Sony AF 16 mm f/ 2.8 Fisheye Lens Manual

4-31

SAL16105 (DT 3.5-5.6/16-105) (DT 16-105mm F3.5-5.6)

This section describes the check/adjustment of focus-shift amount resulting change of focal-length by aperture setting.

• 1000 mm Collimator

• Flange Back Tester

• A-mount Attachment

• Flange Back Gauge (43.50mm)

• Aberration measuring cap 62mm (SAL16105)

1)

Perform “1. Preparations” of “4-3. OPTICAL AXIS CHECK/ADJUSTMENT”.

2)

Set the checking lens focus to the infinite.

3)

Set the focal length 105mm.

1)

Set the lens aperture to the open aperture position, and measure the flange back (f’F).

2)

Set the aberration measuring cap 62mm (F8 equivalent) on the tip of lens as shown in the Fig.4-7-1, then measure the flange back

(f’F).

3)

Calculate amount of focus-shift using the following formula, and check that the specification is satisfied.

The focus-shift amount of the checking lens is difference between the flange back (f’F) of open aperture and flange back

(f’F) reading (using aberration measuring cap 62mm).

Focus-shift = Flange back (f’F) reading (using aberration measuring cap 62mm) - flange back (f’F) of open aperture reading

Focus-shift (mm) = – 0.05 to +0.10

4)

Perform the “WRITE dSB”(Refer to Section 4-12).

Aberration measuring cap 62mm (SAL16105)