This article was written by well-known journalist Jon Sienkiewicz. You can read more from Jon on his blog on Shutterbug magazine's homepage by clicking here.

A Lens So Sharp You'll Need to Wear Gloves

Images and Text by Jon Sienkiewicz

Tamron SP AF70-300mm Di VC USD

Tamron's 60th Anniversary 70-300mm zoom is sharp. It's so sharp that I carry it in a case so that I don't cut myself. The full name is Tamron SP AF70-300mm F4-5.6 Di VC USD XLD IF (Model A005). I had a chance to use one at the Bronx Zoo and around my neighborhood in early September. Of course, there's no real danger of injury, but it is one very sharp lens.

Explaining the sharpness of a lens is very much like trying to explain the clarity of a diamond, or the texture of an oil painting. Words alone cannot do an adequate job. One can take an objective approach and refer to MTF (Modulation Transfer Function) curves that scientifically quantify sharpness. That's okay, but it's a somewhat like saying that a certain brand of ice cream is sweet because it contains 44 grams of sugar per serving-you can't taste the numbers.

Another approach is to show you the results. That way you don't have to take my word for it-you can see for yourself. The best way, of course, would be for you to try the lens yourself.

To make the image above I made a copy of the original, unedited shot of the eagle and increased the size of the copy 400% in Photoshop CS4. I then used the Cloning tool to paste a circle containing the eye from the copy back onto the original. So in essence, what you're seeing side-by-side is the eye in its original size and enlarged 4X. The image has been resized so that it can be viewed conveniently on your computer, but you can still fully appreciate the sharpness and rich detail.

If you're into technical specs, this image was shot with a Nikon D300s at f6.3, 1/200th of a second, handheld at the equivalent of 450mm. Under normal circumstances, I cannot handhold a 450mm lens at 1/200 second. But the Tamron 70-300mm has VC, Vibration Control, which eliminates camera shake. Without VC, I would have had to shoot at 1/500 sec or higher, otherwise the slight, unavoidable camera movement (that's further magnified by the telephoto optic) would have obscured the sharpness of the details in this photo. In other words, I would have never been able to get this shot with a traditional lens.

Here's a similar example using the same enlarge-and-paste technique. This time I enlarged it a whopping 500%. I can count the lemur's eyelashes.

Another way to demonstrate sharpness is to take the opposite approach. In the image below I first cropped and enlarged the details I wanted to show, and then I pasted a reduced-size image of the full frame so that you can see what a tiny portion of the image I enlarged. As you can see, the bird's head is a small dot in the full frame, and the eye is barely a speck.

Throughout their 60 years of lens making, Tamron has been continually recognized as a technological innovator. In the 70-300mm zoom they used an advanced optical design that features an LD (Low Dispersion) and an XLD (Extra Low Dispersion) lens element made from specialized materials that prevent chromatic aberration. As a result, the SP AF70-300mm Di VC USD boasts sharper contrast, higher acutance and greater color fidelity than all others in its class.

The real-world benefit of the low and extra-low dispersion elements is truer colors without optical distortion and without the "dreaded purple fringe" chromatic aberration. The shot of the rose (above) is as brilliant and vibrant as the flower itself. You'll also notice that the background is entirely obscured. The long 450mm focal length allowed me to strictly limit depth-of-field so that the main subject literally jumps off the page. The bokeh (blur quality, or how the out-of-focus background is rendered) is superb.

This is a very versatile lens. The 60th Anniversary Tamron 70-300 zoom is not billed as a macro lens; nonetheless, I captured some excellent close-up effects, including this butterfly (above). This shot underscores the value of Vibration Compensation and another important feature: focusing speed. This is the first Tamron lens to use a USD (Ultrasonic Silent Drive), Tamron's patented ultrasonic autofocus drive mechanism. This USD mechanism delivers lightning-fast focusing, making it ideal for shooting sports, birds, kids or other fast-moving subjects-like butterflies.

It's also a solid choice for portraiture. The 70-300mm zoom range translates to 105-450mm as the film camera equivalent. At 105mm you can fill the frame with the subject and get pleasant perspective and compression.

The versatility extends to street photography and fireworks. Fireworks? With a telephoto zoom in September? Yes, fireworks. Our local fire department hosts a lavish fireworks exhibit over Labor Day weekend every year. This year I was able to fully fill the frame with aerial pyrotechnics by using the Tamron 70-300mm telephoto zoom. But don't take my word for it:

I like the way the Tamron 70-300mm handles. It's less than six inches long but it has a very secure grip that fills the hand. The zoom is smooth and authoritative-no jiggle or zoom creep. The Build Quality is what we've come to expect from Tamron: Outstanding. It sports a steel lens mount and feels firm and rugged. Cosmetically it's quite handsome. And it comes with a very functional lens shade. It's been awhile since anyone stopped me on the street and asked me about the lens on my camera, but this happened to me twice during the field test-once in Glen Rock, NJ and once at the Bronx Zoo. I'm blaming it on the lens shade-it looks very professional and impressive.

Summary

I expected this lens to cost in the $700 range, considering its overall performance, handling speed, high-tech construction materials like LD (Low Dispersion) and XLD (Extra Low Dispersion) glass elements and Ultrasonic Silent Drive. It covers a full 35mm-size sensor, too, not just APS-C. After using it for several days and witnessing its potent sharpness, I'd be willing to pay even more than $700 for it. So you can imagine how dumbstruck I was when I learned that it sells for much less than $500.

The Tamron SP AF70-300mm Di VC USD (Model A005) is truly "best in class" where sharpness is concerned, and that's reason enough to own one. The Vibration Control and other features are frosting on the cake.

Please check out my blog on Shutterbug magazine's homepage. Comment if you like what you read.

More About The Tamron SP AF70-300mm Di VC USD

• Voted Best Zoom Lens 2010-2011
• Unparalleled optical performance in a fast and steady telephoto zoom

In the pursuit to achieve the most outstanding image resolution in the 70-300mm class, Tamron's 60th Anniversary lens - the SP 70-300mm F4-5.6 Di VC USD (Model A005) - utilizes an advanced optical design that features an LD (Low Dispersion) and an XLD (Extra Low Dispersion) lens element made from specialized materials that prevent chromatic aberration. As a result, the SP 70-300mm Di VC USD boasts sharper contrast and greater descriptive performance than all others in its class. This is the first Tamron lens to sport USD (Ultrasonic Silent Drive), Tamron's very own ultrasonic auto-focus drive mechanism. This USD mechanism delivers fast focusing, making it a perfect telephoto zoom choice for photographing sports, racing, or other fast-moving subjects. The lens also boasts Tamron's proprietary VC (Vibration Compensation) image stabilization to assist in hand-held photography, not only at long focal length ranges where blurring is common, but also under low-lit conditions, dramatically enhancing photographic freedom. This combination of best in class image resolution, Ultrasonic Silent Drive and Vibration Compensation is a new achievement of Tamron technology, culminating in the production of a premium 70-300mm telephoto zoom lens. Winner of EISA Best Zoom Lens 2010-2011. Available for full-frame and APS-C sensor cameras in Canon, Nikon and Sony mounts (the latter without VC).

Tamron 6-Year USA warranty and $50 rebate thru 12/31/10 when purchased from RitzCamera.com