How Can a Near Object Be Focused While Looking at Distant Objects?

  • Thread starter Thread starter jstwinkles
  • Start date Start date
  • Tags Tags
    Focus
AI Thread Summary
To focus on a near object while also viewing distant objects, a small convex lens can be effective. This type of lens allows for simultaneous focus on both close and far objects, as demonstrated by its use in prismatic compasses. The discussion highlights the practicality of using such lenses for accurate readings without sacrificing clarity. Alternatives like bifocals were also mentioned but not elaborated on. Overall, a small convex lens is a recommended solution for this optical challenge.
jstwinkles
Messages
2
Reaction score
0
Hi, I have what might seem like an odd question. Suppose that someone is looking at an object in the distance, and there is an object placed about an inch in front of one of the person's eye. Obviously, this object would appear out of focus. My question is this: how would one bring this object into focus so that when the person is looking at distant objects it appears in focus? Could a small positive fresnel lens be used? If not, any ideas on how to go about doing this or any alternatives? Sorry if this sounds like a vague question, I have relatively little experience in optics.

Thanks ahead of time.
 
Physics news on Phys.org
A small convex (magnifing) lens does the trick. For example an prismatic compass uses such a lens to allow the user to view the moving compass card (a couple inches from the eye) and a landmark in the distance (miles away) at the same time for accurate readings.
 
jstwinkles said:
Hi, I have what might seem like an odd question. Suppose that someone is looking at an object in the distance, and there is an object placed about an inch in front of one of the person's eye. Obviously, this object would appear out of focus. My question is this: how would one bring this object into focus so that when the person is looking at distant objects it appears in focus? Could a small positive fresnel lens be used? If not, any ideas on how to go about doing this or any alternatives? Sorry if this sounds like a vague question, I have relatively little experience in optics.

Thanks ahead of time.

bifocals?
 
drummin said:
A small convex (magnifing) lens does the trick. For example an prismatic compass uses such a lens to allow the user to view the moving compass card (a couple inches from the eye) and a landmark in the distance (miles away) at the same time for accurate readings.

Thanks, drummin, that's exactly what I needed to know! I appreciate it.
 
drummin said:
A small convex (magnifing) lens does the trick. For example an prismatic compass uses such a lens to allow the user to view the moving compass card (a couple inches from the eye) and a landmark in the distance (miles away) at the same time for accurate readings.

Very interesting. I did not know that could be done. Thanks.
 

Thread 'Need help understanding particle physics and quantum physics'

So I know that electrons are fundamental, there's no 'material' that makes them up, it's like talking about a colour itself rather than a car or a flower. Now protons and neutrons and quarks and whatever other stuff is there fundamentally, I want someone to kind of teach me these, I have a lot of questions that books might not give the answer in the way I understand. Thanks
View full post »

Thread 'Raman Spectroscopy help'

I am attempting to use a Raman TruScan with a 785 nm laser to read a material for identification purposes. The material causes too much fluorescence and doesn’t not produce a good signal. However another lab is able to produce a good signal consistently using the same Raman model and sample material. What would be the reason for the different results between instruments?
View full post »

Similar threads

I Optical Tweezer Laser Focus/Alignment Troubleshooting
Replies
0
Views
2K
Can Math Model Real-World Camera Focusing Dynamics?
Replies
1
Views
1K
Stargazing Level of details in prime focus vs eyepiece images
5
Replies
226
Views
15K
I Steam punk, Field of view including the eye
Replies
4
Views
2K
A "Looks" of gravitational wave emissions for an eclipsing ternary compact object?
Replies
1
Views
977
Stargazing Is There an Unidentified Object Near the Horsehead Nebula?
Replies
14
Views
2K
Need to Refocus Projected Image Through Microscope Objective
Replies
4
Views
3K
I Why Isn't My OLED Screen Image at Infinity in My HUD Setup?
Replies
2
Views
5K
B Star like object travels in a zigzagging pattern relative to other stars
Replies
47
Views
7K
I Question about geometrical engineering (placeholder name)
Replies
32
Views
2K

Hot Threads

Recent Insights

Back
Top