The Tamron 28-75mm f/2.8 XR Di Lens is a relatively small normal zoom lens that delivers good image quality and a wide fixed f/2.8 aperture for a low cost.
Pictured above from left to right are the Sigma 28-70mm f/2.8 EX DG Lens, Tamron SP 28-75mm F/2.8 XR Di Lens, Canon EF 28-135mm f/3.5-5.6 IS USM Lens and Canon EF 24-70mm f/2.8 L USM Lens.
The 28-75's full product name is "Tamron SP AF28-75mm F/2.8 XR Di LD Aspherical [IF] Lens" and requires an abbreviation key for many of us ...
SP - Super Performance [Tamron's highest quality lens line] AF - Autofocus XR - Extra Refractive Glass [reduces lens size] Di - Digitally Integrated Design [to reduce ghosting, flare, CA and peripheral light fall-off along with improved resolution] LD - Low-Dispersion lens elements [to reduce chromatic aberration for sharper images] Aspherical - contains aspherical elements [compensates for spherical aberration and distortion, making for better performance with fewer elements [and thus allowing for smaller, lighter lenses] [IF] - Internal Focusing
Seems to me that a few of these specifications could have been removed from the product name. :]
One of the most notable feature of this lens is the good center sharpness it delivers, with decent center sharpness at f/2.8 and good center sharpness at f/4. I make the center designation clear as corner sharpness is a completely different story. The Tamron 28-75mm f/2.8 XR Di Lens is very soft in the corners. My first copy was dreadfully soft in the upper left portion of the frame. My second copy has very poor right side performance - especially at 35mm. Corner sharpness improves as the lens is stopped down and zoomed out [toward 75mm]. But, some corner softness is still present at 75mm and f/8. Fortunately, users of 1.5x/1.6x FOVCF digital SLR camera bodies will avoid the worst of this pain. Note regarding the ISO 12233 test chart sample crops: I was told that I had a bad copy, so I retested the first copy and then bought and tested [a very time-consuming process] a second lens. The results from the second lens were worse than the first. I may go for a third lens at some point, but need to move on to other tasks. There may be better copies of this lens available, but quality control is definitely a concern.
In center sharpness, the Tamron 28-75mm f/2.8 XR Di Lens is similar to the much heavier, larger and more expensive Canon 24-70mm f/2.8 L USM Lens. These two lenses swapped wins at various focal lengths - Canon won 35mm and 70mm, Tamron won 28mm and 50mm, and of course Canon won 24mm and Tamron won 75mm. The Canon 28-135 IS USM Lens was generally softer than the Tamron in the center.
Moving the comparison out to the image edges changes everything. At the edges, the Canon 24-70mm L is far superior in sharpness to the Tamron 28-75 at all focal lengths and all apertures. At the edges, the Canon 28-135mm IS is slightly sharper than the Tamron 28-75 at most focal lengths and apertures. And nearly all lenses are sharper than this Tamron's top left corner. Again, users of 1.5x/1.6x FOVCF digital SLR camera bodies will avoid most of this pain. I seem to get sharper corners in real life shots leading me to believe the plane of sharp focus is not exactly a plane. I didn't conduct technical tests to prove this point.
Distortion in the Tamron 28-75 is typical [not worse, not better] for a decent quality normal zoom lens - barrel distortion on the wide end to 35mm or so and pincushion distortion on the long end.
CA [Chromatic Aberration] is well controlled with only slight CA visible at the wide end in harsh situations. Flare is also well controlled. The Tamron 28-75 has good contrast - better than 28-135 IS but not as good as the 24-70 L. The 28-75's yellow/warm cast is not my preference.
Light fall-off is very well controlled with exception of strong full frame corner darkening with a wide open aperture - especially at 24mm with some at 70mm. TheTamron 28-75 is better than the 24-70 L and much better than the 28-135 IS in this regard.
Seven aperture blades are good, but bokeh appears slightly harsh in some of my evaluation shots. The Tamron 28-75 tends to overexpose most shots slightly with no compensation dialed in.
The Tamron 28-75mm f/2.8 XR Di Lens' AF is noisy and somewhat slow. More concerning is the 28-75's difficulty in locking focus in low light/low contrast situations. My Canon 17-40mm f/4 L USM Lens quickly focus-locked in situations where the Tamron only hunted. FTM [Full Time Manual] focusing is not on the 28-75's feature list. Since the focus ring turns during AF [definitely not my favorite feature], focus distances can be [and are] marked on the focus ring itself instead of in a window. The Tamron manual indicates that damage can be done to the lens if the focus ring is held while the lens is autofocusing. I frequently found myself supporting the lens [at least partly] by the focus ring in real use. Of great importance - AF accuracy has been very good. The Tamron 28-75 is an internal-focusing lens. The objective lens does not rotate with focusing or zooming and does not extend with focusing.
