Pupils And Stops And Related Effect

Question 1

Field of uniform illumination

Answer 1

• center plateau
• set of image points with the same illumination passing through the system
• the ray touches the edge of the field stop AND the aperture stop

Question 2

Measuring the angle of field of illumination

Answer 2

• the ray touches the field stop and the aperature stop
• split the triangle in 2 so you make a right angle
• tan (Fu/2)=(a-b)/dp

Question 3

Chief ray

Answer 3

The ray from an object point that is incident on the system pointing towards the center of the entrance pupil

Question 4

Marginal ray

Answer 4

The ray that just passes the edge of the aperture stop

Question 5

What angle is visually the smallest?

Answer 5

The field of uniform illumination

Question 6

Field of at least one-half illumination

Answer 6

• What is conventionally known as the field of view
• where the image starts to dim but not completely dark yet is the border of it
• field of at least 50% illumination

Question 7

What type of ray do you use to find the angle of field of 1/2 illumination?

Answer 7

Chief ray

Question 8

Measuring the angle of field of at least 1/2 illumination

Answer 8

• chief ray passes through touching the field stop but then passing through the center of the aperture stop
• tan (Fh/2)=a/dp
• draw line through center to create a right triangle

Question 9

What is the conventional field of view?

Answer 9

Field of at least one-half illumination

Question 10

Totally field of view

Answer 10

Field of more than 0% illumination

Question 11

Measuring the total field of view

Answer 11

• line from the top portion of the field stop to the bottom portion of the aperture stop
• half it so there is a right triangle
• tan (Ft/2)=(a+b)dp
• visually the largest angle when you draw it

Question 12

Field of view and eye relief

Answer 12

• line up with own eye to get max field of view

- line up entrance pupil of eye when exit pupil of system, you max field of view

Question 13

Eye relief

Answer 13

-the distance from the last surface of an eyepiece at which the users eye can obtain the full viewing angle

Question 14

What happens if the viewers eye is outside the distance from the last surface of an eyepiece?

Answer 14

A reduced field of view will be obtained

Question 15

The higher the magnification, and the larger the intended field of view…

Answer 15

The shorter the eye relief

-the stronger the lens, the closer your eye needs to be to get max field of view

Question 16

Vignetting

Answer 16

Fall-off in illumination for points away from the optical axis
-dim ring around pictures and field of view

Question 17

What if the eye relief is too short?

Answer 17

You cannot place your eye one the eye point, so vignetting may occur. Will have to take off glasses because the glasses will make your eye too far away