8 OS, which adds a rotating tripod collar and optical stabilization.

Somewhere between the original and the replacement, we lost as much as we gained. Or, actually, we gained some things we didn't want or need: weight and size.

I'm going to speak mostly about the original 50-150mm f/2.8, as that's what I used for a long time, and after a brief encounter, I've returned the OS version. It's not that the OS version is bad, it's that it begins to violate the premise of DX, which I'll get to.

The original Sigma is a rather non-descript lens. It has a fairly plain barrel with two large rings that dominate it. Indeed, the barrel is mostly rings. The ring closest to the camera is the zoom ring, marked at 50, 70, 100, and 150mm. The forward ring is the focus ring. Between the rings is a focus distance scale, which isn't marked with DOF or IR markings.

Internally, the original lens features Sigma's HSM focus motor and internal focusing. Basically you can think of this as a 75-225mm equivalent fast focusing and fast aperture lens.

The newer OS version of the lens adds a great deal of bulk and weight. It's grown over two inches in length, and added a pound of weight. For all that growth in physical attributes, you basically add optical stabilization, a rotating tripod collar, and an even more complex optical formula that rivals Nikon's 70-200mm. Other than the fact that at US$1000 the new Sigma OS is cheaper than a 70-200mm, the size is a big turn off. Enough so that I decided very quickly not to keep the lens. But you want to know about the other physical attributes: the zoom ring is now up front and still large, the focus ring is closer to the camera and quite small. There's still a distance scale, but still no DOF or IR markings.

The original version uses 67mm filters, the new one 77mm, and both are made in Japan.

Handling
The original 50-150mm isn't a large lens, nor is it overly heavy for its size. It balances on the front of my DX bodies very nicely. Indeed, that's the point of having a 70-200mm DX equivalent: it scales down nicely from the big 70-200mm the big boys use. In the image below, the Sigma 50-150mm is on the left, the Nikkor 70-200mm (with tripod foot removed) is on the right. This isn't a composite image; as with all of my side-by-side images it's a real side-by-side shot:

Copyright 2012 Thom Hogan

Both rings on my original 50-150mm are stiff but smooth, pretty much the way I like them. Not old best-of-class smooth, but smooth enough so there are no hitches as I turn the rings, plus just enough resistance to keep me from easily overshooting what I want to do. The original lens does not change length while zooming or focusing.

The lack of a tripod collar on the original is probably the only ding I'd make, and even then I'm not sure it's a big demerit. On a small DX body the original is very handholdable, though the lack of OS means you have to pay attention to technique--sloppy shooters need not apply with this lens, as at 150mm you really need to be at least at 1/250, and if you can't handhold that shutter speed...

The new 50-150mm is a different beast. It's just bigger. Big enough that it rivals the Nikkor 70-200mm. Ironically, the added rotating tripod collar gets in the way of handholding, which is what the OS is there to help you with. The new OS version also changes length a bit with zoom. The rings were smooth; better than the original, so that's a plus. But I don't want "large" on a DX body. It's like when I used to wear an XL t-shirt but really should have been wearing a medium: it's a mismatch.

Performance
Since I determined very early on that I was going to return the 50-150mm OS version, I didn't take the hours of time necessary to run it through the full set of tests. I didn't notice any dramatic optical changes with the new lens over the older one in my short time with it. The following statements apply only to the original 50-150mm without OS.

Autofocus
: I've always liked Sigma's HSM. It's fast and reasonably silent (a bit more chattery than Nikon's AF-S, but not enough to make a difference, IMHO). This is a telephoto lens, so it tends to be a little slower in making huge focus moves (e.g. near to infinity) than the wide angle or mid-range focal length Sigmas, but it's still acceptably fast, even on my D3200. The shallow DOF of a telephoto means that you need to watch out for low contrast and especially low contrast in low light subjects, as I found a number of instances where the lens simply didn't find focus in those cases. But they tend to be extreme, and they're worse on the lower end bodies than they are on the higher end DX bodies. For example, on my D3200 and non-central sensors, I was having trouble with dark, low contrast, off center objects at ISO 100, 1/4, f/2.8. That's a little sooner than I experience with the high-end Nikon bodies and Nikkor AF-S lenses. Not enough to be worrisome, but something to keep in mind.

