Snap Like A Pro: Smartphone Camera - Image Stabilization, Autofocus, Multiple Cameras, And Sensors

Image Stabilization - The Shaky-Hands Savior

Image stabilization is like having a personal butler for your camera. Its mission? To counteract those pesky shakes and jitters caused by unsteady hands or movements, resulting in sharper images and smoother videos. Think of it as a Zen master for your camera, keeping things steady.

In general, it is best to shoot a photo by placing the camera on a stable surface or stand, like a tripod. However, this is not always practical. When you shoot a picture by holding your smartphone in your hand, small movements (such as yaws, tilts, and rolls) of its camera resulting from the shakes of the hand during the exposure can cause a blur (the motion blur) in the output photo or a jitter in the frames of the output video. Image stabilization is the collective name given to the various techniques that reduce these unwanted effects in the output.

Below, we describe a few different types of image stabilization, and the various techniques and methods used for the purpose.

Electronic Image Stabilization (EIS) or Digital Image Stabilization

EIS is like having a digital sorcerer inside your camera. It processes the image in real-time, using the CPU and the software, to counteract any shakes and jitters. It doesn't involve physical movement like OIS.

Comparison of image stabilization techniques: 1 - Unstablized; 2 - Lens-based OIS; 3 - Sensor-Shift OIS; 4 - EIS.

In case of EIS, an accelerometer (sometimes together with a gyroscope) detects the small movements of the hand, and the camera software moves and rotates the image to counter those movements. For instance, if the phone detects that your hand has moved a bit toward the left, it would shift the captured image slightly toward the right. Clearly, this means that a small part of the image at the left and the right edges of the sensor has been discarded.

To allow for other movements (like up and down, and rolling), short strips of the sensor area at all four of its edges act as a buffer for the counter movements for stabilization, and are discarded in the final output. Thus, EIS involves processing (such as rotating, shifting, or applying other effects) and cropping the image, which affects the quality of the final output.

In case of a video, EIS processes the adjacent frames to keep a point with a high contrast at the same location within them, thereby smoothing out the vibrations during the transition between the frames. However, this may sometimes produce an output with movements that look unnatural.

The OnePlus Nord N200 uses EIS for smoother video recording, and the Samsung Galaxy S21 uses a combination of EIS and OIS. Manufacturers like Huawei also use AI (artificial intelligence) in the EIS to enhance the output and make it look more natural.

Pros of EIS: EIS is more compact and less power-hungry than OIS, making it a good fit for smartphones. It is quicker than OIS as it does not involve mechanical movements. Since it is implemented in the software, it can be upgraded without having to upgrade the device (the hardware) itself. It can also be used in conjunction with OIS for even better stability.

Cons of EIS: It may not be as effective in extreme situations, and there's a slight reduction in image quality as it crops and processes the image. The videos produced by EIS may have movements that look unnatural.

EIS is more cost-effective than OIS, making it a common choice for mid-range and budget phones. If you are a photo buff, and have to choose between OIS and EIS, our advice will be to go with the former.

5-Axis Gyro-EIS: A Mini Stabilizer Inside Your Phone

The 5-axis gyro-EIS ensures your videos are as steady as a Yoga master in a windstorm! Let's unravel this technological marvel and see how it compares to regular EIS.

How 5-Axis Gyro-EIS Works

As we read above, EIS is a technology used in smartphones and cameras to counteract the blurring and shaking that can occur when recording videos handheld. It works by cropping the frame slightly, and digitally adjusting the image to compensate for shakes and movements.

Now, add a gyroscopic sensor to the mix, and you get 5-axis gyro-EIS. This advanced stabilization technology takes EIS to the next level by incorporating gyroscopic sensors that detect movements along five different axes:

• Up-down
• Left-right
• Forward-backward
• Pitch: Imagine you're nodding your head up and down, like saying "yes". That motion is pitch. In technical terms, pitch refers to the rotation around a horizontal axis that runs from side to side, like the imaginary line that would run through your ears if you were standing upright. When your phone or any object tilts forward or backward, it's pitching.
• Yaw: Yaw, on the other hand, is like shaking your head from side to side, as if saying "no", even though 'yaw' sounds more like 'yeah'. It refers to the rotation around a vertical axis, as if you're turning left or right without tilting up or down. Yaw is akin to the movement of a compass needle when you change direction while standing still; it points in different directions as you turn. When your phone or any object rotates left or right while maintaining its horizontal position, it's yawing.

Essentially, it can compensate for a wider range of movements and shakes in multiple directions. By compensating for these movements, your device can provide smooth, steady footage, ensuring that your videos look great, no matter how you move or rotate your device.

