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4-4

SAL18135 (3.5-5.6/18-135 SAM) (DT18-135mm F3.5-5.6 SAM)

4)  Click the Calculate button to measure the image.
5)  After measuring, check the  G  values.
 Average 

G  value of the three images shoot with master lens: 

(a)

 Average 

G  value of the three images shoot with checking lens:  (b)

 

Calculate button

Check the “G” value

3. Checking Method
1)  Calculate aperture error using the following formula, and check that the aperture error is within the specification.

Aperture error = Average  G  value of checking lens (b) - Average  G  value of master lens (a) 

 

Aperture error = 0 

±

 12

2)  When the aperture error is out of specification, perform  4-2-2. Aperture Diameter Adjustment .

Equipment (Only the specific equipment is listed)
•  Adhesive bond (B-10)

1. Adjustment Method
1)  Detach the rear light interception tube (8948).
2)  Move the preset ring lever (preset lever) to fix the preset ring at the position where the aperture is open.

Rear Cover Barrel (8948)

3)  Move the preset ring right and left by slightly unscrewing the 2 screws and move them laterally.
4)  Move the 2 screws right and left, looking into the light source from the rear ball side, time-tune aperture diameter in mind aperture er-

ror, and tighten two screws.

Apply the bond
(B-10)

Two screws

5) Perform the 4-2-1. Check of Aperture Diameter  and repeat steps 1) to 4) until the aperture tolerance meets the specification.
6)  After completing the adjustment, apply bond (B-10) to heads of 2 screws tightened in step 4).

Setting of the Flange Back (f F) measuring instrument.

Equipment
•  1000 mm Collimator
•  Flange Back Tester
• A-mount Attachment
•  Flange Back Gauge (43.50 mm)

1. Preparations
1)  Set the equipment as shown in the Fig. 4-3-1.

 

Flange back gauge (43.50 mm)

A-mount attachment

Objective lens (10x)

Dial Gauge (Min. scale: 0.01 mm)

Scale ring

Eyepiece lens (7x)

Eyepiece ring

4-5

SAL18135 (3.5-5.6/18-135 SAM) (DT18-135mm F3.5-5.6 SAM)

2)  Looking through the eyepiece lens, turn the eyepiece ring of the flange back tester so that cross line or scale in the view is the sharp-

est.

3)  Attach the flange back gauge (43.50 mm) securely to the A-mount attachment and hold them together.
4)  Turn the focusing knob of the flange back tester so that fine scratches on the flange back gauge (43.50 mm) is the sharpest.

Turn the knob in the direction of the arrow of Fig. 4-3-2 for correct reading.

 

Focusing knob

Focus on fine lines on the surface.

Always turn the knob in the arrow
direction for correct reading.

5)  Turn the scale ring of the dial gauge until the long pointer indicates  0 .

This position is the flange back (f F) = 43.50 mm.

 

Memorize the position of short-pointer.

1)  Attach the checking lens to the flange back tester, and set the 1000 mm collimator.

 

1000 mm collimator

Checking lens

2)  Set the focus ring of the checking lens to 

∞

 (infinity) index or near 

∞

 (infinity)  and adjust the optical axis, observing the microscope 

so that the chart can be seen in the center.

3)  Turn the focusing knob of the flange back tester until the chart image comes into focus.
 

Also check the optical axis aligns with the chart center. (Refer to Fig. 4-3-4.)
Note: 

Figure shows example. The cause depends on individual lens.

 

Optical Alignment
Best alignment

Incorrect aligned
e.g. As the focusing knob is turned, the chart may appear blurry as illustrated.
The cause depends on individual lens.

4)  Perform Step (1) through Step (6) and ensure that the AS and CB values are within specifications. 

  If the specification is  CB  only, steps 1 to 3 are not required.

