3.1 Mobile Photography

This is a historical learning note and may contain outdated or incomplete understanding.

1. Phone Hardware Knowledge

1.1. Pixels

Pixel count determines the sampling dimensions that can be recorded, but “how many megapixels are enough” depends on output size, cropping needs, the lens, and algorithms. For everyday social sharing, there is usually no need to pursue the highest-pixel mode.

1.2. Sensor

Size matters.

1.3. Algorithms

The shallow-depth-of-field effect in phone portrait mode usually relies heavily on computational photography simulation, but the lens’s own focal length, aperture, focusing distance, and sensor size still produce real optical depth of field.

2. Phone Accessories

A selfie stick that can be used as a tripod.

3. Phone Camera Functions

3.1. Xiaomi Phone Shooting Modes

3.1.1. Normal Mode

3.1.1.1. Center

3.1.1.1.1. Focus

Autofocus is used by default. The phone automatically identifies objects that differ clearly from the environment and occupy a relatively large proportion of the frame as the focus area; this area becomes clearer than the surroundings.

You can also focus manually. There is a focus ring: tap where you want to focus.

Focus lock: if the phone moves, it will reacquire the focus point. At this time, long-press a point to lock the focus point.

3.1.1.1.2. Exposure Adjustment

By default, the phone automatically calculates a “correct” exposure according to the scene or the selected focus point.

You can also adjust it manually. Tap an area to use it as the exposure reference. After focusing, the circle has an exposure-adjustment bar that moves up and down: move it up to increase exposure and down to reduce exposure.

Exposure lock: as with focus, long-press a point to lock exposure compensation.

3.1.1.2. Left Side

3.1.1.2.1. HDR

A measure for dealing with high-contrast scenes. A high-contrast scene means that the difference between bright and dark areas is especially large; in other words, the resulting photo will either underexpose the shadows or overexpose the bright areas.

How is it balanced? Phone HDR/computational photography usually combines multiple frames with different exposures or processing results to preserve highlight and shadow detail. The number of frames is not fixed at three; implementations vary greatly across phones and algorithms.

3.1.1.2.2. AI

Automatically recognizes the scene and sets some shooting parameters according to algorithms.

3.1.1.2.3. Flash

Generally not used; it is too harsh.

3.1.1.2.4. Filters

Generally not used.

3.1.1.2.5. Grid and Level

Turn them on.

3.1.1.2.6. Burst Shooting

In Settings, configure long-pressing the shutter button to trigger burst shooting.

3.1.1.3. Right Side

3.1.1.3.1. Zoom

Pinch with two fingers to zoom in or out.
Use the slider.

Prefer the phone’s native focal-length buttons/magnifications (for example, 0.6×, 1×, 2×/3×, depending on the model). These positions are more likely to use the corresponding camera directly; however, modern phones also use multi-camera fusion and digital cropping, so the slider cannot simply be treated as “pure optical zoom.” Continuous pinch zoom usually includes digital cropping and may reduce image quality.

3.1.2. Portrait Mode

3.1.2.1. Aperture Adjustment

Background blur.

3.1.3. Pro Mode

3.1.3.1. Center

3.1.3.1.1. Exposure

In Pro mode, the focus ring and metering ring can be separated.

If one area is dark, but tapping it makes other bright areas overexposed, how should it be handled?

Adjust exposure manually.
1. In Normal mode, after focusing, the circle has an exposure-adjustment bar that moves up and down: move it up to increase exposure and down to reduce exposure.
2. In Pro mode, there is a dedicated EV control.

3.1.3.2. Left Side

3.1.3.2.1. RAW Format

RAW/DNG preserves as much original data from the sensor and computational pipeline as possible and provides greater adjustment latitude, making it more suitable for scenes that need fine post-processing. It is not “film”; it is a digital raw-data file.

3.1.3.2.2. Focus Peaking

Focus peaking uses colored outlines to mark high-contrast edges that may be in focus. The exact colors and display behavior depend on the phone/app; it is an aid for judgment, not absolute focus detection.

3.1.3.2.3. Exposure Feedback

The colors and meanings of exposure feedback/zebra stripes/highlight warnings depend on the specific phone and app and should follow the current interface instructions.

3.1.3.2.4. 48-Megapixel Mode

Whether to use the high-pixel mode depends on lighting, motion, storage, and cropping needs. Normal mode is usually more suitable for casual shooting; high-pixel mode may be useful in sufficient light when detail is needed.

3.1.3.2.5. Metering

There are three metering modes. Average metering is generally enough; if the subject is in the center, center-weighted metering can be selected.

3.1.3.3. Right Side

3.1.3.3.1. Zoom

Wide-angle lens and ultra-wide-angle lens.

3.1.3.3.2. Exposure Compensation

3.1.3.3.3. ISO

3.1.3.3.4. Shutter Speed

3.1.3.3.5. Manual Focus

Use it together with focus peaking on the left.

3.1.3.3.6. White Balance

3.2. Metering

Pro mode provides different metering modes.

3.3. Shooting Aspect Ratio

The full sensor output of most phone main cameras is close to 4:3, so 4:3 often preserves more of the original frame. Ratios such as 16:9 and full screen are often based on cropping, but the exact implementation still depends on the model.

4. Post-Processing

4.1. Snapseed

[Snapseed] Very Detailed Mobile Photo Editing Tutorial Series

5. References

Lesson 3: How Is a Photographer’s Eye Developed? - Bilibili

Xiaomi phone shooting-function tutorials:

Tripod self-shooting: