1. ## Camera picture calculation:

Hi could someone please solve this with explanations, I am not very good at algebra. Thank you...

PROBLEM:

Camera
• Uses lens to focus object onto a sensor
• magnification m = image size / object size
m = v / u
where u=distance from object to lens
v=distance from lens to image plane
• focal length is distance from lens to
point where parallel rays converge

1/f = 1/u + 1/v thus f =um /(m+1)

For a camera with a sensor of
dimensions 10 mm wide by 10 mm high,
calculate the focal length required to
form an image over the sensor of an
object 20 cm wide by 20 cm high. The
object is placed 1m from the lens.

2. Originally Posted by sunny155
Hi could someone please solve this with explanations, I am not very good at algebra. Thank you...

PROBLEM:

Camera
• Uses lens to focus object onto a sensor
• magnification m = image size / object size
m = v / u
where u=distance from object to lens
v=distance from lens to image plane
• focal length is distance from lens to
point where parallel rays converge

1/f = 1/u + 1/v thus f =um /(m+1)

For a camera with a sensor of
dimensions 10 mm wide by 10 mm high,
calculate the focal length required to
form an image over the sensor of an
object 20 cm wide by 20 cm high. The
object is placed 1m from the lens.
1. Draw a sketch!

2. Convert all measures into cm (or mm, that doesn't matter. But all measures must have the same dimension)

3. You are dealing with isosceles triangles. First calculate v.

4. Now calculate f using the given formulas.