The Tamron 17-50/2.8 Di II VC is an update of the earlier, non stabilized Tamron 17-50/2.8 Di II. “VC” or Vibration Compensation is Tamron’s equivalent to Canon’s IS (Image Stabilization) and Nikon’s VR (Vibration Reduction). It uses a set of optical elements within the lens to compensate for camera movement via feed back from gyroscopic sensors.
The “Di II” designation indicates that the Tamron 17-50/2.8 Di II VC is a lens designed for use only with crop sensor cameras. The image circle of the lens fully covers an APS-C sized sensor, but does not cover a full frame (36mm x 24mm) sensor. Tamron Di II lenses will mount on full frame DSLR bodies (including full frame Canon EOS DSLRs), but severe vignetting of the image will result.
On an APS-C DSLR, a 17-50mm zoom gives the same angle of view as something like a 26-75mm would on a full frame Nikon or Sony camera, or a 27-80mm lens would on a Canon EOSDSLR. This means it covers the focal length range most used in landscape and travel photography, as well as being useful as a portrait lens. The fast f/2.8 aperture and optical stabilization means that the Tamron 17-50/2.8 Di II VC is also a good choice for hand held low light photography.
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The Tamron 17-50/2.8 Di II VC has a plastic barrel and a metal lens mount, The barrel finish is slightly textured and the markings are painted onto the barrel (not engraved). Focal length markings are given for 17mm, 24mm, 35mm and 50mm. There is a distance scale but no DOF markings.
The zoom ring is in the center of the lens barrel, is about 3cm wide and is rubberized. Zooming from 17 to 50mm requires an approximate 90° rotation of the ring. The zoom ring can be locked, but only in the 17mm position. The lens extends from a length of about 9.5cm at 17mm to 12.5cm at the 50mm setting.
The focus ring is narrower at about 1cm wide and also has a rubber finish. Close focus is 29cm and the ring requires about a 50° rotation to go from 29cm to infinity focus. The ring spins during autofocus, so you need to keep your fingers off it. To switch from autofocus to manual focus there is a small slide switch. Manual focus is smooth but undamped.
VC (Vibration Control) is turned on and off by a small slide switch next to the AF/MF switch.
The front element of the lens does not rotate during either zooming or focusing (focusing is internal), which makes the use of a polarizer more convenient.
The lens is supplied with a hood (petal style) which mounts on the lens using a bayonet fitting. The front of the lens is threaded for 72mm diameter filters.The lens cap is a “center squeeze” design which makes it easier to remove and replace with the lens hood mounted.
All testing was done with the Tamron 17-50/2.8 Di II VC mounted on a Canon EOS 40D DSLR. The comments below are based on both resolution chart tests and “real world” images.
At 17mm center sharpness and contrast are good, even wide open at f/2.8. The center does sharpen slightly on stopping down to f4, but f/2.8 performance is still very good. Stopping down further *to f/5.6 or f/8) makes very little difference. In the corners of the image the image is softer, especially at wide apertures, but by the standards of 17mm lenses, performance is still quite good. There is noticeable chromatic aberration at the edges of the frame. Distortion (barrel) is also quite noticeable at 17mm when there are straight lines near the edges of the frame.
In the mid section if the zoom range at 30mm center sharpness is still good at f/2.8. Again some improvement is seen by stopping down to f/4 but no significant further sharpening at f/5.6 and f/8. In the corners at f/2.8 the image is noticeably softer (and softer than at 17mm). Stopping down, even by 1/3 stop, improves matters and at f/4 the corner sharpness and contrast is much better. f/5.6 and f/8 bring only a very small improvement. Chromatic aberration is visible, but quite a bit lower than at 17mm. Distortion is minimal.
At the telephoto end of the zoom range (50mm), the center of the image shows some softness and lowered contrast when wide open at f/2.8. Again stopping down to f/4 makes a significant difference and further stopping down to f/5.6 and f/8 doesn’t really yield much more improvement. In the corners of the image there is some softness at f/2.8 and the image progressively sharpens at f/4, f/5.6 and f/8. Chromatic aberration and distortion are minimal.
Some vignetting is observed at all focal lengths when the lens is wide open. It’s not severe, amounting to something like 1 stop at the edges of the frame and a little more in the corners. Vignetting is significantly reduced by stopping down 1 stop to f/4.
Overall the Tamron 17-50/2.8 Di II yields very good center performance, especially when stopped down to f/4. For optimum performance across the whole frame stopping down to f/8 yields the best results.
Close focus is 0.29m, at which point the magnification at the 50mm focal length setting is 0.21×. That means that the area covered at closest focus by the 17-50/2.8 Di II VC mounted on an EOS 40D is about 71mm x 106mm (2.8″ × 4.2″)
Vibration Control (VC)
Tamron’s Vibration Control (VC) is analogous to Canon’s Image Stabilization (IS) and Nikon’s Vibration Reduction (VR). In all these systems angular rotation of the lens (left-right and up-down) is sensed by gyroscopic sensors and the lens compensates for this by moving a small lens group in the right direction and by the right amount to hold the image steady on the sensor.