Benefits of 5-axis Gyro-EIS

Here is why 5-axis gyro-EIS is awesome when recording videos:

• More Comprehensive Stabilization: The additional axes allow 5-axis gyro-EIS to stabilize a broader range of movements, providing smoother and steadier videos, even in challenging shooting conditions.
• Better Low-Light Performance: By compensating for shakes effectively, 5-axis gyro-EIS can result in clearer low-light videos, where shaky movements are more noticeable.
• Professional-Looking Videos: With this level of stabilization, your videos can have a more professional, polished look, akin to those shot with high-end video cameras and stabilizing equipment.

5-axis gyro-EIS provides superior results compared to regular EIS, especially when it comes to stabilizing videos in various real-world scenarios. Its ability to compensate for a wider range of movements makes it highly effective in delivering smooth, professional-looking videos, even when you're on the move.

So, if you fancy yourself as the next Spielberg of smartphone cinematography, 5-axis gyro-EIS is your secret weapon for creating stunning, shake-free videos that will leave your audience in awe!

Gimbal Stabilization

This is like having a mini-movie director in your camera. Gimbals are motorized stabilizers that keep your camera level and steady, even during dynamic movements, like when you're running while shooting a video. They offer even better stabilization than the Optical and the Hybrid Image Stabilization.

A gimbal with a smartphone

If your phone does not sport a native gimbal-like stabilization, you can use an external gimbal, that you can purchase separately. Used together with your phone's OIS or HIS, this will provide you exceptional stabilization, producing images that are free of blur and videos that do not shake.

Pros of Gimbals: Gimbal stabilization provides exceptional stability, making it perfect for professional video production or cinematic shots.

Cons of Gimbals: Gimbals can be bulky and require setup time. They are not typically used with smartphones but are common in dedicated video cameras and DSLRs. Some manufacturers like Vivo use a gimbal-like stabilization on some of their phone models.

Gimbal stabilization can be pricey, as a good-quality gimbal is costly.

How ISO, Image Stabilization, and Megapixels Affect the Overall Image Quality

Ah, the trio of image quality champions - ISO, image stabilization, and megapixels. They're like the Avengers of photography, each with their unique superpowers.

Check out this article to learn about the ISO and the megapixels (resolution).

ISO is your camera's sensitivity to light. A low ISO, like 100, keeps noise at bay and delivers crisp shots, but it's a bit of a diva in dim lighting. On the flip side, a high ISO, say 1600, is your low-light savior, but it can introduce grainy noise, like a sneeze during a quiet movie.

Image stabilization is the magic wand against shaky hands. Whether it's optical or digital, it's your go-to for keeping those sunset shots steady or for capturing the Milky Way without the star trails. But even the best wizards can't work miracles, so don't expect it to fix a full-on earthquake.

Ah, megapixels, the resolution royalty! They determine how much detail your camera can cram into a shot. More megapixels mean sharper images that can be enlarged to poster size without losing quality. But beware of the storage goblin - higher megapixels result in larger file sizes, and your phone might cry "storage full."

Autofocus - The Wizard of Sharpness

Autofocus (AF) is your camera's way of saying, "Hey, I got this! Let me focus on the right thing for you." It's like having a tiny photography wizard inside your camera, ensuring your images are sharp and crisp without you having to fiddle with manual focus.

In order to capture a great photo, you need to bring the main object of the photo into the focus. The autofocus feature of the camera does this for you automatically, guessing the object to focus and its distance from the camera. It then adjusts its various settings so as to create a depth of field that would make the object stand out with sharp contours and ample contrast.

Let's now unravel the mystical technologies used by the autofocus feature with a sprinkle of tech magic!

Phase Detect Autofocus (PDAF)

Now, let's bring out the ninja. Phase Detect AF splits the incoming light into two separate beams, comparing them to determine if they're perfectly aligned. If not, it knows how much adjustment is needed to bring them together. This happens lightning-fast, making it great for tracking moving subjects. It's like two ninjas high-fiving while keeping an eye on your subject.

Phase Detect Autofocus (PDAF) - The lens is focused: 1 - Too near; 2 - Correctly; 3 - Too far; 4 - Way too far.

Fast-moving subjects, beware! Phase Detect AF is your buddy for sports, wildlife, or any action-packed moments.

The technology behind PDAF consists of using photodiodes across the sensor. A photodiode is a semiconductor diode which, on being exposed to light, generates a potential difference or changes its electrical resistance, thereby allowing the camera to know the intensity of light falling on it. Now, the two beams of light falling on the diodes will be "in phase" when they have the same intensity. Any difference in the intensities of the beams gives the camera the amount by which to move the focusing element in the lens to bring the target image into focus.

