Lens Guides

Why Upgrading to the Sigma 17-50mm F2.8 EX DC OS HSM is a Wise Business Decision

The words “Fast F2.8 Standard Zoom” describing a lens may not have the same instant mystique and cachet as say,  “ultrawide” and “supertelephoto.” But for many a breed of photographer–wedding and location portrait specialists, for example–there’s no mistaking the importance of this workhorse lens. For APS-C shooters, the Sigma 17-50mm F2.8 EX DC OS HSM is a gigantic leap upwards in terms of overall performance compared to the variable aperture standard zoom kit lenses shipped with so many DSLRs.


17-50mm F2.8 EX DC OS HSM

Kit lenses are a great way to get started and learn, but when it comes to professional-quality results to satisfy the most discriminating photographers–not to mention their paying clients–the fast, constant-aperture standard zoom is the way to go. At first, it might seem redundant to purchase glass like the Sigma 17-50mm F2.8 EX DC OS HSM when there’s likely already a variable aperture kit lens in the bag that covers virtually the same focal range. And yes, the desire to add a longer, or wider, specialty lens is a strong urge, and maybe you’ll add one of those to your kit first. But whenever you do decide to swap the kit lens for a fast F2.8 standard zoom, you’ll immediately notice the advantages. You might say the difference between a variable aperture kit and a fast constant-aperture standard zoom is night and day; but I’ll choose to say it in terms of F/stops and bokeh.

The Sigma 17-50mm F2.8 EX DC OS HSM (fullframe equivalency: approximately 28-80mm on 1.6x APS-C cameras) zooms a bit wider, and a bit longer, than normal perspective while keeping the maximum aperture at a fast F2.8 all the while. And it captures this focal range for exceptional, professional-quality results. In fact, the testing lab, DXOMark.com states that its  “tests tend to prove that the Sigma 17-50mm F2.8 EX DC OS HSM Nikon is so good that it even surpasses its competitors from Nikon and Canon which are twice as expensive.”

This is a few stops slower than a fixed F1.4 standard prime, but what you gain in terms of compositional versatility without having to physically relocate to reframe is very well worth it when you are not in total control of the situation. In other words, with a quick rack of the zoom, you can quickly and easily frame much tighter or looser as a wedding ceremony unfolds without having to swap lenses, or shooting position. And this very well may make the difference between missing a key moment as you juggle gear, or causing a bit of ruckus as you race through the chapel to recompose!


The focal range of the Sigma 17-50mm F2.8 EX DC OS HSM goes a both a bit longer than and a bit wider than standard field of view when paired with an APS-C DSLR, like the Sigma SD1 we used in this demo. In the top image, the lens is zoomed all the way to 50mm and the lower image racked all the way back to 17mm. The tripod-mounted camera position remained exactly the same between both shots. Both images shot at maximum F2.8 aperture.

Variable aperture zooms always lose light-gathering ability as you zoom to longer focal lengths–that’s just how it works with optical physics. And the difference between F5.6 and F2.8 at maximum zoom is the difference between ISO 1600 and ISO 400, or between 1/15 second and 1/60 second. And that may very well be the difference between sharp, low-noise images, and motion-blurred shots with ugly shadow artifacts in the captured memories of a client.  (Remember, Optical Stabilizer can only minimize camera motions during capture, as explained in great depth here.)

Another key benefit of a constant-aperture zoom is that there’s no shift of exposure or overriding of settings as you zoom, which happens with variable aperture lenses. So, if you are in metered manual mode, and you’ve locked in an exposure off a bride’s blushing cheek, you can easily zoom in or out without seriously impacting your creative decisions. If you’ve decided on 1/100 @ F2.8 at 17mm and then want to quickly zoom in for a magic expression, you’ll still get 1/100 @ F2.8 at 50mm. Try the same thing with an 18-55mm F3.5-5.6 kit lens @ 1/80 at 18mm and zoom in to 55mm @ F5.6 and your shutter speed is going to have to drop a few stops, or the ISO will have to climb. Or depending on your particular camera settings, you may wind up underexposing the shot by a few stops if you zoom in and it keeps with your manual decisions.  There’s a workaround, which is to limit your maximum aperture to the variable aperture maximum, but this isn’t necessarily a great way to go.

And of course, the same holds true with lighting. If you’ve got a couple of non-TTL studio heads on light stands, you’re going to want to lock in your exposure settings on your camera. And if you’ve got a kit variable aperture standard zoom on your camera, that limits you to making sure you’re stopped down to the maximum value at telephoto to make sure you don’t seriously blow out the exposures as you go wider. (In other words, when shooting with studio strobes with a variable aperture zoom, you’ve got to make the lens act as though it is only capable of it maximum telephoto aperture at all focal lengths…to make it act like a much slower constant-aperture zoom!)

Here, we are near close-focusing distance, at 17mm, at F2.8. Notice how there is very nice subject and background separation, with a crisp zone of focus on me and the camera. The repetitive struts and supports of the trestle bridge are identifiable, but nicely softened.
And here, we kept both cameras in exactly the same positions, but zoomed the 17-50mm all the way in to 50mm, again near closest focus distance with both shots at F2.8. Notice both how much more shallow the zone of sharp focus is, and how much softer the background elements are.