By stabilizing the image, sharp results can be obtained when handholding the lens at shutter speeds which are much slower than would otherwise be possible. Up to 3-4 stops of stabilization can be obtained by some stabilized lenses. On a crop sensor camera, “conventional wisdom” suggests that you would normally need a shutter speed of around 1/80s to have a reasonable chance of a sharp handheld image. 3 stops of stabilization would allow an equal chance of sharpness at 1/10s and 4 stops would allow an equal chance at 1/5s.
I tested the VC by taking a series of handheld shots of a resolution test chart, first with VC off and the shutter speed set to 1/80s, then with VC on at shutter speeds of 1/20s, 1/10s and 1/5s. There was of course shot to shot variation at any shutter speed with VC on or off since the handheld sharpness is a matter of probability. What VC does is increase the probability of getting a sharp image, not guarantee one.
Shooting at the 50mm focal length setting I found that with VC off and a shutter speed of 1/80s, about 65% of my shots were acceptably sharp. That’s maybe not as sharp as they would be if I used a tripod, but 8×10 prints wouldn’t look blurred.
With VC turned on, I got about the same 65% “hit” rate with the shutter speed set to 1/10s. At 1/5s I still got some sharp shots, but the probability dropped to around 30%.
Based on these numbers I’d say that the VC on the Tamron 17-50/2.8 DiII VC provides somewhere around 3 stops of added stabilization (at least for me). On a good day and if you take several shots, you may be able to get sharp images 4 stops slower than “conventional wisdom” would suggest for a non-stabilized lens.
Of course the best route to sharp images at slow shutter speeds is still a tripod. However for those times when a tripod is impractical, stabilization is quite effective, especially if you don’t push your luck too far!
The Tamron 17-50/2.8 Di II VC is a viable alternative to the Canon EF-S 17-55 f/2.8 IS USM, (buy from Amazon) (review) at a price that’s about $450 lower. The image stabilization is very effective and overall performance is good, though not quite as good as the Canon lens, especially wide open and at the edges of the frame.
The Canon EF-S 17-55/2.8 IS USM is the most obvious similar lens. It’s very good but significantly more expensive. Sigma has a non-stabilized 18-50mm f/2.8 and Tamron has a non stabilized 17-50/2.8 which is similar, but not identical, in design to the VC lens but significantly less expensive. Tokina has a slightly wider 16-50mm/2.8 which is also non-stabilized.
Where to Buy
Photo.net’s partners have the Tamron lens in both Canon and Nikon mounts.
Tamron 17-50/2.8 DiII VC at 50mm. 1/25s at f/8, ISO 3200. An indoor shot in available light. I needed to stop down to f/8 to get a decent depth of field and ISO 3200 was the highest setting I had available. By using optical stabilization I was able to get a sharp handheld shot at 1/25s. In fact I could probably have lowered the ISO setting to 1600 or 800 and still shot a sharp image.
Tamron 17-50/2.8 DiII VC, 17mm 1/20 at f/8, ISO 3200. An indoor shot at the widest setting. Though there is a little barrel distortion, it’s not enough to seriously affect the image
Tamron 17-50/2.8 DiII VC, 17mm at f/2.8. This was shot wide open at 17mm. You can see that at this scale the image appears pretty sharp from edge to edge. Mild vignetting can be seen in the corners (easier to see in the upper corners).
Tamron 17-50/2.8 DiII VC at 50mm, 1/5s at f/11, ISO 1600. This still ;ife shot was done by available light. To get the required DOF I had to stop down to f/11 and I didn’t want to go over ISO 1600 because of noise issues. That meant my shutter speed as only 1/5s. Without stabilization (or a tripod) the chances of a sharp image would be virtually zero, but with stabilization things are pretty sharp
Tamron 17-50/2.8 DiII VC at 42mm. 1/25s at f/5.6, ISO 400. This shot of an old barn was taken around sunset when the light was low. At the aperture and ISO I wanted to use the shutter speed was 1/25s. At a focal length of 42mm, 1/25s is pretty unlikely to yield sharp handheld images. However with optical stabilization there’s a very high probability of a sharp image at 1/25s. Without VC I’d have either had to open up to f/4 or f/2.8 and/or boost the ISO to 800 or 1600.
Tamron 17-50/2.8 at 17mm, 1/2000s at f/2.8, ISO 100. At 17mm you can get an unusual perspective on things! Parts of the subject closer to the lens are enlarged, so be careful of using a 17mm setting for portraits unless you are looking for a special effect like this.
Tamron 17-50/2.8 at 50mm, 1/200s at f/2.8, ISO100. With the f/2.8 maximum aperture you can blur the background in portraits like this much more than you can with a slower lens, like an 18-55/3.5-5.6.