Tamron SP AF28-75mm f/2.8 XR Di LD Asp IF Macro

Gary Wolstenholme test the small and light Tamron 28-75 f/2.8 lens. With downsizing technology and internal focusing, this could be a sheep in wolf's clothing.

Tamron's 28-75mm costs around £357 and has a bright f/2.8 maximum aperture throughout the zoom range. It is amongst the cheapest lenses of the specification, which makes this lens excellent value for money. Sigma are the only other third party manufacturer offering lenses of similar specification. They have two f/2.8 zooms covering the 24-70mm range, one with a silent focusing motor, which costs £749, and one driven with a standard focusing motor which costs £433. Both lenses are much larger and heavier than the Tamron, but offer a useful extra bit of wide-angle coverage.

Manufacturers own offerings are designed as professional workhorses, so they have the build quality and price tag to match. Nikon's 24-70mm f/2.8 costs £1194 but is a weather-sealed lens with silent focusing. Canon's 24-70mm f/2.8L is one of their L series lenses, which costs £1020. Sony's 24-70mm sports optics by Carl Zeiss, sports silent focusing and costs £1296.

Tamron SP AF28-75mm f/2.8 XR Di LD Asp IF Macro: Features and handling
When this lens is mounted on a camera, you would be forgiven for mistaking it for an f/3.5-4.5 kit zoom. Tamron's XR technology has shrunk this lens down to a minuscule size, especially when compared to Nikon, Canon and Sony's behemoths. This means the lens balances well on smaller camera bodies, as well as on larger professional bodies and makes the lens an ideal travel companion, especially when teamed up with a full-frame body with good high ISO performance, such as the Nikon D700 or canon 5D MkII.

An internal focusing design has been employed on this lens, so it does not expand during focusing. Use of filters is aided by the fact that the front element does not rotate. The lens barrel is dominated by the large rubberised zoom ring, which has a very smooth action. The sample I tested did not suffer with zoom creep, although a locking mechanism is included so the lens does not extend during transport.

During auto-focus, the focus ring on the lens does rotate and there is no way to disengage it, so care needs to be taken to avoid it catching your fingers as it whizzes back and forth. Although the lens doesn't have a silent focus motor, the auto-focus action is swift and accurate enough to make full use of the bright maximum aperture.

Overall, I have to say I really enjoyed using this lens. Due to it's lightweight, I barely noticed I had a wide aperture zoom on my camera during testing. The light weight makes the lens perfect for travelling and the small size makes the lens less conspicuous when using it out and about.

Tamron SP AF28-75mm f/2.8 XR Di LD Asp IF Macro: Performance

For this review, the lens was tested on a 12Mp Nikon D700 using Imatest.

At 28mm, this lens is an outstanding performer, producing pin-sharp images right from the maximum aperture. The best overall image quality is obtained at f/8, where the sharpness towards the edges of the frame catches up with the already excellent centre resolution. As is typical of this kind of lens it starts to become a little softer as it is zoomed in.


By 50mm, the centre resolution is excellent, but the edges of the frame lag behind somewhat. Stopping down to f/11 will give very good sharpness across the frame. At 75mm, the resolution has dropped off a little more, but is still acceptable in the centre at f/2.8 and very good stopped down to f/4. f/11 produces images with very good sharpness from corner to corner.

This resolution characteristic at longer focal lengths lends itself to applications where your subject will usually be in or near the centre of the frame, such as portraiture. For it's price, this lens performs very well indeed.

Resolution at 28mm

Resolution at 50mm

Resolution at 75mm

Chromatic Aberrations are well controlled by this lens. At their worst, they cover just over half a pixel width at 28mm and f/2.8, which will be barely noticeable in normal shooting scenarios. As the lens is zoomed in, any signs of colour aberration virtually disappear.

Chromatic aberration at 28mm

Chromatic aberration at 50mm

Chromatic aberration at 75mm

As is typical for most wide aperture zooms, the Tamron 28-75mm suffers with light fall-off in the corners at f/2.8. At 28mm the corners are 2.4stops darker than the image centre, which will be quite noticeable in many circumstances, this effect is virtually gone when the lens is stopped down to f/5.6 or smaller. At 75mm, vignetting is much improved, with the corners of the image area being only 1.3 stops darker than the image centre. Stopping down to f/4 virtually eliminates this effect.

Distortion is quite strong at 28mm, with Imatest recording 4% barrel distortion. The pattern is uniform, so this could easily be corrected in image editing software if straight lines are important. As the lens is zoomed in, the curved lines disappear, the lens only producing 0.7% pincushion distortion at 75mm.

Ghosting and flare are very well controlled by this lens. Strong point sources of light will create a little flare, but certainly not much. Contrast is well preserved in these instances also. Light sources just outside the frame will cause a small loss of contrast, but this can be virtually eliminated by using the supplied petal-shaped hood, which does a sterling job of shielding the front element from extraneous light.

Tamron SP AF28-75mm f/2.8 XR Di LD Asp IF Macro: Verdict
Even without taking the price into consideration, this lens is an impressive performer producing images with very good to excellent resolution throughout the range.

The small size and light weight of this optic will also appeal to many, who would like the flexibility of an f/2.8 zoom, without the size, weight and price tag usually associated with such a lens.

FEATURES
HANDLING
PERFORMANCE
VALUE
OVERALL

Tamron SP AF28-75mm f/2.8 XR Di LD Asp IF Macro: Specification

Price:	£357
Contact:	www.tamron.co.uk
Filter size:	67mm
Format:	Full frame/FX
Construction:	16 elements in 14 groups
Angle-of-view:	75-32°
35mm equivalent focal length (on APS-C body):	42-115mm
Internal focusing:	Yes
Image stabilisation:	No
Minimum focus:	33cm
Maximum aperture:	f/2.8
Minimum aperture:	f/32
Weight:	510g
Size:	92x73mm
In the box:	Petal shaped lens hood

The Tamron SP AF28-75mm f/2.8 XR Di LD Asp IF Macro costs £356.99 and is available from Warehouse Express here:

Tamron SP AF28-75mm f/2.8 XR Di LD Asp IF Macro

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