The focal range of the standard zoom lens is great for capturing people in the environment. You can go wider to make it more of an overall scene-setting shot, and then zoom in to tighten the composition and soften the bokeh even more while still painting the environment’s signature elements in the background–soft, with lovely separation, but still recognizable. Sometimes turning the background to pure abstractions is a good thing, but, many clients will actually want to be able to recognize the location they selected for their shoot!  And while the 28mm equivalent widest angle might not be the widest lens out there by a wide margin, there’s very little body image distortion at the 17mm focal length, even when the subject is very close to the edge of the frame and near the camera. Serious subject distortion may work well for skateboard action shots, but when there’s brides involved, not so much!


The Sigma 17-50mm F2.8 EX DC OS HSM is a top-quality tool for working pros, as well as enthusiasts who demand the utmost in image quality in a fast standard zoom lens.

The Sigma 17-50mm F2.8 EX DC OS HSM is also a fantastic lens for landscape and documentary photography, too! Check out the fantastic images Sigma Pro David Fitzsimmons created with this fast standard zoom in this Lens Exploration blog posting.



Comments (16)
  1. Susan says:

    I have this lens and it is indeed a very nice lens. Great color reproduction. One draw back, the manual focussing ring is a little loose, should be a bit stiffer.

  2. Ron says:

    I am confused. The specs say “For use with smaller chip APS-c digital cameras only” but the pictures are showing it on a full frame Canon 5D. Were the pictures taken with the 5D or an APS-c size sensor?

  3. sigmaauthor says:

    Ron. The capturing lens is the Sigma 17-50mm F2.8 paired with a Sigma SD1. The lens on the camera in the images of me on the bridge is a Sigma 15mm F2.8 EX DG Fisheye paired with the Canon EOS 5D. Didn’t mean to confuse anyone. We’ll clarify this info in the captions!

  4. Angelo says:

    I got this lens as a replacement for my kit lens and my 50mm f/1.8. It’s truly an amazing lens and a great upgrade. The constant aperture in the entire range is really a great thing!

  5. D Sand says:

    I just got my EOS copy today. So far so good. I’ve been really needing faster glass.

    I am a bit flabbergasted after snapping a quick shot of our cat I showed my wife and she said it looked like a professional picture and very nice……. I didn’t expect to hear that. She usually disinterested at best.
    Well that sounded corny but anyways.

    Many reviews claim the hood is loose. I thought woops mine was also, that is until I gave it a extra bit of torque and it snugged up nice and tight.

  6. Reidar Henriksen says:

    My lens is Sigma DC 18-50mm 1:2.8 EX Macro HSM. Is that the same lens?
    My camera is Nikon D90! Do I have a 28-70mm on my camera?

  7. glen says:

    Is this a DX lens or FX? Will it cover Full-Frame and film?

  8. sigmaauthor says:

    Glen, Sigma lenses that are full-frame are designated “DG.” Sigma Lenses that work on cropped sensor DSLRs are designated “DC”. You can remember which is which by remembering that the DC lenses are designed for APS-C cameras.

    So, no, this lens is not designed for a 35mm full-frame image circle.

  9. Rommel says:

    i’ve had this lens for more than a year now. I am very satisfied with it: it is very sharp, focus is very reliable and reasonably fast, and the OS works well. if you still have any doubts about the capabilities of this lens, borrow one from a friend who has one or go to a store that has it and take a few test shots with your camera. I did. This is why I have one.

  10. Rommel says:

    one more thing, it costs much less than the equivalent Nikon lens. that, plus its image quality should be enough to convince you that this lens is a winner.

  11. Steve C says:

    I find this lens very good for shooting video with my Sony a77. The constant aperture lets me zoom in and out on moving subjects without concerns about changing settings. Love the lens.

  12. Steve says:

    Have had it for a year! Used it from a 60D & now a 7D & plan on having it for years to come unless i decide to go FF! Great compliment to my 70-200 2.8 os & 85mm 1.4:) Great walk around lens:))))

  13. DARBI says:

    I have a Nikon D40 and i want to change the lens with sigma 18-250mm f3.5-6.3 DC (OS) MACRO HSM do you think ican use that to Niko D40

  14. I do mostly weddings and I use the Nikon D7100. After looking at options to step up from the 18-140 I came across this lens and decided to go with it. Woow it has significantly impacted the quality of my work, I don’t miss not having a full frame camera. Plus it’s well built but not too heavy. For me the Nikon 24-70 apart from being very expensive would strain my hand too much as I’m having some issues. This lens is a decent enough weight. Loooove it Sigma thanks.

  15. Since buying this lens last December my work has been totally transformed. I wanted to actually upgrade to a full frame since using the D7100 but my plans got messed up. My next option was to improve on what I had so I researched and since I needed to also improve my off camera flash equipment I needed the best option I could afford. Wow we this lens is one or my best investment yet. It makes the D7100 shine better than before and honestly I don’t miss not having a full frame. I shoot lots of weddings and now my work stands up well against my colleagues D610. God bless you Sigma keep up the good job.

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