The Tamron SP 17-50mm f2.8 XR Di II LD Aspherical is from Tamron’s high performance SP range, and with a fast f2.8 aperture throughout the zoom range this is aimed at those looking for image quality above all. The Tamron 17-50 f2.8 has already won an award as the “Best Product” in the consumer lens category of the EISA Awards 2006-2007.
I’ve been looking forward to trying this lens out - like everyone else who’s been taking pictures for a long time I still tend to think of a 28-70 as a standard zoom, where with most digital SLR cameras what we now need is this - a 17-50mm f2.8 - which with a Nikon or Pentax DSLR is equivalent to a 25.5-75mm or with a Canon its a 27-80. Incidentally - this is a digital only lens and can’t be used with 35mm film or with full frame sensors.
Tamron lenses are usually very well made and this one is no exception. It feels great in the hand and at 430g it’s not too heavy or big to use with some of the smaller DSLR bodies.
Technically this lens has all the new technology of aspherical elements, low dispersion glass and what Tamron calls XR glass in a 16 element design with internal focusing and a 67mm filter thread. All in all everything is there for a very special lens.
The first thing I noticed with the Tamron 17-50 f2.8 test frames was that even this good a lens isn’t immune to distortion at 17mm - to be honest, there’s more than I expected, with noticeable barrel distortion around the edges of the frame, but that’s about it with the bad news. Even at full aperture the Tamron 17-50 f2.8 resolves lots of fine detail and has an attractive softish tonal response which preserves information and gives you lots to work with. Many modern lenses use increased contrast to give high apparent sharpness - The Tamron 17-50 f2.8 doesn’t need that sort of help. Resolution throughout the range even at full aperture, is exceptionally good. There is a little softness at 17mm but you’re talking barely noticeable, and easily corrected. Used with the Canon EOS 20D there were no signs of vignetting or of CA and the corners, although a little softer than the center field, still had lots of detail. Moving up the zoom range, at 35mm overall resolution was good enough to have me checking the EXIF to see that they really were taken at f2.8 - they were so sharp. Continuing to 50mm and f2.8 brought a slight drop in sharpness in the center and more in the corners - Still very good for f2.8 though. By f5.6 results were excellent at all settings and right into the corners.
This is a very good lens, and one I would highly recommend - not perfect, with more distortion than I expected, but Photoshop, PT Lens or DxO will take care of that. Considering the price tag of the Tamron 17-50 f2.8 is less than half that of the Nikon or Canon equivalent it’s also good value. If you’re finding your kit lens just isn’t as good as your DSLR deserves, the Tamron SP 17-50 f2.8 XR Di II LD Aspherical [IF] could be just what you’re looking for.