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Distance Reading of Master Lens

Image Magnifi-cation Ratio

Field Coverage (cm)

Distance from Lens Front to Subject (cm)

Exposure Factor

12 mm

infinity

0.24

10?15

ab. 21

1.5

0.5 m

0.35

6.9?10.3

ab. 16

1.8

20 mm

infinity

0.4

6?9

ab. 13

2

0.5 m

0.51

4.7?7

ab. 14

2.3

36 mm

infinity

0.72

3.3?5

ab. 7.7

3.0

0.5 m

0.83

2.9?4.4

ab. 7

3.4

12+20 mm

infinity

0.64

3.8?5.6

ab. 8.5

2.7

0.5 m

0.75

3.2?4.8

ab. 7.5

3.1

12+36 mm

infinity

0.96

2.5×3.7

ab. 6

3.9

0.5 m

1.07

2.3?3.4

ab. 5.5

4.3

20+36 mm

infinity

1.12

2.2?3.3

ab. 5.3

4.5

0.5 m

1.23

2?3

ab. 4.9

5

12+20+36 mm

infinity

1.34

1.8?2.7

ab. 4.5

5.6

0.5 m

1.47

1.6?2.4

ab. 4.2

6.1