DxOMark says its autofocus benchmark includes a measurement of shooting time lag, which is important for measuring autofocus speed. In its examples, devices can capture quickly between 100 and 200 ms, while others show 500 to 1100 ms of lag. One example device has an average shooting time lag of only 18 ms, while another introduces a notable lag of 546 ms on average.

The paper states that the Samsung Galaxy S6 Edge requires 42 ms to move the lens one step, including image capturing and autofocus processing. It also describes real-time constraints for smartphone autofocus and computes timing in frame units of 33.33 ms.

These metrics include focusing speed, accuracy, power consumption and user experience. Experimental results on a prototype digital camera platform are presented to demonstrate the applicability of the proposed metrics. We show that focusing speed can be quantified in terms of the time taken by the auto-focus algorithm to reach acceptable focus from an out-of-focus starting point, typically measured in milliseconds, and that different technologies (contrast detection vs. phase detection, etc.) have significantly different speed characteristics.

Samsung’s support guidance on phone cameras says poor focus can be caused by a dirty lens, software issues, or the Tracking auto-focus setting. It advises cleaning the lens, updating software, disabling Tracking auto-focus, and resetting camera settings if the camera will not focus on the subject.

PDAF (phase detection auto focus) is a high-speed automatic focus technology.[6] Conventional contrast AF takes time because it needs to move the lens to detect the focus point with the highest contrast. In comparison, PDAF can focus quickly by detecting the phase to move the lens to the focus point immediately.[6] Because PDAF can quickly and accurately focus the lens for each frame it detects, it enables faster and more accurate auto focus (AF) than conventional AF.[6]

With Samsung’s Dual Pixel technology, every pixel on the sensor is used for phase detection, while simultaneously receiving color information, greatly improving both the speed and accuracy of autofocus compared to conventional systems.[4] When capturing a scene, the phases from each pair of photodiodes are compared to achieve autofocus in just milliseconds.[4] As a result, Dual Pixel Pro delivers fast and accurate autofocus even under difficult conditions, such as low-lighting or fast-moving subjects.[4]

The outcome of the research is a novel benchmarking method for mobile phone cameras which includes both quality and performance metrics. The benchmarking includes different image quality metrics, performance metrics and methods that are used to create a straightforward score for comparing cameras. Quality and speed metrics in different illumination environments: a) Spatial resolution and b) Focus time. Focus time is defined and measured as the time needed for the autofocus system to achieve acceptable focus from an initial defocused state, allowing direct comparison of focus acquisition speeds across devices.

A smartphone camera can use phase detection, laser ranging, or contrast-based autofocus. The discussion notes that some phones can achieve near-zero shutter lag with specialized focusing hardware, while contrast-based autofocus may take longer because it has to search for focus.

A YouTube review of “5 phones with ultrafast camera focus” discusses claimed marketing figures for phase detection autofocus (PDAF) systems in smartphones. The reviewer notes Samsung’s PDAF implementation: “it has been much refined since and has reached ultra fast 0.1 second focusing times in the new Galaxy Note 5 and S6 Edge Plus… as well as their smaller S6 and S6 Edge siblings,” and cites Sony’s claim that the Xperia Z5 Compact “promises 0.03 seconds focusing times… still Sony warns that this is the minimum while the average focusing speeds will range from 0.1 to 0.4 seconds.” These examples show that some high‑end phones advertise best‑case AF times around 30–100 ms, while typical average focus times can be 100–400 ms, indicating performance targets rather than a strict industry requirement.

If you’re a typical user, you don’t need to overthink this: any 2024–2025 phone with phase-detection autofocus (PDAF) + dual-pixel or all-pixel sensors delivers consistent, near-instant focus in most real-life scenarios. In practice, tap-to-focus during recording should snap within ≤0.3s. Lag or hunting indicates weak tuning—even with high-end hardware. Delay >0.5s signals under-tuned firmware. For everyday moments, phones with PDAF or all-pixel AF provide reliably fast focus acquisition, while contrast-detection-only systems tend to be visibly slower to lock focus.

