Do you entertain yourself by reading lens reviews and spend hours on eBay looking for the ultimate lens? Do you have the desire to own every lens ever made? Does your camera bag weigh more than you do? Then you may be a good candidate to read this article.
|Tamron® SP AF17-50mm F/2.8 Lens on a Nikon D300s|
Collecting lenses can be like collecting used Boeing 747 airplanes. Lenses are just plain expensive! Yet life is best when our camera bags are heavy with glass. We may not need them today, but they're there when we do.
With lens buying habits that approach national debt levels, it's a good idea to save money, as long as quality isn't compromised. Nikkors® have been my choice for most of my photographic life—and will continue to be. Recently, though, aftermarket lens manufacturers have released some very desirable lenses that cost significantly less. Less is better when it comes to cost!
|Tamron® SP AF17-50mm F/2.8 XR Di-II VC LD Aspherical (IF) Lens|
One of my favorites is the Tamron® SP AF17-50mm F/2.8 XR Di-II VC LD Aspherical (IF). Although the name is longer than the lens itself, it performs—in certain ways—even better than some of my beloved Nikkors. The Tamron "SP" designation marks their best lenses, with resulting excellence in glass and build quality. The Tamron costs about $650 USD. A comparable Nikon-brand lens, such as the AF-S Nikkor 17-55mm F2.8 can cost over twice as much. Of course, the Nikkor lens has a stronger metal build, and you pay for that. The Tamron lens barrel is made of "high-impact" polycarbonate, so it can be lighter yet still maintain excellent strength for daily use.
Let me tell you about my experiences with this lens.
Not long after the newest version of the lens was released, I was given an opportunity by Nikonians.org and Tamron to use one for a few weeks. For most of December 2009, this lens was on my Nikon D300s. I used it as the "portrait" lens while shooting a wedding's formal groups shots, and as a "save my buns" lens, when shooting the reception lit by white Christmas tree lights. Do you know how hard it is for a camera to focus on people dancing by candlelight? The Tamron's wide F2.8 constant aperture was a big help.
Tamron Vibration Compensation (VC)
In other words, not only does it match the Nikkor's up/down and left/right capability, but it also adds diagonal compensation. Imagine placing an x on top of a + sign, and you'll see how the VC system can handle camera movements in more directions, up/down, left/right, and diagonally. For this reason, the Tamron does not have a Normal/Active switch, like the newer Nikkor VR lenses. It handles the other angles automatically and doesn't need one.
Here's information provided by Tamron technical representative Rob Moody:
"Other two-coil systems on the market have to compensate for diagonal movement by triangulating or computing through the body. This is what produces the floating or drifting effect you experience when the stabilization is engaged in other manufacturers lenses. The new three-coil system eliminates this process by using an additional or third coil to compensate for diagonal movement."
When I've depended on VR while using my Nikkors—such as when a tripod is not feasible—I've always allowed a second to let the VR "take hold" before taking the picture. Otherwise background objects can have a weird repeating blur when the VR is not fully locked when the picture is taken. If you've used VR for any length of time, you may know what I mean. Things on the edges of the image can look really weird, like a failed Photoshop clone effect, even while the subject is sharp. I attribute this to the VR system not fully acquiring "lockdown," in a sense, before the shutter is released.
Using the Tamron's VC system, I didn't notice this effect at all. It seemed that the VC was faster at locking down the image. This is only my opinion, you may find differently. However, after using Nikkor VR from its earliest versions to the best VR II available today, I've grown accustomed to how it works. The Tamron seems to acquire the subject faster, and locks down tighter.
In my opinion, this VC feature alone makes the lens worth the cost. I handheld this lens in conditions that would make a less competent lens shudder—literally.
Formal Portrait Work
I used the Tamron during the formal portrait session in a wedding where I was limited to only two flash units, an SB-800 and a SB-900, with an SU-800 controller and Nikon CLS. By necessity everything was mostly direct flash. In FIG 2A, I used one SB-900 with its stock diffuser dome pointing somewhat toward the ceiling, on a Nikon D300s, and was working to control contrast as best I could.
|FIG 2A - Bride in front of pastel painting|
Within the limitations of this direct-flash portrait, I think the D300s/SB-900/Tamron combination performed quite well. No forehead or cheek hotspots, only minor shadows, and all detail in whites maintained. The Tamron provided accurate tonal and distance information to my camera and flash, so that exposing the image was effortless.
|FIG 2B - Bride and bridesmaids|
In FIG 2B, an SB-900 was pointed directly at the group, while a SB-800 was bounced off the white ceiling. My D300s and SU-800 commander unit, along with the Tamron lens were controlling the exposure. The combo worked well.
I'm always afraid to use a new piece of equipment during a wedding, so I was quite wary. However, since this was a digital wedding, I could see any serious problems on the camera's monitor. I went ahead and used the lens. From the results seen in FIG 2A and 2B, you can tell that I don't regret it.
