Logical Specs: Why Numbers are Blurry in Rear-View Mirrors

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In summary, the conversation discusses the issue of blurry vision while driving and how the use of spectacles can improve it. The individual has perfect near vision but anything beyond 20 feet is blurry. They also noticed that without glasses, the number plates of cars behind them appear blurry in the rear-view mirror, but become clear when they put their glasses on. The conversation then delves into the concept of mirrors and how they affect the perception of distance, with a demonstration of how objects appear closer in the mirror than they actually are.
  • #1
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Hi, I hope you can answer this question that is baffling me.
I now require spectacles for driving; anything more than 20 feet away is a blur.
But my near vision is perfect, so fine print from a book is no problem.
So why, without my spectacles on and looking in a rear-view mirror, which is approx 16 inches away and at head height, are the number plates of the cars behind blurry?
If I then put my new specs on the number plates are perfectly clear.
I tried my own off the cuff experiment, and stuck a sticker on the rear-view mirror with some writing on it, and without glasses it was perfectly clear, when I tried my specs the sticker’s text became distorted.
Thank you in advance
 
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  • #2
Look into a mirror, one at home preferably. Notice that you have to focus differently when you look at objects that are further or closer in the mirror. This is just like you would have to do if you turned around and looked at those same objects. The mirror doesn't make it look like the objects are the same distance away as the mirror is.
 
  • #3
The image that you see in a mirror is not in the plane of the mirror. It's behind the mirror, in fact it's the same distance behind the mirror as the original object is in front of the mirror.

15120205.jpg


This assumes a plane (flat) mirror. Curved mirrors are another matter.
 

1. Why are numbers blurry in rear-view mirrors?

The blurriness of numbers in rear-view mirrors is due to the way these mirrors are designed. Rear-view mirrors are convex, meaning they are curved outward. This curvature causes the reflection of objects to appear smaller and distorted, making it difficult to read numbers clearly.

2. Can this blurriness be fixed?

Unfortunately, the blurriness in rear-view mirrors cannot be fixed. It is a natural result of the mirror's design and cannot be altered. However, some newer cars may have anti-glare or anti-distortion technology in their rear-view mirrors to improve visibility.

3. Does this blurriness affect safety while driving?

The blurriness in rear-view mirrors may slightly affect safety while driving, but it is not a major concern. Drivers should always use caution and check multiple mirrors before making a turn or changing lanes, regardless of the clarity of the numbers in the mirrors.

4. Is this blurriness unique to rear-view mirrors?

No, the blurriness caused by convex mirrors is not unique to rear-view mirrors. It is also present in other curved mirrors, such as side-view mirrors and makeup mirrors.

5. Are there any tips for improving visibility in rear-view mirrors?

Yes, there are a few tips that can help improve visibility in rear-view mirrors. These include keeping the mirrors clean and adjusting them properly to eliminate any blind spots. Additionally, some drivers find that tilting the mirror slightly downward can help reduce the blurriness of numbers.

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