Phase detection auto focus splits the image into two 'copies', then adjusts the lens elements until the two images 'merge', i.e. until they're in phase. Its main advantage is speed.[2] A contrast-detect auto-focus system will always "hunt" for proper focus… A PDAF system will move smoothly from the starting position to the in-focus position.[2] Some newer smartphones have phase detection on the sensor as well. PDAF allows cameras to focus more quickly.[2]

A Google Pixel support thread describes the main camera initially focusing on very close objects and only refocusing on distant subjects after a noticeable delay of 0.5 to 3 seconds. This shows that some smartphone autofocus behavior can be much slower than 100 ms in real-world use.

The forum post says that tapping to focus works almost instantly, but autofocus problems occur mostly in lower light situations. This indicates that perceived focus speed varies by lighting and use case.

Phase Detection Autofocus is a high-speed focusing method that works by splitting incoming light into two images and comparing them to determine how the lens should move… By measuring the difference between the two images, or the “phase difference,” the camera can focus extremely quickly and accurately.[3] Unlike contrast-based autofocus, which moves the lens back and forth to find sharpness, PDAF instantly calculates where the lens should go.[3] In smartphones, it’s often implemented as Dual Pixel or All-Pixel Autofocus, helping deliver fast, smooth focus for photos and videos.[3]

The two main technologies used in cameras to focus are Phase-Detection autofocus (PDAF) and Contrast-Detection autofocus (CDAF). PDAF does give faster autofocus and low light performance. CDAF works by comparing the contrast between pixels on the point you want to focus on, moving the lens so that it sweeps across its range of focus, stopping and refining the focus when contrast is highest. Because CDAF has to iteratively search, it is generally slower to lock focus than PDAF, which can directly estimate the required lens movement, leading to significantly shorter focus acquisition times.

On this page, you can find Camera Scores for all smartphones we have tested at PhoneArena. Learn about our camera testing methodology and testing conditions. Our camera benchmark includes measures of speed such as shutter lag and autofocus responsiveness, evaluating how quickly the camera can lock focus and capture a shot under different lighting conditions. Modern flagships released in 2024–2026 typically show very short focusing delays, with high-end devices effectively focusing in a fraction of a second in our tests.

The post argues that smartphone cameras are effectively fixed focal length systems and that autofocus or fixed focus is mainly about getting the subject in focus. It is an anecdotal discussion, but it reflects common smartphone-camera assumptions in photogrammetry use.

Excellent camera performance, stills and videos, impressive telephoto cam. In our camera tests we consider not only image quality but also speed parameters such as shutter response and autofocus acquisition time. The best camera phones of 2026 have near-instant autofocus in good light and maintain fast focus lock in lower light, though in some challenging scenarios focus times can extend to several tenths of a second.

Phase Detection (the "Fast Planner"): This method is found in higher-end phones (often called "Focus Pixels" or "Dual Pixel" AF). It splits the incoming light into two images and compares them, allowing the phone to quickly calculate how far and in what direction the lens needs to move.[9] Contrast Detection (the "Careful Checker"): This is common in many phones. The camera moves the lens back and forth, checking image sharpness until it finds the point of maximum contrast, which can be slower and may "hunt" before locking focus.[9] Hybrid systems can combine Phase Detection and Contrast Detection to get both speed and accuracy, improving overall autofocus performance on smartphones.[9]

This YouTube tutorial gives troubleshooting steps for Android phones that will not focus, including force-stopping the camera app, clearing cache, restarting, enabling macro mode, and resetting camera settings. It is practical user guidance rather than technical evidence about autofocus timing.

Contrast Detection AF looks for the point of highest edge contrast by moving the lens back and forth, which inherently takes more time and can lead to hunting, especially in low light.[8] Phase Detection AF instead measures phase differences and can drive the lens directly to the focus position, resulting in faster autofocus and better tracking of moving subjects.[8] Sony’s Hybrid AF system combines contrast detection and phase detection, using PDAF for speed and CDAF for fine-tuning to achieve reliable focus performance.[8]

Smartphone autofocus systems generally use either contrast detection, which is slower and involves hunting for maximum sharpness, or phase detection, which is faster because it can compute both the direction and amount of lens movement needed.[2][6] In modern smartphones with PDAF or Dual Pixel AF, focus lock can often be achieved in a few tens of milliseconds under good lighting, while older or purely contrast-based systems may take several hundred milliseconds and contribute to noticeable shutter lag.[1][5] Hybrid autofocus approaches combine PDAF for coarse, rapid positioning with CDAF for fine-tuning, balancing speed against accuracy across varied shooting conditions.[4][8]