Spherical and aspherical mirror: 7 key differences for car owners

When it comes to optics in a car - be it side mirrors, interior rearview mirror or lenses in headlights - many people come across the terms spherical and aspherical mirror, but they don’t always understand what their fundamental difference is. Meanwhile, the choice between these types of optics directly affects visibility, driving safety and even parking comfort. Spherical mirrors, familiar to everyone from the classic “round” models, distort space at the edges, while aspherical (or “panoramic”) ones provide a wider viewing angle without severe distortion.

In this article we will look not only physical differences between these types of mirrors, but also their practical application in cars - from budget Lada Granta up to bonus BMW 7 Series. You'll learn why aspherical mirrors have become the standard on modern cars, how to properly adjust them, and when spherical optics may be preferable. And also - We will reveal the myth about “blind spots” and show how to minimize them using a combination of different types of mirrors.

1. What is a spherical mirror: operating principle and features

A spherical mirror is optical element with uniform surface curvature, the shape of which is part of a sphere. Such mirrors have been used in cars since their inception and are still found in budget models or as interior rear view mirrors. The main feature of spherical optics is equal magnification over the entire area, which simplifies the perception of distances, but narrows the viewing angle.

In automotive practice, spherical mirrors are most often installed:

• 🔹 Inside the cabin - like a central rear view mirror (for example, in Renault Logan or Kia Rio older generations).
• 🔹 On external side mirrors - in cheap trim levels or retro cars (for example, VAZ 2107).
• 🔹 In headlights - like reflectors in halogen lamps (for example, in Opel Astra H).

The main disadvantage of spherical mirrors is limited viewing angle (usually up to 15–20°). This means that the driver is forced to turn his head to see cars in adjacent rows or cars parked to the side. In addition, fish eye effect (distortion at the edges) of spherical mirrors is minimal, but they give a more accurate idea of the distance to objects.

⚠️ Attention: If your car is equipped only with spherical side mirrors, always turn your head 90° when changing lanes - the “blind spot” in such mirrors can hide a motorcyclist or cyclist.

2. Aspherical mirror: how does it work and why is it better?

Aspherical mirrors (sometimes called "panoramic" or "wide angle") have uneven surface curvature, which increases from the center to the edges. This allows you to expand the viewing angle to 45° or more without strong distortion in the central zone. Such mirrors have become standard on modern cars since Volkswagen Golf IV (1997) and are common today even in budget models like Hyundai Solaris.

Advantages of aspherical optics:

• 🔍 Wide viewing angle — more space is visible on the sides and behind.
• 🚗 Fewer blind spots — makes it easier to maneuver in heavy traffic.
• 🎯 Clarity in the central zone — objects in the center of the mirror are displayed without distortion.
• 💡 Compatible with driver assistance systems (for example, BLIS in Volvo or Lane Assist in Audi).

However, aspherical mirrors also have disadvantages:

1. Objects at the edges appear furtherthan it actually is (this can be misleading when parking).
2. The cost is higher than that of spherical analogues (especially for heated and electric mirrors).
3. Requires precise adjustment - if adjusted incorrectly, distortion increases.

3. Comparison of spherical and aspherical mirrors: table of key parameters

To clearly show the differences between the two types of optics, we have compiled a comparison table. Pay attention to the parameters that directly affect driving safety:

Parameter	Spherical mirror	Aspherical mirror
Viewing angle	15–20°	30–45° (depending on curvature)
Distortion at the edges	Minimum	Moderate (increases towards the edges)
Distance estimation accuracy	High	Medium (objects at the edges appear further away)
Blind Spots	Large (up to 2–3 meters from the side)	Minimum (0.5–1 meter)
Cost	Low	High (30–50% more expensive)
Application in automobiles	Budget models, retro cars, interior mirrors	Modern cars (since 2000s), premium brands

The table shows that aspherical mirrors win in most respects, but their high cost and the need to get used to distortions can become an obstacle for owners of old cars. For example, when replacing a spherical mirror with an aspherical one in Toyota Corolla E120 (2002–2007) the mounts may need to be modified, as the shape and size of the mirrors are different.

4. How to determine the type of mirror in your car?

Not all drivers know which mirrors are installed in their car. You can check this in several ways:

1. Visual inspection:
   • 🔍 The spherical mirror has uniform round shape (like a ball).
   • 🔍 Aspheric often has flat or elongated shape with the inscription "Objects in mirror are closer than they appear" (“Objects in the mirror are closer than they appear”).
2. Distortion test:
   • Bring your hand to the edge of the mirror. If she seems greatly enlarged or distorted - This is an aspherical mirror.
   • If the image remains proportional, it is spherical.

Checking the viewing angle:

• Sit in the car and look in the side mirror. If you see rear bumper part - aspherical mirror.
• If the view is limited only to the space behind, it is most likely spherical.

On some vehicles (for example, Ford Focus III or Skoda Octavia A7) are installed combination mirrors: The main part is aspherical, and the small segment at the bottom is spherical (for accurate estimation of parking distance). Such mirrors are marked with a dividing line.

What does the inscription on aspherical mirrors mean?

