Aperture

Stepless aperture range

 

This lens has two aperture settings; A position and a stepless aperture control. Use the aperture ring to switch between the two settings. T No. is used in both notation and control on the camera and lens.

To use the stepless aperture setting

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This setting allows stepless control of the aperture between T/4.5 - T/6.7. Turn the

 

 

 

 

 

 

 

 

aperture ring to set the desired aperture.

 

 

 

 

 

 

 

 

• This stepless range is recommended when a large aperture is desired.

 

 

 

 

 

 

 

 

 

A position

• Set your camera to A mode or M mode when using this setting. (In P mode or scene-

 

 

 

 

 

 

 

 

 

selection setting, the settings will be the same as A mode. In S mode, the settings will

 

 

 

 

 

 

 

 

be the same as M mode.)

 

 

 

 

 

 

 

 

• A slight click can be felt at the T/4.5, T/5.6, and T/6.7 marks.

 

 

 

 

 

 

 

 

• The index marks between T/4.5 and T/5.6 represent 1/3 aperture values.

 

 

 

 

 

 

 

 

• Stop-down metering is used when the stepless aperture is selected.

 

 

 

 

 

 

 

 

• When shooting, the aperture values set by the aperture ring are used. Those values are

 

 

 

 

 

 

 

 

not accurately reflected in the values displayed or recorded by the camera.

 

 

 

 

 

 

 

 

To use the A position

This setting (A position) allows the lens to be used the same way as traditional manual-focus lenses. Set the aperture on your camera.

• All exposure modes (P, A, S, M) can be used on the camera.

Aperture Information

This lens has two apertures; the stepless aperture, manually controlled with
Stepless aperture
the aperture ring, and the automatic aperture (A position), controlled by

 

the camera. In the stepless aperture setting, emphasis is put on the aperture

 

shape, which is rounder than the automatic aperture. For large aperture

 

settings, selecting the stepless aperture is recommended.

 

Automatic aperture (functioning when set to the A position)

Depth of field (in meters)

When focus is set on a subject, anything at that same distance will appear sharp, and anything within a certain range before and beyond the subject will also appear in focus; this is called depth of field. Depth of field depends on the subject distance and aperture you choose.

 

T/4.5

T/5.6

T/6.7

T/8

T/11

T/16

T/22

T/32

∞

∞

∞

∞

∞

∞

∞

∞

∞

114.8

97.8

82.3

69.2

49.0

34.7

24.6

17.4

 

10m

10.91

11.08

11.32

11.61

12.44

13.84

16.48

22.58

9.23

9.11

8.96

8.79

8.37

7.84

7.20

6.46

 

5m

5.21

5.24

5.29

5.35

5.51

5.76

6.15

6.80

4.81

4.78

4.74

4.69

4.58

4.42

4.22

3.97

 

3m

3.068

3.080

3.096

3.115

3.165

3.239

3.350

3.522

2.935

2.924

2.910

2.894

2.852

2.795

2.719

2.618

 

2m

2.027

2.032

2.038

2.046

2.065

2.094

2.135

2.198

1.974

1.969

1.963

1.956

1.939

1.915

1.882

1.837

 

1.5m

1.514

1.156

1.519

1.523

1.533

1.547

1.567

1.597

1.478

1.484

1.481

1.478

1.469

1.456

1.439

1.415

 

1.2m

1.028

1.209

1.211

1.213

1.219

1.226

1.238

1.254

1.192

1.191

1.189

1.187

1.182

1.175

1.165

1.151

 

1.0m

1.005

1.006

1.007

1.008

1.011

1.016

1.023

1.033

0.995

0.994

0.993

0.992

0.989

0.985

0.978

0.970

 

0.87m

0.873

0.874

0.874

0.875

0.877

0.881

0.885

0.891

0.867

0.866

0.866

0.865

0.863

0.860

0.856

0.850

 

The depth-of-field scale and depth-of-field table are for 35mm-format cameras. The depth of field is shallower when you use Digital Single Lens Reflex Cameras equipped with an APS-C sized image sensor.

Exposure compensation

As the magnification increases, the amount of light reaching the image sensor decreases. This is automatically compensated in all autoexposure modes, or in the manual exposure mode as long as the exposure is adjusted according to the camera’s meter index. If your camera is set to the manual exposure mode and you are using a hand-held exposure meter, or if your camera is set to the manual exposure mode and you are using the Manual Flash Control function available on some external flash units, adjust exposure accordingly.

(E.g., when adjusting by the aperture, +1 means opening the aperture 1 more stop.)

Exposure correction

+1

+ /4

+ /2

+ /4

0

 

 

 

 

 

 

3

 

 

1

 

 

1

 

 

 

 

Magnification ratios

0.25X

0.20X

0.15X

0.08X

0.029X

 

Distance

0.87

1.0

1.2

2.0

5.0

 

 

 

 

 

 

 

 

m

 

 

 

 

 

 

 

About Apodization

A special “apodization element” is situated near the aperture of the lens optical system. This special optical element is a type of ND filter which gradually becomes thicker (darker) towards the perimeter, thereby reducing the amount of light that passes through around the outer perimeter. The aperture of this lens is indicated and controlled by the T No., which compensates for the reduction imposed by the special apodization element. The T No. can be used as the F No. on a normal lens when the exposure is determined.

 

Apodization element
Principle of defocusing effect improvement

 

 

Defocusing of a dot
Defocusing of a line

 

 

 

 

 

 

This lens
Intensity decreases gradually
Gradually diffused without losing
toward the perimeter
shape
Theoretical ideal traditional lens
Intensity stays the same
Line becomes thicker

Defocused images appear as blurred clusters of dots. A lens with well compensated aberration reproduces the image shape accurately, but cannot produce smooth blurs in a defocused area. There may be unpleasant blurs, which for example, make one line appear to be doubled, depending on the way of compensation. This lens adopts a special apodization element that provides a gradually diffused image toward the perimeter without losing the core shape. In other words, it provides soft and natural defocusing without transforming the original shape unnaturally.

Specifications

 

 

Equivalent

 

Lens

 

 

Minimum

Maximum

 

Filter

Dimensions

 

 

 

Name

35mm-format

 

Angle of

Angle of

Minimum

(maximum

Mass

 

 

 

groups-

focus*4

magnification

diameter

 

 

(Model name)

focal length*1

 

elements

view 1*3

view 2*3

(m (feet))

(×)

f-stop

(mm)

diameter × height)

(g (oz.))

 

 

 

(mm)

 

 

 

 

(mm (in.))

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

135mm

 

 

 

 

 

 

 

f/31

 

Approx. 80×99

Approx. 730

 

F2.8 [T4.5] STF

202.5

 

6-8*2

18°

12°

0.87 (2.85)

0.25

72

 

 

(T/32)

(3 1/8×3 7/8)

(25 3/4)

 

 

(SAL135F28)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

*1

The value for equivalent 35mm-format focal length is based on Digital Single Lens Reflex Cameras equipped with an APS-C sized image sensor.

 

 

*2

Including apodization element (1-2)

 

 

 

 

 

 

 

 

 

 

*3

The value of angle of view 1 is based on 35mm-format cameras, and that of angle of view 2 is based on Digital Single Lens Reflex Cameras equipped with an APS-C sized image sensor.

*4

Minimum focus is the shortest distance from the image sensor to the subject.

 

 

 

 

 

 

Included items: Lens (1), Front lens cap (1), Rear lens cap (1), Lens hood (1), Exclusive case (1), Set of printed documentation

Designs and specifications are subject to change without notice.
is a trademark of Sony Corporation.