Focusing on Object K: Magnification & Adjustment of Focal Length

In summary, the problem involves a human eye lens with a far focal length of 40.1 mm and an object K at a distance of 1.69 m. The focal length needs to change to 41.0746 mm to focus on object K. The magnification for object K can be calculated using the equation -f2/f1=M. The mistake in the solution was due to the wrong placement of 1/x in the equation.
  • #1
haxxorboi
24
0

Homework Statement


Suppose the lens in a human eye has far focal length equal to f0 = 40.1 mm, for distant objects to be in focus.
A. An object K is 1.69 m from the lens. How much should the focal length change to focus on the object K?

B.What is the magnification ( = image size divided by object size) for the object K?


Homework Equations


1/di+1/do=1/f


The Attempt at a Solution


A. 1/1690+1/x=1/40.1
x=41.0746 mm
Thus, delta f = .9746 mm but that's wrong for some reason... but it's been a long week...

B. -f2/f1=M

Can someone help me out here?
 
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  • #2
haxxorboi said:
1/1690+1/x=1/40.1

it's been a long week...

Hi haxxorboi! :smile:

Shouldn't the 1/x be on the other side? :redface:
 
  • #3
*sigh* Yep, that'd be the issue... need either more sleep or more caffeine I guess...

Problem solved.

Thank you very much... I'm going to go take a nap...
 

1. What is object K and why is it important to focus on it?

Object K refers to the specific object or subject that you are photographing. It is important to focus on it because it is the main subject of your photo and having it in sharp focus can greatly enhance the overall quality of your image.

2. How does magnification affect the sharpness of the image?

Magnification refers to the size of the image on the camera's sensor. The higher the magnification, the more detail and sharpness will be captured in the image. However, it is important to note that too much magnification can also result in image distortion or blurriness.

3. What is the focal length and how does it impact the composition of the photo?

The focal length refers to the distance between the camera's lens and the image sensor. It impacts the composition of the photo by determining the angle of view and the magnification of the subject. A longer focal length can result in a narrower angle of view and a closer view of the subject, while a shorter focal length can capture a wider angle of view and a more distant view of the subject.

4. How do I adjust the focal length on my camera?

The method for adjusting the focal length varies depending on the type of camera you are using. For DSLR cameras, you can change the focal length by twisting the zoom ring on the lens. For mirrorless cameras, you can adjust the focal length by using the zoom function on the camera's touchscreen or control dials.

5. Is it better to use manual or autofocus when adjusting the focal length?

It ultimately depends on your personal preference and the situation you are shooting in. Autofocus can be helpful for quickly capturing moving subjects, but it may not always be accurate. Manual focus gives you more control over the focus and can result in sharper images, but it requires more time and practice to master.

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