Why Can the iPhone 6s - XS Record 4K but Not Take 4K Photos?
The iPhone 6s through the iPhone XS possess a remarkable capability to record video in 4K resolution, yet they fall short in capturing still photos at the same resolution. This discrepancy arises from the distinct methodologies employed for processing and storing video versus still images.
Resolution Differences
The distinction between 4K video and high-resolution photos lies in their pixel counts. A 4K video has a resolution of 3840 x 2160 pixels, while a high-resolution photo typically boasts a far greater number. For instance, the iPhone 6s features a 12 MP camera, generating images with a resolution of 4032 x 3024 pixels. When capturing video, the camera can optimize data for continuous motion, enabling the device to record in 4K. However, still images necessitate an entirely different set of processing techniques focusing on detail and color accuracy.
Processing Requirements
The process involved in video recording involves capturing frames and compressing this data efficiently at a certain frame rate—usually 30 or 60 frames per second. The iPhone's hardware is specifically designed to handle this continuous and dynamic task. Conversely, capturing high-resolution still images demands different processing capabilities that prioritize detail and dynamic range, tailored for still photography rather than video.
Software and Features
The iPhone's camera software is tailored to support various video features like stabilization and HDR, which may not be as applicable to still photography. Apple emphasizes optimizing the photo-taking experience for quality, often at the expense of video format compatibility. This means the camera settings and resolutions may differ between video and still photography modes.
Understanding 4K in Photography
It's essential to note that 4K resolution translates to 8 megapixels in the context of photographs. A 4K resolution of 3840 x 2160 equates to a total of 8,294,400 pixels, which is indeed a high-resolution image. Many smartphones, including some older models like the iPhone 6s and 7, have cameras capable of producing resolutions higher than 4K. However, they often don't advertise these photos as "4K" because, as mentioned, the resolution does not precisely match the 3840 x 2160 standard. Instead, cameras are frequently measured by their megapixel count (MP).
For example, the LG V40 phone with a 12MP camera can produce a 4032 x 3024 image, which is even higher than 4K. However, they don't refer to it as "4K" because the resolution is slightly different. Modern high-end smartphones, such as the Samsung Galaxy S23 Ultra, feature 200MP cameras capable of producing ultra-high-resolution images exceeding even 8K. These cameras, however, default to lower resolutions to maintain camera speed and reduce storage space usage. Users can manually select ultra-high resolution settings if needed.
In summary, while the iPhone 6s through the iPhone XS can record 4K video, their still image capture prioritizes high resolution and quality. This explains the disparity in 4K capability between video and still images on these devices.