I shot over 100 formal group portraits, with up to 21 people in them, during this wedding. Not a single image was incorrectly focused or badly exposed. Great lens performance.
During the reception of the wedding, all main lights were turned off, and everyone was dancing to strung-up white Christmas tree lights. The Tamron was able to acquire focus even under that very low light setting, with the assistance of the SB-900’s infrared beam, of course. I tried shooting these dark images with my AF-S Nikkor 16-85mm, but could not seem to get good autofocus. I quickly switched to the Tamron, with its constant F/2.8 aperture, and that did the trick. However, the proof in the pudding is whether or not the full combination of camera, flash, and lens can provide accurate exposure under very difficult conditions.
|FIG 3 - Bride and groom dancing by candlelight|
FIG 3 shows an example of the type of image I was able to capture shooting basically in the dark. In the background of the image you can see the tiny lights that were used to provide a romantic atmosphere for the dancing. The bride and groom were dancing and spinning, while I was doing my best to capture them for posterity. The lens, once again, gave the camera and flash correct information for balanced exposure, with no blowout of whites or skin tones. The lens/camera/flash let the darks suffer, and kept the bride and groom exposed well. That’s awfully hard to do.
Of course, in an image with this level of darkness, you expect to see some shadows go fully black, but the important bits were exposed correctly, and the image’s histogram just touched the highlight side of the histogram window. Under these conditions, that’s quite admirable performance from the combination. The Tamron can be trusted to deliver.
Now, let’s look at some technical information for this fine lens.
Technical Information (for Model B005)
The Tamron® SP AF17-50mm F/2.8 XR Di-II VC LD Aspherical (IF) lens is designed for use on a Nikon having a DX imaging sensor. It does not provide a large enough image circle to cover the size of an FX sensor, so it won’t work on a D700 or D3s/x unless you are shooting in the DX mode. It’ll work fine on all DX models from the Nikon D40 to D300s. Here is an acronym list explaining what all the symbols applying to this lens mean:
Acronyms for Tamron® SP AF17-50mm F/2.8 XR Di-II VC LD Aspherical (IF) (Model B005)
SP = Super Performance. Tamron’s best lenses.
AF = Autofocus
XR = Extra Refractive Index. Allows smaller lens diameter due to stronger refraction in front elements.
Di-II = Digitally Integrated. Designed for DX sensors (APS-C or 24x16mm).
VC = Vibration Compensation. Reduces handheld vibrations in three planes.
LD = Low Dispersion. Lens contains one or more elements that achieve apochromatic performance.
IF = Internal Focusing. The length of the lens does not change during focus.
BIM = Built-in Motor. Will work on smaller Nikons with no in-body lens AF motor.
As mentioned in the acronym list, the newest version of this lens (model B005) has a built-in autofocus motor (BIM), so it will work on the smaller Nikon bodies like the D40, D60, D3000, or D5000.
I read a review at PopPhoto.com about this lens, and they were rating it as having comparable sharpness from F/2.8 to F/11. I had a hard time believing this until I shot the images in FIG 4. I cut these sample segments out from an area between the middle and edge of the images.
|FIG 4 - Testing for lens sharpness|
I can honestly state that the lens performs nearly as well wide open as at any aperture down to F/11. The reason I say nearly, is that I note some mild edge softness and slight light falloff in the corners at F/2.8. It's gone by F/4. That's to be expected in most all lenses.
The absolute best sharpness is found at F/8 to F/11, but is entirely usable across all apertures. If you look closely at FIG 4, you'll see a lessening in sharpness at F/16 as diffraction starts to take its toll. However, I would feel comfortable using this lens at any aperture. This is a sharp one, for sure!
To test for distortion I shot against a concrete brick wall at various apertures. I tried to walk closer or farther away to keep the blocks somewhat close to the same size, so that they're easier to compare.
|FIG 5 - Testing for lens distortion|
I note some barrel distortion at 17mm, but by 24mm it seems to be gone. Since the focal range on this lens is so short, it is easier to control for distortion. I really can't see any distortion between 24mm and 50mm.
What's the worst case scenario for a lens? To be pointed directly into the sun. I gave this lens the acid test by standing in the superstore parking lot and including the sun in the image (see FIG 6).
|FIG 6 - Testing for lens flare and contrast|
As expected you can see the teardrop shaped rainbow effect chromatic flare in the lower right corner. In fact, if you look closely the greenish flare extends all the way from the left bottom corner to the sun. However, I've seen few lenses that don't give you this effect, and it's even added in movies sometimes since we are all so used to seeing it. The nice thing about this lens is that it maintained high contrast in the rest of the image. There is no milky effect that lowers the contrast of the entire image. The only areas affected by the sun are the actual flare reflections. The rest of the image is still high contrast and sharp.