While PDAF is pretty fast, it is slightly slower and less accurate than the dual-pixel autofocus.

So these are the most common autofocus marvels at your service! Whether you're chasing action, hunting for the perfect portrait, or just capturing life's moments, your camera's autofocus wizardry ensures those shots are sharp enough to make your eyes twinkle.

Anti-stroboscopic Sensor: Your Camera's Secret Superhero

The mysterious anti-stroboscopic sensor sounds like it's straight out of a sci-fi movie, but is actually a subtle yet crucial addition to the world of smartphone photography. At its core, an anti-stroboscopic sensor is designed to combat a phenomenon known as stroboscopic effect, which is essentially the visual illusion of motion or a flickering effect when capturing fast-moving subjects under artificial lighting, especially in low-light conditions.

Picture this: You're at a concert, and your favorite musician is going all out on the guitar solo. As you snap a photo, the powerful stage lights cause the guitar strings to appear as if they're vibrating or flickering in the image. This is where the anti-stroboscopic sensor steps in.

The sensor detects the frequency of the artificial lighting in the environment and synchronizes the camera shutter speed to it. By doing so, it minimizes the chances of capturing frames when the lights are in a phase that might cause the stroboscopic effect. The result? Crisp, clear images without any unwanted visual distortions.

Here is how the anti-stroboscopic sensor enhances your photography:

• Freezing Fast-Moving Action: Imagine you're into sports photography, capturing a fast-paced soccer match. The anti-stroboscopic sensor ensures that each frame freezes the action without introducing unintended visual artifacts. This is particularly handy when dealing with rapid movements where traditional shutters might fall short.
• Enhancing Low-Light Performance: In dimly lit environments, where artificial lighting tends to flicker, the anti-stroboscopic sensor helps maintain image quality. It ensures that your low-light shots remain sharp and devoid of distracting visual anomalies.
• Perfect for Concerts and Events: Concerts and events often involve dynamic lighting setups. The anti-stroboscopic sensor shines in such scenarios, preventing the flickering lights from playing tricks on your photos and allowing you to capture the essence of the performance.
• Ideal for Videography: While often associated with photography, the anti-stroboscopic sensor is equally beneficial for videography. It contributes to smooth and flicker-free video recordings, especially when shooting under varied lighting conditions.

In essence, the anti-stroboscopic sensor is a subtle yet powerful tool working behind the scenes to ensure that your smartphone photography and videography experience is free from the nuisances of flickering lights. It's one of those features you might not consciously notice, but you'll definitely appreciate the results it brings to your visual storytelling adventures!

Flicker Sensor

The flicker sensor is a nifty component that helps combat the annoying flicker effect you sometimes notice in photos and videos, especially when shooting under artificial lighting like fluorescent bulbs or LED lights. These light sources flicker at a frequency that can clash with the camera's shutter speed. They can produce flicker that is not visible to the naked eye but can affect image quality, resulting in those pesky dark bands in your otherwise Instagram-worthy shots.

The flicker sensor detects these rapid fluctuations in light intensity and adjusts the camera settings to compensate, preventing the appearance of banding or inconsistent lighting in photos and videos.

While the flicker sensor might sound like a distant cousin to the anti-stroboscopic sensor, they're not exactly the same party animals. The anti-stroboscopic sensor is more about tackling the flicker you might encounter when capturing moving objects under certain lighting conditions. Think of it as your camera's superhero cape against the visual disturbance caused by fast-paced action and lighting that loves to play hide-and-seek.

In essence, while both sensors have their roles in ensuring your photos and videos are as smooth and flicker-free as your favorite movie, they tackle slightly different aspects of the lighting puzzle. It's like having two guardians - one for still moments and another for dynamic scenes - ensuring your visuals are top-notch in any scenario.

The flicker sensor has multiple applications in photography. By analyzing the color temperature of the ambient light, it helps the camera to adjust white balance more precisely. This ensures that colors are rendered accurately, whether you're shooting in natural sunlight, under artificial lighting, or in mixed lighting conditions. The result is more natural and true-to-life colors in your photos and videos. In environments with artificial lighting, such as offices, malls, or at night, the flicker sensor minimizes the impact of light flicker. This leads to clearer, more consistent images without the unwanted artifacts that flicker can cause.

