Why is a telephoto lens considered to have a longer focal length than that of single?

In summary, a telephoto lens is considered to have a longer focal length due to its complex system of lenses and mirrors. It achieves this longer focal length by using a combination of a negative lens element in the front and a positive lens element in the back. A single lens cannot achieve the same magnification as a telephoto lens. The advantages of using a telephoto lens include the ability to capture distant objects with greater magnification and detail, a shallower depth of field, and the ability to compress the perspective of a scene. However, there are limitations to using a telephoto lens such as bulkiness, expense, and a narrower field of view.
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1. Why is a telephoto lens considered to have a longer focal length than that of a single convex lens?

A lens combination, such as a diverging and a convex lens, is referred to as a telephoto lens. Suggest why a telephoto lens is considered to have a longer focal length than that of a single convex lens.
 
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If you just look at a camera with a telephoto lens, the distance from the front of the lens to the sensor inside the camera is very large.
 

Related to Why is a telephoto lens considered to have a longer focal length than that of single?

1. Why is a telephoto lens considered to have a longer focal length than that of single?

A telephoto lens is considered to have a longer focal length because it uses a complex system of lenses and mirrors to create a longer effective focal length. This allows for a more magnified image to be captured, making distant objects appear closer.

2. How does a telephoto lens achieve a longer focal length?

A telephoto lens achieves a longer focal length by using a combination of a negative lens element in the front and a positive lens element in the back. This creates a long barrel design, allowing for a longer distance between the front and back elements, resulting in a longer focal length.

3. Can a single lens achieve the same magnification as a telephoto lens?

No, a single lens cannot achieve the same magnification as a telephoto lens. A single lens has a shorter focal length and limited magnification capabilities, while a telephoto lens has a longer focal length and can achieve greater magnification.

4. What are the advantages of using a telephoto lens?

The advantages of using a telephoto lens include the ability to capture distant objects with greater magnification and detail, a shallower depth of field for more artistic shots, and the ability to compress the perspective of a scene, making objects appear closer together.

5. Are there any limitations to using a telephoto lens?

One limitation of using a telephoto lens is that it can be bulky and heavy, making it less portable than other lenses. It also tends to be more expensive than single lenses. Additionally, telephoto lenses have a narrower field of view, making it more difficult to capture wide shots or fit multiple subjects into the frame.

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