Tamron SP AF28-75mm F/2.8 XR Di LD Aspherical (IF) Macro
Cheap man's L lens without the L price. Used Tamron 24-70 VC easily cost RM3K nowadays.
The Tamron SP AF28-75/2.8 XR Di LD Aspherical (IF) Macro is a fast, general purpose lens for both digital and film cameras. On a film camera the 28-70mm range covers a lot of applications from landscapes and photojournalism to travel and environmental portraits. On a typical APS-C digital camera, such as the Canon EOS 20D or the Canon Rebel XT, it has the same field of view as a 45-120mm lens would on a full frame 35mm camera. This range also has a number of "typical applications" but perhaps of most interest is that it covers the "portrait" range, which traditionally has been from about 80mm to 105mm.
Of course you can take portraits with anything from a wideangle to a telephoto, but most portraiture is done with short telephotos (80-105mm). A fast (f2.8) lens also lends itself to portraiture, where a smaller DOF gives a more diffuse background.
The Tamron SP AF28-75/2.8 XR Di LD Aspherical (IF) Macro is a Tamron "Di" lens. Di lenses designed with digital SLRs in mind and Tamron say that they have higher resolution, better control of flare and ghosting, less light fall-off and lower chromatic aberration than earlier designs.
Note that the Tamron SP AF28-75/2.8 XR Di LD Aspherical (IF) Macro lens, although designated as digital ("Di") has full frame 35mm coverage. It can be used both on APS-C sensor DSLRs and on full frame digital or film cameras.
The lens solidly constructed with a low reflectivity black finish and a rubberized zoom control. It comes with a "petal" style detachable lenshood. The barrel material appears to be plastic.
The zoom can be locked in the 28mm position so that the lens doesn't extend when being carried in a downwards position.
Focus can be switched between AF and MF with a small switch on the left, near the lens mount. Manual focus is smooth and well damped with about a 51 degree rotation of the rubberized focus ring from 0.33m to infinity. There are no depth of field scales and no IR focus identification mark. It's marked with focal lengths of 28, 35, 50, 60 and 75mm
Focus speed is good. It takes the Tamron SP AF28-75/2.8 XR Di LD Aspherical (IF) Macro about 0.65 seconds to go from 0.33m to infinity (or infinity to 0.33m). Focusing isn't silent but it's pretty quiet and certainly not a problem.
The lens extends when zoomed (from around 92mm long at 28mm to around 129mm long at 75mm), but does not change length on focusing (it's internal focus - IF) and the front of the barrel does not rotate when the lens is zoomed or focused. However the focus ring does spin during autofocus, so keep your hands away from it.
The Tamron SP AF28-75/2.8 XR Di LD Aspherical (IF) Macro uses three types of special optical elements as shown above. XR glass (extra refraction) is glass of high refractive index, used to keep the lens short. LD (low dispersion) glass is used to control and minimize chromatic aberration. Aspherical elements are used to minimize aberrations like spherical aberration which become more troublesome in fast lenses.
The lens has a close focus distance of 0.33m which gives a maximum magnification of 1:3.9 at 75mm. Although the official name of the lens includes the term "macro", it's really more accurately described as "close focusing". True macro lenses usually give 1:2 or 1:1 magnification and are specially optically corrected to ensure low distortion, flat field and high sharpness at very close focus distances.
Technical assessment of performance
At 28mm center sharpness of the Tamron lens was good at all apertures. Sharpness peaked around f4 to 5.6 at which point edge shapness was only slightly lower than center sharpness. Wide open edge sharpness was down a little on center sharpness, as might be expected, but stopping down to f4 brought it up nicely.
The Tamron was somewhat better than the Canon 28-135 at all apertures down to about f11. At smaller apertures both lenses showed similar performance, with maybe a slight advantage to the Tamron in terms of edge sharpness. This is pretty much as expected since at apertures of f16 and smaller diffraction is generally the limiting factor on sharpness in the center of the frame and is the same for all lenses.
At 50mm the Tamron was actually very slightly sharper then the Canon 50/1.8 prime at equal aperture. The difference was small and in real world images might be hard to detect. Both lenses gave peak performance from about f4 to f8. At f11 and smaller apertures the effects of diffraction lowered sharpness.
The Canon 28-135 trailed in sharpness. It wasn't bad but it was a notch down on the Canon prime and Tamron 28-75.
Again the Tamron 28-75 was somewhat sharper than the Canon 28-135 at all apertures. Wide open at f2.8 there was some softness but at f4 things were sharp and performance from f4 to f8 remained pretty constant. Edge sharpness increased as the lens was stopped down and peaked around f8.
The Tamron SP AF28-75mm F/2.8 XR Di LD Aspherical (IF) Macro is a good lens. It's well built, small, fast, light, sharp, flare resistant and affordable.
It does sharpen up a tad when stopped down from f2.8 to f4, but I've never seen an f2.8 (or faster) lens that didn't get better when stopped down, so this really isn't a strike against it. It's a reflection of the difficulty of controlling aberrations in fast lenses.
Compared with the Canon 28-135/3.5-5.6 IS at the same f-stop, the Tamron is sharper and more resistant to flare, though of course the zoom range is less and it doesn't have IS. However the Tamron 28-75 does well with a 1.4x multiplier, so if you need a bit more reach you can get it thet way. Overall I have no hesitation in recommending the Tamron SP AF28-75/2.8 XR Di LD Aspherical (IF) Macro to anyone looking for a fast lens with this zoom range.
Price: Rm 850 each (1unit available) [Used unit is Retailing at Rm1k]
Location: Meet at Jalan Klang Lama - OUG Plaza (Yaohan) McDonalds or Pearl Point Hotel Starbucks 58200 Kuala Lumpur MY
Reason for sale: Trader
Delivery: 1. Always best to meet up and test until satisfy.
2. Can also post it to you, kindly call to discuss the alternatives.