The flicker sensor helps the camera system to better understand and adapt to low-light conditions by providing accurate information about the light spectrum. This can improve the performance of other camera features, such as HDR and night mode, ensuring that images are well-exposed and detailed, even in challenging lighting situations. For professional photographers and videographers, the ability to control and compensate for lighting conditions is critical. The multispectral color temperature sensor allows for more precise manual adjustments and fine-tuning, enabling users to achieve the desired look and feel in their shots.

The inclusion of a multispectral color temperature sensor, or flicker sensor, adds a significant advantage to a camera setup. By accurately detecting and compensating for light conditions and flicker, this sensor ensures that colors are rendered accurately, images are consistent, and the overall quality of photos and videos is enhanced. Whether you're shooting in natural light, artificial light, or mixed lighting conditions, the flicker sensor helps the camera deliver professional-grade results, making it a versatile and powerful tool for both casual and professional users.

From Photons to Digital Image - How the Smartphone Camera Works

Ah, the behind-the-scenes magic of turning a camera capture into a digital image! Let's peel back the curtain and reveal the tech wizardry at play:

1. Capturing the Image

   When you press the camera button on your smartphone, a few key actions happen in rapid succession:

   • Exposure: The camera lens opens (the aperture), and the shutter (the electronic shutter in a smartphone) allows the light to hit the image sensor.
   • Sensor Activation: The image sensor, often a CMOS (Complementary Metal-Oxide Semiconductor) or CCD (Charge-Coupled Device) chip, receives this incoming light.
   • Pixel Gathering: Each pixel on the sensor collects photons (light particles) and converts them into electrical signals. The intensity of the light determines the strength of the electrical signal.

2. Image Processing

   Once the sensor has captured the image as an array of electrical signals, the smartphone's image processor goes to work:

   • Digitalization: The analog electrical signals are converted into digital data. Each pixel's signal strength is represented as a number, forming a grid of values that make up the image.
   • Color Information: If it's a color photo, the camera's color filter array (CFA) and demosaicing algorithms help determine the color of each pixel. These algorithms use the data from the neighboring pixels to fill in the color information.
   • White Balance: The image processor adjusts the white balance to ensure an accurate color representation. It aims to make whites appear truly white, regardless of the lighting conditions.
   • Image Enhancement: The processor may apply various enhancements, such as sharpening, noise reduction, and contrast adjustments, to improve the image's overall quality.

3. Compression

   To save storage space, the smartphone often uses image compression algorithms, such as the one used in the JPEG (Joint Photographic Experts Group) images. These algorithms are lossy and they remove redundant or less important image data while preserving the essential details. This results in a smaller file size without significantly sacrificing the image quality.

4. Storage

   Once the image is processed and compressed, it's stored as a digital file in your smartphone's memory. The file format, typically JPEG or RAW, determines how the data is organized and stored:

   • JPEG: This is the most common format for the final image. It's a compressed and lossy format, suitable for sharing and viewing, but it does not retain all of the original data.
   • RAW: This format stores all the unprocessed sensor data, giving you a greater flexibility for post-processing; but it results in a larger file size.

5. Display and Sharing

   The processed image can now be displayed on your smartphone's screen. You can edit it, share it on social media, or send it to friends and family. The image is displayed as a grid of pixels, with each pixel's color and brightness contributing to the overall picture.

In essence, your smartphone's camera system combines advanced optics, sensor technology, and image processing algorithms to capture and transform the photons from the world around you into the digital images ready to be cherished and shared. It's a beautiful blend of science and artistry!

Dual Cameras in Smartphones

Dual cameras in smartphones are like having a dynamic duo of lenses, each with its own superpower. They work in tandem to capture photos and videos, offering unique advantages over single cameras.

Dual cameras in the smartphones offer versatility and creative potential, making them a popular choice for photography enthusiasts. They enhance zoom capabilities, enable captivating portrait effects, and open up new horizons for wide-angle shots. However, in the light of the cons listed above, it's a matter of weighing the pros and cons to determine if the dual cameras align with your photography needs.

Multiple Cameras in Smartphones

As in case of the dual cameras that we described in the above section, the multiple cameras or lenses on the back of a phone serve various purposes, enhancing the phone's photography and videography capabilities. Each camera or lens has a specific function, and the collective presence allows for a more versatile and creative photography experience. Here are some common purposes for multiple cameras or lenses on the smartphones:

• Primary Camera: This is the main camera that captures the standard photos. It is designed for everyday photography and performs well in various lighting conditions. The primary camera is the workhorse of the smartphone photography.
• Wide-Angle Camera: A wide-angle lens offers a broader field of view compared to the primary camera. It's perfect for capturing landscapes, group photos, and scenes where you want to include more in the frame without physically stepping back.
• Telephoto Camera: The telephoto lens allows for optical zoom, which maintains the image quality when zooming in on the distant subjects. This is in contrast to digital zoom, which simply enlarges and crops the image, often resulting in a loss of quality. Telephoto lenses are great for capturing details from a distance.

