Model 28A
4.8x Macro Zoom
SP Symbol28~135mmF/4-4.5
High Performance 4.8x Macro Zoom
Tamron SP Adaptall-2 28-135mm F/4-4.5 Model 28A Lens

Tamron SP 28-135mm F/4.0-4.5 Model 28A: A wide angle to moderate telephoto zoom lens which offers above average optical performance. This lens features an extraordinarily complex mechanical design since all lens elements move as four separate groups at different rates when zooming. Tamron accomplished this mechanical engineering feat by using a system of nested sleeves controlled by a series of five cam-slots and cam-followers. A separate solid brass focusing helicoid moves the entire lens forward during the "macro" focusing action. This feature is engaged by pressing a small button on one of the two "macro" ring grips and then rotating the macro ring. Maximum macro magnification ratio is 1:4 at the 28mm zoom position.

Overall, this is an extremely versatile lens since it is sharp, has a decently fast maximum aperture and covers everything from wide angle to medium telephoto. Tamron rightly chose to optimize the optical performance of this lens for the wide angle to slight telephoto settings since these focal lengths are the most frequently used in everyday shooting situations. Optical performance is above average within the 28 to 80mm zoom range. Off-axis performance drops off to average between the 80 to 135mm settings. On-axis performance is very good throughout — even in macro mode. Macro performance is decent for the central 50% of the field of view but then rapidly falls off towards the corners. Keep in mind that the macro mode was built into this lens as an additional sales feature. Nevertheless the macro is quite usable in a pinch, especially if your macro subject is centered and occupies no more than about one half of the field of view.

Lens Specifications:

Lens Model 28A
Focal Length 28 — 135mm
Aperture Range f/4~4.5 — 32, AE
Angle of View 75°~18°
Optical Construction
(Groups / Elements)
10 / 17
Min. Focus from Film Plane
(normal mode)
78.7" (2.0m)
Min. Focus from Film Plane
(macro mode)
51.2" (1.3m) at f=135mm
10.2" (0.26m) at f=28mm
Macro Mag. Ratio 1:1:4 at f=28mm
Filter Size 67mm
Diameter 2.8" (70mm)
Length at
[w/Nikon mount]
4.2" (106mm)
[4.4" (110.5mm)]
Weight 25 oz. (710g)
Lens Hood Bayonet type #45FH (optional extra).
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