Question

The exposure time of a camera a lens at f/2.8 setting is 1/200 seconds. The correct time of exposure for f/5.6 setting is –

• A. 0.04 sec
• B. 0.20 sec
• C. 0.40 sec
• D. 0.02 sec

Answer 1

Answer: (D)

0.02 sec

Answer 2

(f. no)² µ t

$\left( \frac { 2.8 } { 5.6 } \right) ^ { 2 }$ =

t = $\frac { 1 } { 50 }$ = 0.02 sec