  (Related: Read about periscope telephoto lens.)

• Ultra-Wide-Angle Camera: Ultra-wide-angle lenses go even further than the standard wide-angle lenses, capturing an exceptionally wide view. They're excellent for dramatic, sweeping landscape shots, or for artistic perspectives where distortion can be used creatively.
• Macro Camera: A macro lens is designed for extreme close-up photography, allowing you to capture the intricate details of small subjects like flowers, insects, or even everyday objects. It provides a different perspective on the world around you.
• Depth Sensor: Some smartphones include a depth sensor, which is not used for taking photos on its own, but works in conjunction with the other cameras to measure the depth of the objects in the scene. This information is useful for creating portrait effects with blurred backgrounds (bokeh), and for the AR (Augmented Reality) applications.
• Monochrome Camera: Monochrome cameras capture black-and-white images. While not as common, they can produce stunning high-contrast photos with rich textures and details. Some phones use monochrome sensors to enhance low-light performance.
• Time-of-Flight (ToF) Camera: ToF cameras use infrared light to measure the distances between the camera and the objects in the scene with high precision. They're often used for 3D mapping, AR, and improved portrait effects.

The presence of multiple cameras on the back of a phone allows you to choose the best lens for a particular scenario, offering versatility and creative options for capturing photos and videos. Whether you're looking to zoom in on a distant subject, capture a breathtaking panorama, or get up close and personal with a macro shot, these cameras collectively provide a wide range of possibilities for smartphone photography and videography.

Frequently Asked Questions (FAQs)

• What is the best smartphone image stabilization?

  The gimbal stabilization will be the best, barring which (as it is rarely in-built), the HIS (Hybrid Image Stabilization) - which is a combination of the OIS (Optical Image Stabilization) and the EIS (Electronic Image Stabilization) - will be the way to go.

• How does it work: Optical Image Stabilization (smartphone)?

  The Optical Image Stabilization involves the physical mechanisms (such as tiny motors) inside the camera lens or the sensor that compensate for (counteract) the small movements of the shaky hands in real-time, and stabilize the image by changing the path of the light that reaches the sensor.

• How do smartphone cameras autofocus?

  The smartphone cameras employ different technologies to autofocus, such as:

  • Contrast Detect Autofocus: Analyzes the contrast in the scene and sets the focus where the contrast is at its peak (or at a set threshold amount).
  • Laser Autofocus: Shoots a laser beam at the subject and measures the time it takes to bounce back, thereby getting its distance. The camera then adjusts its components to achieve a sharp focus at that distance.
  • Phase Detect Autofocus (PDAF): Splits the incoming light into two separate beams, comparing them to determine if they're perfectly aligned. If not, the camera knows how much adjustment is needed to bring them together.
  • Dual-Pixel Autofocus: Works like PDAF but splits every pixel on the image sensor into two mini-pixels, by including two photodiodes with each pixel. This increases the number of focus points, making it possible to catch very subtle phase differences.
  • Quad-Pixel Autofocus: Splits every pixel on the image sensor into four mini-pixels, so that it can detect the phase change in all four directions.

• What is the purpose of dual cameras on the rear of a smartphone? What advantage are dual cameras on a smartphone?

  Dual cameras make your phone more versatile in terms of the kinds of photos and videos you can shoot by switching between standard, wide-angle, and zoomed-in shots.

  If the secondary camera is a telephoto lens, it enables optical zoom, which is better than digital zoom in terms of preserving the image quality.

  Dual cameras can create beautiful bokeh (background blur) and portrait effects.

  Some dual-camera setups use the secondary camera to capture additional light data, improving low-light performance and reducing noise in the photos.

• How does a smartphone camera work?

  A smartphone camera first captures the image, which involves opening the aperture, allowing the light to hit the sensor, and the pixels on the sensor converting the received photons into the electrical signals.

  The smartphone's image processor converts the electrical signals into digital data, including the colors, white balance, and other enhancements such as sharpening, noise reduction, and contrast adjustments, to improve the image's overall quality.

  The image data can then be saved as such (uncompressed, as RAW data), or it can be saved in a compressed image format (such as JPEG).

  The RAW data is good for manual editing; the JPEG image is good for sharing with others and for storage.