The inscription "Objects in mirror are closer than they appear" (or its equivalent in other languages) warns that due to the wide viewing angle, objects at the edges of the mirror appear further than they actually are. This is due to optical distortion, which increases towards the edges of the aspherical surface.

5. Which mirrors are better to choose: spherical or aspherical?

The choice between spherical and aspherical mirrors depends on car type, driving style and budget. Here are recommendations for different cases:

• 🚗 For city driving and parking:

  Optimal aspherical side mirror + spherical internal. This will give you a wide view when maneuvering and an accurate estimate of the distance when parking.

• 🏁 For highway and high-speed driving:

  Better combination of aspherical main mirror and a small spherical segment (as in Mercedes-Benz E-Class). This will help control overtaking cars without losing accuracy.

• 💰 For budget repairs:

  If the original aspherical mirrors are too expensive (for example, for Mazda 3 BK), can be installed universal aspherical from trusted brands: HELLA, Bosch or Mitsuba.

• 🏎️ For vintage cars:

  Spherical mirrors are better suited - they will retain the original appearance and will not require modifications to the mounts.

⚠️ Attention: When replacing mirrors with aspherical ones in cars older than 2005, check compatibility with the heating system. Some aspherical mirrors require a separate power supply due to the different resistance of the heating element.

Ensure compatibility with mount|Check for heating (if needed)|Pay attention to viewing angle markings (e.g. 30° or 45°)|Consult an auto electrician if power mirror-->

6. How to properly adjust aspherical mirrors?

Aspherical mirrors require more precise settings, than spherical, due to distortion at the edges. Here are step-by-step instructions for side mirrors:

1. Horizontal adjustment:

   Sit in the driver's seat and lean slightly to the left (for the right mirror) or to the right (for the left). Should be visible in the mirror small part of the rear wing (1–2 cm) - this will help estimate the distance to the curbs.

2. Vertical adjustment:

   The horizon should divide the mirror approximately in half. If too much sky or asphalt is visible, adjust the tilt using the lever or motor (depending on model).

3. Checking your blind spots:

   After setting up, ask an assistant to stand behind the car at a distance of 2-3 meters and slowly move to the side. It should remain visible in the mirror until it disappears behind the stern.

For the internal aspherical mirror (if installed), the following rule applies: the rear window should be completely reflected in it. If your car has a mirror with the function auto-dimming (auto dimming), make sure the sensors are not covered by stickers or hanging accessories.

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Properly adjusted aspherical mirrors should cover at least 70% of the blind spots, leaving only a small sector directly behind the pillars.

7. Frequent errors when using aspherical mirrors

Even experienced drivers sometimes make mistakes when using aspherical optics. Here are the most common of them:

• 🚫 Ignore distortion:

  Many people forget that objects at the edges of the mirror appear further away. This may lead to collision when changing lanes, if you do not take into account the actual distance.

• 🔧 Incorrect adjustment:

  If the mirror is adjusted too low or high, the driver loses visibility of the rear pillars. The optimal tilt angle is when the horizon line is visible in the mirror.

• 💨 Neglect of cleaning:

  Aspherical mirrors react more strongly to dirt than spherical ones. Dust, raindrops or snow distort the view and increase optical defects.

• 🔌 Self-replacement without electrical check:

  When installing heated aspherical mirrors or turn signals, it is important to check heating element resistance (usually 5–10 ohms). Failure to comply may result in a blown fuse.

To avoid these mistakes, monitor the condition of your mirrors and check their settings regularly. For example, after washing or rain, wipe the mirrors microfiber cloth - this will remove streaks that increase distortion.

FAQ: Answers to frequently asked questions

Is it possible to install an aspherical mirror instead of a spherical one on an old car?

Yes, but you need to take into account a few nuances:

1. Check mount compatibility — some aspherical mirrors have a different base shape.
2. If the mirror is powered, you may need to replacing the control unit.
3. For models before 2000 (for example, VAZ 2109) easier to choose universal aspherical mirror with manual adjustment.

Why do cars appear further away in an aspherical mirror than they actually are?

This is due to nonlinear increase along the edges of the mirror. The aspherical surface “stretches” the image to the sides, creating the illusion of distance. To get used to it, practice estimating the distance in a parking lot with an assistant.

Which mirrors are better for parking: spherical or aspherical?

For parking optimal combination:

• 🔹 Aspherical side mirror - to control the space on the side.
• 🔹 Spherical interior mirror — for accurate estimation of the distance to objects behind.
• 🔹 Rear view camera (if available) - for a complete overview.

Is it possible to polish a scratched aspherical mirror?

No. Unlike spherical ones, aspherical mirrors have precise coverage, which is broken during polishing. If there are deep scratches, the mirror must be replaced. For minor damage you can use special pads (for example, from 3M).

Why are aspherical mirrors more expensive than spherical ones?

The price is determined by:

1. Complexity of production — aspherical surface requires precision processing.
2. Additional features — heating, turn signals, automatic dimming.
3. Materials - more durable and UV-resistant coatings are used.

The price difference can reach 30–50% (for example, the original aspherical mirror for BMW 5 Series costs ~8,000 rubles, and spherical – ~5,000 rubles).