Term
Real objects have what kind of vergence? Virtual objects? 

Definition
Real objects: Divergence/ negative vergence Virtual objects: Convergence/ positive vergence. 


Term
If light exits with positive or convergence will it form a real or virtual image? 

Definition


Term
What is an umbra? What is a penumbra? 

Definition
Umbra = full shadow (shadow is absence of light) Penumbra = partial shadow 


Term
What is the power of a planoconvex thin lens in air with n'=1.56, whose curved surface has a radius of curvature of 6cm? 

Definition


Term
Define the secondary Focal point. Where is it located for + lenses?  lenses? 

Definition
location of the image point when light from infinity strikes the lens. + > to the right, real image  > to the left, virtual image 


Term
Define primary focal point. 

Definition
the location of the object point from which light can leave as plane waves. @ infinity. 


Term
Where is the nodal point on a SSRI? 

Definition
Center of curvature > the point through which light passes undeviated. 


Term
What is the lateral mag for an object height of 3cm and an image height of 6cm? 

Definition


Term
You look under water (n=1.50) and see a dinosaur 5 m below. What is its apparent depth? 

Definition
Apparent depth = d/n = 3.33 m Things look closer than they actually are in water! 


Term
When going to a higher n where does the angle of refraction bend? When going to a lower? 

Definition
Higher > bends towards normal Lower > away from normal 


Term
What property of the cornea does Gonio overcome? What is this principle? 

Definition
Total internal reflection  when going to a lower refractive index there will be a critical angle such that angle angle will be totally reflected internally. Any light incident at an angle greater than this critical angle will also be reflected internally. 


Term
In our handy dandy step along equation, the sign is positive or negative when going from the corneal to spectacle plane? 

Definition
Positive: cornea  spec Negative: spec  cornea 


Term
What does the image of the human eye look like? 

Definition


Term
As you increase n, what happens to vergence? Increase or decrease? 

Definition
Increasing n increased the change in vergence 


Term
In what case does equivalent power become just the sum of the surface powers? 

Definition


Term
What are prescriptions specified using? 

Definition
Back vertex power. Also how a lens is red in lensometry 


Term
What is the back vertex power? 

Definition
vergence of light exiting the optical system given that plane waves entered 


Term
In what case do the principle points and nodal points coincide 

Definition
If the lens is surrounded on both sides by the same material. n1=n3, f = f' 


Term
What does the aperture stop limit? What is the aperture stop in the eye? 

Definition
limits Amount of light that can enter the system. The pupil is the aperture stop in the eye 


Term
What does the field stop limit? What do the aperture stop and field stop together limit? 

Definition
Field stop limits the size of the object that can be images. The aperture stop and the field stop limit the field of view 


Term
What is the entrance pupil? What is the entrance pupil in the eye? 

Definition
The entrance pupil is the image of the aperture stop formed by all the lenses that lie in front of it. In the eye: View of the iris through the cornea 


Term
If you increase the F#/focal ratio of a camera, will more or less light enter the system 

Definition
Decreases. f/ = f/D (D is the diameter of the entrance pupil) 


Term
What is the entrance port? 

Definition
The image of the field stop formed by lenses in front of it 