I would consider this good reflection control and shows that the lens has good quality coatings on its elements. Otherwise, an image with the sun in it would be very low contrast as the light bounces around between the elements.
I was impressed with this lens' minimal light falloff. I use a Nikkor 16-85mm and battle relatively worse light falloff. There is some light falloff at maximum aperture and shortest focal length (see FIG 7).
|FIG 7 - Testing for lens flare and contrast|
F/2.8 shows falloff in the corners, but it is mostly gone by F/4. The only time I could really detect light falloff was at 17mm and F/2.8 and F/4. At any other focal length besides 17mm I could not detect any significant light falloff. There was just a tiny bit at 24mm and F/2.8. What you see in FIG 7 is "worst case scenario" in my opinion. This lens does not have serious light falloff problems, and what it does have is easily corrected in software.
To test for Chromatic Aberration (CA) with the Nikon D300s is a little more difficult than with some cameras. The D300s automatically removes CA when creating a JPEG. So, I shot this backlit tree on the left in FIG 8 in RAW instead, and processed it through Nikon Capture NX2 with "Lateral Chromatic Aberration" correction turned off.
|FIG 8 - Testing for lens chromatic aberration (CA)|
The results were what I would call excellent. In FIG 8 you can see the red opaque area of the big image represented at 100% on the right. Even at 500% I could not detect significant amounts of CA. This is a worst case scenario, too. Backlit tree limbs will show CA when it is present, in my experience. Can you see any? I can't!
Sample Images from Tamron
Now let's look at three larger sample images. One of them I took in Knoxville Tennessee at the colorful front of a bankrupt Circuit City store. The other two were provided by Tamron, since I did not have the lens during a colorful season (December) and couldn't get any beauty-in-nature shots. The two nature shots were taken by Tamron technical representative Rob Moody personally. He was using his Nikon D700 in DX mode (5.5mp).
FIG 9 – Architectural Example – Nikon D300s, Tamron 17-50mm F/2.8 VC, 1/250s at F/9, ISO 100
© Darrell Young
FIG 10 – Loch Raven – Nikon D700, Tamron 17-50mm F/2.8 VC, 1/800s at F/5.6, ISO 500
© Rob Moody
FIG 11 – Reflection – Nikon D700, Tamron 17-50mm F/2.8 VC, 1/80s at F/6.3, ISO 200
© Rob Moody
The lens uses a normal non-ultrasonic autofocus motor, but the focus is fast and quiet. I had no AF seeking issues, even in an extremely dark environment.
The end of the lens does not rotate during autofocus, so you can use your polarizer without difficulty.
The maximum aperture is a constant F/2.8 all through the zoom range.
It has 14 groups with a total of 19 elements.
It's angle of view is 78°45' to 31°11' (APS-C equivalent)
It has 7 aperture blades for a nearly circular opening
The minimum aperture is F/32
The minimum focusing distant is 11.4 inches (0.29m)
The maximum macro magnification is 1:4.8
Its filter diameter is 72mm
The lens weighs 20.15 ounces (570g)
It is 3.13 inches (76.5mm) in diameter and 3.7 inches (94mm) long.
It comes with a 72mm flower-shaped lens hood
It has a 6-year limited warranty in the USA
Earlier versions of this lens have won EISA's Best Product Award, American Photo's Editor's Choice Award, and Professional Photographer's HOT ONE Winner award.
A Look at this Lens
Here are a few images of the lens from different angles. This is one good looking lens; don't you agree? It takes pictures even better than it looks!
|FIG 12 – Tamron 17-50mm F/2.8 VC various views|
I would feel confident using this lens in almost any situation. It feels strong and robust, with a design and warranty showing that it's made for many years of usage. While not up to the heavy standard of a metal Nikkor lens, it doesn't cost as much either. For a photographer needing a good solid high-performance lens on a tight budget, this lens performs extremely well.
I love the constant F/2.8 maximum aperture. This lets me use the lens to isolate my subjects with shallow depth of field when wide open, and have plenty of depth when stopped down. It's surprisingly sharp wide open. The specs I've read on other more technical reviews show very similar sharpness results from F/2.8 to F/11, and some minor sharpness loss due to defraction between F/16 and F/32. Quite an impressive lens! It's highly corrected and acceptable wide open, which is unusual in a lens of this price range.
I read a review of an earlier version of this lens on Popular Photography's website, and they claimed that it optically outperforms the Nikkor 17-55mm F/2.8 lens. I can tell you that the images I shot with it are very sharp and have excellent color contrast. It is a great normal lens for general use on a camera like the Nikon D5000, D90, or D300s.
With the Tamron 17-50mm F/2.8 VC, other photographers will wonder how you took such sharp images. Pro quality images at a reasonable lens price!
Keep on capturing time ...
Darrell Young, a.k.a.Digital Darrell
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