Simple Lens Diagram for a Camera

Smythe

A simple camera has a converging lens and the image is in focus on the screen.

The paths of three rays from the tree to the lens are shown in the attached diagram.

Complete these paths to show the formation of the image on the film.

I have attached the diagram for the above question.

I think after I have placed a ruler on the central line and continue this line to the screen, I would then draw the top line straight to meet where the central line touches the screen.

Then with the bottom line I would draw this up to ground level.

When I draw a little sketch of the tree on the screen this sketch would be of an inverted tree.

How does this sound?

Thank you

FarmerGreen

Imagine a tiny hole between the tree and the screen.
Light from the middle of the tree passes through to the middle of the screen.
From the top of the tree through the hole to the bottom of the screen
Like wise from the bottom to the top.
You can prove this to youself with a box, a small hole at one end and a piece of paper at the other.

FISMA

Excellent biconvex lens applet
http://micro.magnet.fsu.edu/primer/java/lens/bi-convex.html

FISMA

Smythe,
If you are new to this game you are going to be confused by taking multiple points on the same object - like the top and the bottom of the tree.

Take the top of the tree and see what happens.

Also, where is the tree: outside C, between C and F, at C, at F or inside of F. In order to explain, I need to know where the object is. I would guess that if you are taking a picture of a tree that the object is outside of C.

There's three rays you need to know - go to the applet right now.

Ray one: a horizontal line that enters the lens (LHS), exits through the focal point(RHS).

Ray two: sort of the opposite to the above, a ray that goes through the RHS f exits horizontal

Ray three - draw a line through the center of the lens.

All you need is two of the above and you can draw a simple image.

Check the applet out...

mikhail

Smythe wrote: »

A simple camera has a converging lens and the image is in focus on the screen.

The paths of three rays from the tree to the lens are shown in the attached diagram.

Complete these paths to show the formation of the image on the film.

I have attached the diagram for the above question.

I think after I have placed a ruler on the central line and continue this line to the screen, I would then draw the top line straight to meet where the central line touches the screen.

Then with the bottom line I would draw this up to ground level.

When I draw a little sketch of the tree on the screen this sketch would be of an inverted tree.

How does this sound?

Thank you

That's correct, though a strange way of doing it.

As others have suggested, it's unusual to draw lines which aren't parallel to the optical axis, don't pass through the lens at the optical axis, or don't pass through the focal point.

Delphi91

All you really need to find is the image of the top and the bottom of the tree.

The basic rules for drawing ray diagrams are as follows:

1. A light ray that comes from the object and passes through the focal point, will strike the lens and leave it travelling parallel to the optical axis. (Ray No. 1 in diagram)

2. A light ray that comes from the object travelling parallel to the optical axis will strike the lens and leave it passing through the focal point (Ray No. 2 in diagram)

3. A light ray that leaves an object and travels straight through the centre of the lens will continue through the lens without being deflected (Ray No. 3 in diagram)

The light ray from the bottom of the tree will follow rule 3 above.

Once you plot those rays, you can draw pretty much any ray diagram.


Hope this helps.