 AS 

(astigmatism)

 

The phenomenon where the flare on the ring chart appears in a cruciform shape with the ring chart in the sharpest focus. (Fig. 4-3-5 (a))

(1)  Turn the focusing knob until the flare becomes minimum between two approximately opposite points on the ring chart edge (as 

shown with the arrows in Fig. 4-3-5 (b)), and then read the dial gauge value. <A>

(2)  Turn the focusing knob until the flare becomes minimum between two points with the phase of the flare rotated by 90 degrees 

from the above condition (as shown with two arrows in Fig. 4-3-5 (c)), and then read the dial gauge value. <B>

(3)  Calculate the AS value (absolute difference between <A> and <B>) and ensure that it is within specifications.
 

AS value = <A> - <B>

 

CB (Center Blur)

 

The phenomenon where the flare on the ring chart trails in one direction with the ring chart in the sharpest focus. (Fig. 4-3-5 (d))

(4)  Turn the focusing knob until the ring chart edge in the direction of the maximum flare is in the sharpest focus (as shown with 

the arrow in Fig. 4-3-5 (e)), and then read the dial gauge value. <C>

(5)  Turn the focusing knob until the ring chart edge, opposite 180 degrees from the above condition (as shown with the arrow in Fig. 

4-3-5 (f)) is in focus, and then read the dial gauge value. <D>

(6)  Calculate the CB value (absolute difference between <C> and <D>) and ensure that it is within specifications.
 

CB value = <C> - <D>

 

(1)

(1)

(2)

(2)

(5)

(4)

AS

E

D

F

H

G

I

CB

CB (center blur)

0.19 mm or less

AS (AS on the axis)

0.14 mm or less

5)  If the specifications of CB and AS are not satisfied, perform the  4-3-2. Optical Axis Adjustment .

1.  If the optical axis does not meet the specification, replace the following parts.

①

  A-1849-455-A 

1ST LENS ASSY

②

  A-1849-503-A 

OPTICAL BLOCK FOR SERVICE

4-6

SAL18135 (3.5-5.6/18-135 SAM) (DT18-135mm F3.5-5.6 SAM)

Setting of Lens Test Projector.

Equipment
•  Lens Test Projector and Variable Transformer (Output voltage: AC 100 V)

Connect the variable transformer (Output voltage: AC 100 V) to the lens test projector.

• A-mount Attachment
•  Screen (Art paper)
• Tape Measure
•  Plane Mirror (For SLRs)

1. Preparations
1)  Perform the following steps (1) to (3), and incorporate the internal lenses of the lens test projector according to the checking focal 

length.
(1)  Open the lid of the lens test projector.
(2)  Pull up and turn the fixed levers on the right and left sides of the lens test projector.
(3)  Remove or insert the lens.

Be sure to have the right position and direction of the lens.  

 

Lens test projector

Incorporate of the lenses
according to the checking focal-length (f).

Lens

Fixed lever

Fixed lever

Lid

f=18 to 35 mm

f=35 to 100 mm

f=100 to 200 mm

f=200 to 300 mm

Heat-absorbing filter 

Chart

Chart

Chart

Chart

Filament

Filament

Filament

Filament

2)  Attach the checking lens to the lens test projector, and set the equipment as shown in Fig. 4-4-2.
3)  Turn the fan switch of the lens test projector to ON, then turn the lamp switch to ON.  

 

Distance

Lens test projector

Chart

Fan switch

Lamp switch

Plane mirror

Screen

A-mount attachment

Checking lens

F

L

4)  Turn the focus ring of the checking lens until the chart image projected on the screen is the sharpest at the center (y  = 0).
5)  Set the plane mirror to the center of the projected image (y  = 0), and adjust the projector position so that the mirror reflects the light to 

the center of the lens.

2.  Projective Resolving Power Checking Method
1)  Turn the focus ring of the checking lens until the chart image projected on the screen is the sharpest at the center (y  = 0).
2)  Read the number of the smallest pitched lines at the center (y  = 0).

 

The number represents for lines per mm.

Sagittal (S)

Meridional (M)

3)  Rotate the mount rotational plate of the lens projector while observing y  = 9, y  = 12, y  = 15 or y  = 18 and stop it at the location 

where the projective resolving power is worst (low).

