(From Tamron lens literature) Tamron introduces a new version of the famous 90mm macro lens for film and digital photography. Tamron 90MM, often referred to as “the portrait macro”; and loved by photographers all over the world, is now reborn as a Di lens that is perfect for use with both film and digital cameras.
I have to admit that I really love macro lenses, and this Tamron 90mm f/2.8 seems like a real winner, particularly at its price point. Let’s take a closer look:
In the sharpness department, this lens presents offers no opportunity for complaint. It’s just a hair off critical sharpness wide open, but at f/4 it’s “prickly sharp”, and stays that way all the way out to f/11. Diffraction limiting starts to set in about f/16, and at f/32, diffraction makes for a very soft image. Across its broad sweet spot though, this lens is extremely sharp, and almost perfectly uniform across the entire frame.
The Tamron 90mm f/2.8 also does very well in terms of Chromatic Aberration, with low to moderate maximum CA and low average CA.
On a sub-frame camera, light uniformity is excellent across the board. Shading hits a maximum of only 0.2 EV wide open, and drops to more or less unmeasurable levels at f/4 and higher.
This focal length seems to be a nearly ideal one for lens designers to minimize distortion: The most distortion the Tamron 90mm f/2.8 shows just 0.04% pincushion, and average distortion is less than half that value.
The Tamron 90mm f/2.8 uses a conventional (as opposed to ultrasonic) motor, so isn’t quite as fast nor as quiet as lenses powered by the more advanced technology. It doesn’t do bad though, taking about 1.8 seconds to slew from closest focus to infinity, or a bit under a second when the focus-range switch on the side of the barrel is set to its “Limit” position (which limits the closest focusing distance to about 10-11 inches from the front of the lens). On our EOS-20D test body, focus acquisition and tracking seemed precise and sure-footed.
Build Quality and Handling The Tamron 90mm f/2.8 doesn’t rise to the “built like a tank” quality of some manufacturer’s primes, but its plastic barrel feels sturdy and solid, and manual focus operation is very smooth. The plastic construction does help a little with weight too, so this lens doesn’t unbalance the camera to the extent some lenses built with more metal might.
The aforementioned focus limit switch is helpful when you’re shooting at subject distances greater than a foot or so, as it greatly reduces the amount of time the camera could spend hunting for correct focus. At a range of ~11 inches from the front of the lens, and mounted on a 1.6x crop factor DSLR, the field of view is about 2.6 inches (67mm). With the focus limit disabled, the minimum field of view is about 0.87 inches (22mm), with a working distance of about 3.5 inches (~9 cm) from the front of the lens.
Speaking of working distance, for some reason, the front element of this lens is recessed into the barrel about 1.5 inches (~4cm). This decreases the working distance by that amount, but may also eliminate the need to use the included lens hood in all but the most extreme flare conditions. In common with other non-IF (Internal Focusing) lenses, the barrel of the Tamron 90mm f/2.8 extends quite a distance (about 2 inches, or 5 cm) as you focus closer.
This lens also has a different way of switching between manual and automatic focusing, which is accomplished by sliding the focus ring forward or back on the lens barrel. We found this much more convenient than the usual small slide switch most lenses use. As a visual cue that you’re in manual focus mode, a blue ring around the end of the lens barrel is revealed when the focus ring is slid back to the manual position.
Prime macro lenses in the ~100mm range tend to be pretty darn good, regardless of who builds them, so competition for the Tamron 90mm f/2.8 is pretty stiff. It holds its own pretty well though. As of this writing in mid-November, 2006, other lenses we’ve tested in this range include the Canon 100mm f/2.8 the Nikon 105mm f/2.8, and the Sigma 105 mm F2,8 EX Makro.
In terms of sharpness, the Tamron 90mm does very well, and may in fact be the sharpest of the group, from about f/4 through f/11. (The Sigma may be almost imperceptibly sharper at f/11 and f/16.) All four lenses show very low shading and distortion. In terms of CA, the Sigma wins out over the other three, and the Tamron is slightly worse than the two manufacturer primes.(Although the differences there are small enough that they may be inconsequential.) Price-wise, the Tamron and Sigma are almost a toss-up, both running about a hundred dollars below the price of the manufacturer’s lenses. (Except the new Nikkor 105mm f/2.8 VR lens, which is a bit over twice the cost of the Tamron, due in part to its inclusion of Vibration Reduction technology.)
At the end of the day, the Tamron 90mm f/2.8 macro stacks up very well against its competition. It’s tack sharp, with very low distortion and shading, and has chromatic aberration comparable to that of competing manufacturer’s lenses. Against its most direct competitor, the Sigma 105mm f/2.8, the Tamron is noticeably sharper at f/4, and slightly sharper from f/2.8 – f/8, but has slightly higher chromatic aberration. Bottom line, this is an excellent macro lens at a very attractive price, and available in a wide range of lens mounts (Canon, Minolta/Sony, Nikon, and Pentax).
Full-Frame Test Notes:
The full-frame test results for the Tamron 90mm f/2.8 macro lens look very similar to its sub-frame results, with the usual slight improvements from the larger pixels on our EOS-5D test body, and slight decreases in performance in the corners of the frame
Thanks to the 5D’s larger pixels, the Tamron 90mm f/2.8’s sweet spot extends from f/4 all the way to f/16, but there was some noticeable blurring in the upper corners of the frame wide open at f/2.8. Shading does increase to a bit over a half a stop at f/2.8 and a quarter stop at f/4, but drops to about 0.15 EV at f/5.6 and higher. Geometric distortion increases only a tiny amount, to 0.05% pincushion, while Chromatic Aberration drops just slightly relative to the sub-frame results on the 20D body.
The larger full-frame image circle presents a challenge to some lenses, but the Tamron 90mm f/2.8 takes it in stride quite easily, making this an excellent lens for full-frame macro work.