Tamron 17-50mm f/2.8 SP XR


The lower-priced mid-range alternative for DX shooters.

 


Copyright 2007 Thom Hogan
Tamron 17-50mm mounted on a Fujifilm S5 Pro body. Note the nice balance in size.

Lens Formula
16 elements in 13 groups; 2 aspheric, 1 XR, and 1 LD elements.
Other Features
Internal focus, 67mm filter size. Comes with hood. Focuses to .9 ft (0.27m).
Size and Weight
About 82mm long, 15.3 ounces (434g).
Price
US$449 (street 11/07)

The Basics

With the Nikkor 17-55mm f/2.8G DX selling for US$1199 and with some worried that the appearance of the FX frame size meaning fewer high-end DX bodies in the future, a lot of D200 and D300 shooters are looking for a lower priced alternative that's optically as good. The US$449 Tamron 17-50mm f/2.8 is the usual suspect, and the subject of this review.

With the smaller sensor size of most of the Nikon digital bodies (D2 series, D200/D300, the Fujifilm bodies, etc.), the angle of view for a 17mm focal length is effectively that of a ~26mm lens on a 35mm SLR, and at the 50mm end we get equivalent to 75mm. Thus, a 17-50mm lens would be the mid-range focal length equivalent for DX of a 26-75mm lens for the FX format. That's close enough to the common 24-70mm length that both Nikon and Canon offer for full frame, that I'll consider them equivalent.

Before continuing, I should note that, while I carry this focal range with me much of the time, I very rarely use it (indeed, I had to up my use of it to finish this test, which has been going on for some time). That's because one of the key elements of successful photography is dealing with "depth." The real reason pros gravitate towards the wider and more telephoto focal lengths doesn't have as much to do with angle of view as it has to do with the ability to exaggerate the compression or expansion of visual depth in an image. Because we're taking three-dimensional objects and producing them as two-dimensional ones in our photos, "normal" depth cues actually tend to make the resulting images look a bit flat. Especially when compared to ones that were taken with more extreme focal lengths and specifically targeted at exaggerating depth cues. Still, a large proportion of users end up with mid-range zooms in their bag, and use them regularly.

As I write this, we have only three mid-range lenses that qualify as high-end and are targeted at the DX frame size: the Nikkor 17-55mm f/2.8, the Sigma 18-50mm f/2.8, and the subject of this review, the Tamron 17-50mm f/2.8. I've used the Nikkor and Tamron extensively, the Sigma only in passing.

Compared to the Nikkor, the Tamron is smaller and lighter, and significantly so. This, in addition to its price, is the key factor that tends to attract Nikon DSLR users to it.
Copyright 2007 Thom Hogan The Nikkor 17-55mm on the left, the Tamron 17-50mm on the right. As you can see, there is a considerable size difference between these lenses in every dimension.

The 17-50mm focal range gives you diagonal angle of views from 32 to 79 degrees on a D200 or other similar DX sensor body; that's effectively the same as using an 26-75mm lens on a 35mm film or FX sensor body. For some users, that's the stay-on-camera range they have been looking for. For me, I find myself at the two extreme focal lengths of this lens all the time.

This is a two ring design; unlike some recent Nikkors, the zoom ring is nearer the camera than the focus ring (i.e. the traditional position on zoom lenses). The focus ring is about at the halfway point when the lens is zoomed in, near the front when the lens is zoomed out. The lens has a distance scale, but with no depth of field or infrared markings.

Optically, the Tamron lens is surprisingly more complex than the Nikkor 17-55mm. In general, more elements/groups in an optical design are avoided because this makes the lens more prone to flare, amongst other things.

The DA09 hood supplied with the lens is the bayonet type butterfly style. It can be reversed onto the lens for carrying, but it adds diameter to lens when you do so (and covers the focus ring, so you won't be tempted to use it this way ;~). It's also a bit "deeper" than many butterfly hoods; it covers the front element decently.

You get regular screw-drive focusing with this lens, as opposed to AF-S, and that'll take you down to a little under one foot (.27m). The supplied lens cap is a pinch-front type similar to Nikon's most recent lens caps.

 

Handling

Let's get the bad out of the way first: the build quality of the Tamron lens isn't up to the standard of the Nikkor. Not even close. The Tamron has more use of plastics and feels more sloppy in several aspects than does my Nikkor 17-55mm: for example, when extended, the front of the lens has a slight bit of wobble to it.

The zoom ring is wide and feels better in turning than many zoom lenses I've used lately. There's no "hitch" in the turn like you feel with some lenses. An issue for me is that it's almost a full quarter turn from one end to the other, despite the short focal range, which if you're using a finger roll technique works out to two or three "rolls." But as with the Nikkor, I quickly adjusted to it and stopped noticing after a few minutes of use. If this is the main lens you use, I'd be surprised if you don't adjust, too.

While there's a difference in "feel" of the two rings, the focus ring is too close to the zoom ring for you to distinguish the two solely by feel. Unlike a lot of focus rings, the Tamron's feels smooth, though a little too eager to turn (I'd like just a tiny bit more resistance). But the bad news is that this isn't an AF-S lens, so the only time you'll be touching that focus ring is if you shift to manual focus. The focus ring does its job in just over one-eighth of a turn, which some will like (I do) and some won't (fine tuning focus can be slightly more difficult).

Focal length changes slightly when you're shooting at very close distances. As with most modern lenses, you should be focusing after framing, so I don't see this as a big deal.

The lens balances very nicely on a D200 or D300 (or S5 Pro for you Fujifilm users). Nor does it stick out as much as the Nikkor. Moreover, the lens stays short at its shortest focal, unlike the Nikkor.