The Tamron 28-75 sports a decent, solid feeling build quality. The zoom and focus rings are nicely sized and well damped. The rings are not as grippy/sticky as I prefer, but the deeply patterned rubber is not hard to grip. Both rings have a short rotation distance - adjustments tend to be rapid [as opposed to fine]. Since I am most often using Canon lenses, I personally find the reverse-direction-rotating zoom ring to be awkward. I zoom in when I want to zoom out.
Like most normal focal length range zoom lenses, the Tamron 28-75 extends with zooming. A lock switch is included to hold the lens at the 28mm retracted length. Unless this lens' zoom ring loosens a great deal over time, it is not needed.
Pictured above from left to right are the Sigma 28-70mm f/2.8 EX DG Lens, Tamron SP 28-75mm F/2.8 XR Di Lens, Canon EF 28-135mm f/3.5-5.6 IS USM Lens and Canon EF 24-70mm f/2.8 L USM Lens - all shown at their maximum extension.
This lens' focal length range is obviously 28mm to 75mm. This covers the basic focal lengths desired in a normal general purpose zoom lens but might feel long to some 1.6x FOVCF users. For me, a 24mm wide angle would be better [common on many other zooms in this class], but 75mm on the long end is a little nicer than the common 70mm max focal length.
A fixed f/2.8 aperture is as good as it gets in a zoom lens. The Tamron 28-75mm f/2.8 XR Di Lens will allow handholding and action-stopping until the light gets low. The f/32 minimum aperture will be useful to few as diffraction causes image softness to become unacceptable somewhere beyond f/16.
With a minimum focus distance of 13" [33 cm], the Tamron 28-75 is capable of about .26x magnification - not bad.
Pictured above from left to right are the Sigma 28-70mm f/2.8 EX DG Lens, Tamron SP 28-75mm F/2.8 XR Di Lens and Canon EF 24-70mm f/2.8 L USM Lens with lens hoods in place. Note that the 24-70 L hood does not extend while both the Sigma and Tamron hoods extend with the lens
While not diminutive, the Tamron 28-75mm f/2.8 XR Di Lens is relatively small for its quality. Measuring 3.6" [92mm] long and 2.9" [73mm] in diameter, the 28-75 weighs 1.50 lb [510 g]. Even the included cheap-feeling-but-quite-functional petal-shaped lens hood is small [3.5"/124mm wide and 1.75"/62mm long] and light. It is easy to install and locks into place. The inside of the hood is ribbed - not covered with a fuzzy material as Canon's hoods are. The filter diameter is a somewhat uncommon 67mm - at least you can share your filters with the Canon 70-200mm f/4 L USM Lens. No lens case or pouch is included, but the Tamron fits nicely in a Lowepro Lens Case 1W
I really like the Tamron front lens cap. It allows the outside or inside portion of the cap to be squeezed for removal. The inside release allows easy installation/removal with the lens hood in place. Although it is a petty issue, I don't like the Tamron rear lens cap. It fits loosely and only installs in a single position [Canon caps fit snugly in three positions]. However, it would not be hard to purchase a Canon brand replacement for this part.
A non-camera body manufacturer brand, the Tamron 28-75mm f/2.8 XR Di Lens is available in Canon [reviewed], Minolta, Nikon and Pentax mounts. You should know that there are some potential issues with third party lenses. Since Tamron reverse engineers [vs. licenses] manufacturer AF routines, there is always the possibility that a new body might not support an older third party lens. There have been examples of this happening in the past. Sometimes a lens can be rechipped to be made compatible, sometimes not. Second, there is the risk of a problem that results in the lens and body manufacturers pointing blame at each other. However, Tamron USA's 6-year warranty is far superior to Canon's standard 1 year warranty.
No lens is perfect, but the Tamron 28-75mm f/2.8 XR Di Lens delivers a lot for its price. The Tamron 28-75 would be a good general purpose zoom lens choice for 1.5x/1.6x FOVCF Digital SLR body owners unable to afford [or don't want the size/weight of] the Canon 24-70mm f/2.8 L USM Lens.
Bringing you this site is my full-time job [typically 60-80 hours per week]. Thus, I depend solely on the commissions received from you using the links on this site to make any purchase. I am grateful for your support! - Bryan