Can You Focus on Two Distances at Once?

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SUMMARY

The discussion centers on the optical phenomenon of focusing on two different distances simultaneously, specifically in the context of viewing a mirror with water spots. The consensus is that it is impossible to see both the water spots and one's own reflection in focus at the same time due to the differing distances of the objects from the observer. The concepts of "depth of field" and "depth of focus" are crucial to understanding this limitation in human vision.

PREREQUISITES
  • Understanding of basic optics principles
  • Familiarity with the concepts of depth of field and depth of focus
  • Knowledge of object distance (p) and image distance (q) in optics
  • Experience with practical applications of mirror reflections
NEXT STEPS
  • Research the principles of depth of field in photography
  • Explore the differences between depth of field and depth of focus
  • Conduct practical experiments with mirrors to observe focus limitations
  • Study the human eye's focusing mechanism and its implications for vision
USEFUL FOR

This discussion is beneficial for students studying optics, photographers seeking to understand focus techniques, and anyone interested in the mechanics of human vision.

fridakahlo
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Homework Statement


You are standing approximately 2 m away from a mirror. The mirror has water spots on its surface. True or False: It is possible for you to see the water spots and your image both in focus at the same time.

Homework Equations


p=object distance
q=image distance

The Attempt at a Solution


I think this statement is false because the water spots are 'closer' to the mirror. Therefore, in my perspective, the reflection of the water spots in the mirror will be closer to me than my own reflection in the mirror.
Intuitively, my eyes won't be able to focus on two things (at different distances) 100% clearly, but why is that?
 
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Look up "depth of field" and "depth of focus" ... I'd try the bathroom mirror thing myself if I were you, check your understanding.
 

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