Performance

Everyone's probably scrolled past all my other comments to get down to this section, so let's cut to the chase: this is a very good lens in almost every respect; but it's not perfect.

Distortion: The lens has very visible barrel distortion at 17mm (about 3% by my measurement). There's a tiny bit of bow-tie component to the barrel effect, but the majority is correctable via simple methods. By 24mm, this is all but gone (I can't measure it reliably it's so low). A tiny bit of pincushion distortion appears as you move to longer focal lengths than 24mm, but generally well under 1%, so most people won't have any issue with that. Even at 50mm the pincushioning distortion is still a bit under 1%. (For those just joining us, anything under 1% tends to be invisible in pictures except to pixel peepers.)

Sharpness: I was surprised at how well this lens performed, actually. Moreover, optically it appears best around f/5.6, which is quite good for a fast, complex lens like this. Center performance is best in the wider focal range (~17-28mm) with a very slight drop-off by 50mm. Corner performance is about the opposite: best at the mid-range apertures at the longest focal length (and almost the same as the center by f/8), visibly less so at the wide end.

While the central area of the frame is almost always excellent on any current DX sensor camera, the corner performance wide open is only what I'd characterize as "good." Indeed, in the central regions, this lens is about as good as it gets on the 10mp and 12mp DX cameras, even at f/2.8. By f/5.6 at almost any focal length, I'd call the performance of this lens "excellent" (though the corners will still be a tad softer than "excellent" at 17mm). Here's my new short-hand cheat sheet for sharpness:
  Wide Open (f/2.8) Optimal Aperture (f/5.6)
Corner
Center
Corner
Center
17mm
good
excellent
very good
excellent
24mm
very good
excellent
very good
excellent
35mm
very good
excellent
excellent
excellent
50mm
excellent
excellent
excellent
excellent

Overall, I'd put this lens in the same category as the Nikkor for sharpness, though I did feel that the Nikkor produced a bit more contrast, especially at the wide end.

Aberrations: A bit of a mixed bag here. At 50mm you can pretty much ignore them. Ditto for the mid-range focal lengths once you get to f/5.6. At 17mm, however, I still see visible aberrations at f/5.6, though they're not obnoxious. At wider apertures, you will definitely want to consider doing some sort of chromatic aberration reduction in software for your 17mm shots, as I see obvious problems there.

Light falloff: Well, you can't win them all. This lens has pronounced falloff at f/2.8, easily over a stop in the corners at all focal lengths. Stopping down to even f/4 dramatically lowers this, by over half at all focal lengths except perhaps 17mm. By f/5.6 falloff is well controlled at all focal lengths except 17mm. Unfortunately, 17mm never really seems to get better than about a half stop of falloff in the corners, no matter what aperture I use within the diffraction limits (f/13 on the D200 on which I did most of the testing for this lens). This, coupled with the softer corner performance at the wide end, are the Achilles heel for the lens and the reason why I'm undecided whether it stays in my kit. After all, I'm typically always at the wide end of this lens. Thus I have to worry about the corners, even at small apertures. Fortunately, a lot of recent software can deal with vignetting--Capture NX and Lightroom in particular--which is why this lens is still in my bag much of the time (it after all, is smaller and lighter than the only alternative I'd consider at the moment).

Focus: For a lens without AF-S, focus is actually fast and hunt-free. I suspect that the focusing elements in this lens don't move much (note the short throw on the focus ring).

Flare: I had no obvious problems with this lens (I should note that I always used the supplied hood). In direct comparisons with the Nikkor, I did sense a very small bit less contrast overall to images shot towards the sun, but not enough to worry about.

Flash exposures: It appears that the lens is reporting the wrong focus distance value to the camera, which causes the camera to tend to overexpose the flash in TTL BL mode. Due to the way light works and the incorrect values that are reported, the overexposure will be more obvious the closer your subject is to the camera. I didn't see this at first because I typically shoot in Standard TTL and at longer flash distances for my testing.

Overall: For the price, the Tamron performs well, though not perfectly. The primary trait that stands out is the sharpness, which is quite good and in the arena of that Nikkor that costs more than twice as much. If you're in the middle of this lens' focal range most of the time, and at mid-range apertures, there's very little to complain about. At the telephoto end, there's little to complain about at any aperture. It's that wide end that keeps this lens from being a five-star lens: the corners are going to be darker and softer than the center at any aperture, and have visible chromatic aberration in them if you're shooting at wide apertures. That could be enough to put some off this otherwise fine lens.

Wither the Sigma 18-50mm? I haven't used it enough to review it, but I have used it enough to know that it doesn't beat the Tamron.

Wither the Tokina 16-50mm? Again, I haven't used it enough to review. It's a larger and heavier lens.

Drawbacks

  • Corners at 17mm. Vignetting, softness, and aberrations, oh my.
  • Not AF-S. While the focus is nearly AF-S fast, the big issue is that you can't override focus manually.

Positives

  • Sharp as a knife, mostly. Outside the corners at 17mm and at 24mm wide open, this lens posts resolution numbers on my D200 that are about as good as they get.
  • The affordable 28-80mm for DX users. Considering the price differential between this and the Nikkor 17-55mm, there's little tradeoff being made. Indeed, this lens is smaller and lighter than the Nikkor, yet except at 17mm, holds its own against that lens.
 
Quick Evaluation


Highly recommended
; a low cost alternative to an expensive Nikkor.

features
performance
build
value

No VR and no AF-S are the primary liabilities of this lens, as is its performance at 17mm. Other than that, it's competent across the board.

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Version of Review:
11/3/07: initial post.
11/6/07: typo corrections
11/27/07: update flash, competition




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