Sharpness: Here's the real shame. The original 50-150mm is optically pretty good. At 50mm there's nothing really to complain about: it is center-to-edge sharp even wide open. Even halfway through the zoom range it still has similar performance, though the edges do drop a bit. At 150mm, it's sharp in the center and weak in the corners at f/2.8. Not terrrible, but still clearly soft. This improves to very usable corners by f/5.6.

Indeed, the way I'd characterise this lens is as follows: 50-100mm: don't really worry about it. 100-150mm: if corners are an issue, stop down, and if overall sharpness is an issue, stop down. Even one stop raises the bar quickly for the optics on this lens, two stops puts you about at the max you're going to get out of it.

Frankly, the original Sigma's optics were pretty refreshing: the behavior is simple and predictable. Indeed, almost exactly as you'd guess. No strange things happen as you zoom part way, then zoom a little more (I'm looking at you, 18-300mm).

But there's one caveat: close focus. At it's close focus point, this lens clearly doesn't perform like it does at 10' (3m). Everything is weaker in MTF overall, though the same pattern of 50mm being better than 100mm being better than 150mm is followed. Center and corners are both too soft for my taste at minimum focus distance.

Light falloff: As you might guess from the above, light falloff follows the same pattern: maybe a half stop wide open from 50-100mm, about a full stop by the time you get to 150mm. Stopping down even one stop pretty much puts everything in a comfortable zone, and two stops puts you into the "ignore the vignetting" zone.

Chromatic aberration: Well corrected, overall. There's minimal chromatic abberation wide open. Strangely, 150mm produces worse results as you stop down (typically chromatic aberration improves with smaller apertures). Still not enough to worry about, but if you're trying to minimize chromatic aberration and get optical sharpness, you're in a slight bit of a bind at 150mm (hint: use f/4).

Flare: The hood is deep, and unlike the Tokina, I couldn't force it to go crazy on backlit scenes. Very good flare performance overall.

Distortion: About 1% barrel distortion at 50mm, which flips to about 1% pin cushion distortion by 100mm, then degrades perhaps another half percent by 150mm.

Bokeh: Not bad. I see a little longitunal aberration wide open (typified by cyan/green edges), and out of focus circles are a little mishapen.

Overall, I like the original 50-150mm. Indeed, it's the only purely DX telephoto I've kept in my gear locker.

The following comments apply to the original 50-150mm:

Drawbacks

  • 150mm is weak. Corners especially suffer, and watch out for close focus.
  • No OS. Would have been nice in this design, but Sigma opted to give us something else.

Positives

  • Nicely scaled 70-200. Other than some weakness at 150mm, Sigma did a good job of scaling down the workhorse telephoto zoom.
  • Focuses well. With the exception of very low contrast and low light situations, the lens snaps focus quickly and precisely.
 
Quick Evaluation

features
performance
build
value

The ratings above are for the original 50-150mm.

You'll note that I don't have a recommendation. That's two-fold. The OS vesion of this lens has grown to a size that makes it decidedly non-DX like. Most users would probably just use a 70-200mm or 80-200mm and enjoy the extra reach when a lens gets as big and heavy as the OS version. The older non-OS version is sometimes available used, but Nikon's habit of tweaking new camera bodies makes it a little risky to rely upon older third party lenses that reverse engineer things like AF-S communications. At the moment the older version seems to work without issues on all the current Nikon DX bodies, but there's no guarantee of that moving forward, and Sigma is not likely to re-chip an out of production lens.

Limitations


The 50-150mm lens has limitations you need to be aware of:

Converters: use Sigma HSM converters for best results.

G: Since this is a DX lens, it's not likely that you'd mount it on an older 35mm body that can't handle the lack of aperture ring or makes restrictions because it is missing.

Coverage Area: produces a small corner vignette on FX bodies at all focal lengths. The lens is usable in 5:4 and 1.2x frame sizes on FX bodies, and if you're willing to crop the exterme corners, it is usable on FX cameras.

Version of Review:
10/16/2012: initial post.






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