 

Read the number of the smallest pitched lines (both sagittal and meridional: 3 lines) at the peripheral point.
Note: 

When reading the number of the smallest pitched lines, be careful of the spurious resolution.

Spurious resolution is the reversed image of 2 or 4 lines which appears on screen when focus is beyond maximum revolving power as shown 
in Fig. 4-4-4.

 

 

Do not confuse spurious resolution for the smallest pitched lines.

 

Correct resolution

Spurious resolution

4-7

SAL18135 (3.5-5.6/18-135 SAM) (DT18-135mm F3.5-5.6 SAM)

4)  Change the focal length and projected length of the checking lens. (In case of the zoom lens), project the S image and the M image at 

each focal point/projected length and confirm that the number of resolution satisfies the specification of the Table 4-4-1.

Focal length f 

(mm)

Distance (m)

Number of the smallest pitched lines (lines/mm)

Center (y  = 0)

Peripheral (y  = 9)

Peripheral (y  = 12)

S

M

S

M

18 (W)

1.08

100 lines or 

greater

40 lines or 

greater

32 lines or 

greater

32 lines or 

greater

25 lines or 

greater

50 (M)

3.00

135 (T)

8.10

5)  Check the projective resolving power. If the projective resolving power does not satisfy the specification, perform  4-4-2. Projective Re-

solving Power Adjustment (Partial Defocus Adjustment) .

Check the projective resolving power. If it does not meet the specification, adjust the projective resolving power (partial defocus adjustment) 
in the following procedure.

1.  Detach the 1st lens sheet and the 1st lens ring.
2.  Turn the 1st lens assy 120 degrees to assemble it and adjust the 1st lens assy.

1st Lens Assy

1st Lens Sheet (8948)

1st Lens Ring (8948)

120°

3.  If the projective resolving power does not meet the specification even by turning the 1st lens assy, replace the 1st lens assy.
4.  If the specified value is still not met, replace the product.
 

For how to take actions, refer to  1-5. NOTE ON REPLACEMENT OF SERVICE EXCLUSIVE OPTICS BLOCK .

5.  Recheck the projective resolving power and check that it meets the specification.

This section describes how to check the focus shift generated when the focal length is changed by zooming and how to adjust the focus 
shift and flange back.

Equipment
•   1000 mm collimator
•   Flange back tester
•  

A-mount attachment

•   Flange back gauge (43.50 mm)
•  Adhesive Bond (B-110)

Preparation
1. Perform 1. Preparation  of  4-3. OPTICAL AXIS CHECK/ADJUSTMENT .

1.  Focus Shift (Focal Distance) Check
1)  Set the zoom to the TELE end (135 mm).
2)  Set the flange back tester to  44.56 mm  by rotating the knob.
3)  Adjust the focus by rotating the focus ring, starting with the NEAR end.
4)  By rotating the zoom from TELE to WIDE and from WIDE to TELE, check that it meets the specification at each focal distance.

  Do not rotate the focus ring.

Focal length f (mm)

Flange back value f F(mm)

135

44.21 - 44.93

100

44.26 - 44.88

70

50

35

24

18

44.47 - 44.67

5)  In case that the flange back value (f F) does not meet the value in Table 4-5-1, perform  4-5-2. Focus Shift (Focal Distance)/Flange 

Back (f F) Adjustment .

2.  Flange Back (f F) Check
1)  Set the zoom to the TELE end (135 mm) and the focus to the over infinity end.
2)  Adjust the focus by rotating the knob of flange back tester and read the flange back value.

Focal length f (mm)

Flange back value f F(mm)

135

48.60 

±

 0.59 (48.01 - 49.19)

18

44.74 

±

 0.08 (44.66 - 44.82)

3)  In case that the flange back value (f F) of checking lens does not meet the specification in Table 4-5-2, perform  4-5-2. Focus Shift (Fo-

cal Distance)/Flange back Adjustment .