Digital Imaging Global Site


135mm F2.8 [T4.5] STF


  • Portrait

  • Lens groups/elements: 6/8 (includes one APD group with two elements)
  • Minimum focus: 0.87 m
  • Filter diameter: 72 mm
  • Size: 80 mm (diameter) x 99 mm (length)
  • Weight: approx. 730 g

This special-purpose lens allows you to create truly unique images with exceptionally smooth transitions between in-focus and defocused areas. This is achieved through apodization optics, which gives your images added dimensionality and also contributes to the natural spread of highlights. Clarity at the point of focus is superb, and vignetting and double-line defocusing are avoided. A manual aperture ring and circular aperture give you added control over defocusing, which is especially desirable around T4.5 to T6.7.

STF (Smooth Trans Focus) Lens

Ideal defocusing with the STF lens

In a conventional lens, the amount of light collected at the periphery of the lens is roughly equal to the amount of light at the center. This results in uniformly sharp dots at points “b” and “c,” below. The STF lens, however, uses a special filter called an “apodization optical element” that collects less light at the lens periphery, which results in diffusion at the edges of the dots instead. Smoother defocusing is obtained due to this optical characteristic.

STF lens & T numbers

Because the STF lens collects less light overall than conventional lenses, F-stops are replaced by T (transmission) numbers. In practice, the two types of values can be used interchangeably to determine exposure.

Main specifications

Lens configuration (group / element) 6 / 8 (incl. APD element 1/2)
35mm-equivalent focal length (APS-C)* (mm) 202.5
Angle of view (APS-C)* 12°
Angle of view (35mm full frame) 18°
No. of aperture blade 9 (auto), 10 (manual)
Min. aperture (F) 31 [T32]
Max. magnification ratio (x) 0.25
Min. focus (m) 0.87
Distance Encoder for ADI flash metering -
Filter dia. (mm) 72
Hood shape / mount round / bayonet
Dimensions: Dia. x L (mm) 80 x 99
Dimensions: Dia. x L (in.) 3-1/8 x 3-7/8
Weight: (approx.) (g) 730
Weight: (approx.) (oz.) 25.8
Provided accessories hood (ALC-SH0014), case

Specifications are based on the latest information available at the time of announcement and are subject to change without notice

* With interchangeable-lens digital cameras incorporating APS-C type image sensors.
When mounted on α series cameras with APS-C type sensors, the actual angle of view will be equal to the angle obtained at a focal length approx. 1.5 times longer than stated.
Less light is transmitted by any lens at the image periphery. If the light falloff becomes excessive, reduce the aperture by 1 or 2 stops.


A-mount 35mm full frame

A-mount APS-C

E-mount 35mm full frame & Mount Adaptor

E-mount APS-C & Mount Adaptor

α Lens accessories

Rear Lens Cap


Front Lens Cap


MC Protector


Circular PL Filter


ND Filter