Samsung is considering adding a rotating DSLR-like mirror to its smartphone cameras, based on a patent published by the World Intellectual Property Organization and reviewed by Android Headlines. Traditionally, a mirror inside of a camera serves the purpose of allowing light to be absorbed by a sensor and providing a real-time, extremely accurate representation of the final shot via a viewfinder up until the very last moment. Samsung's design shows the mirror as being able to rotate both horizontally and vertically, opening up the scope of what it might be used for well beyond light absorption.
A wide variety of use cases have been provided by Samsung and the most impactful may be the company's hint that a mirror might be used to squeeze a dual-camera array under one lens.
The mirror would essentially act to redirect light between two sensors for a single photo. For example, the mirror could rotate quickly in a single snap to send image data to both the RGB color and monochrome sensors typically found in a smartphone with a dual-camera. That would allow both sensors to share a lens and other components, ultimately reducing the space by comparison to a traditional dual-sensor camera.
Way more than just a light absorber
Aside from allowing two sensors under a single lens, Samsung's patent points to its use in at least two other interesting ways. The first of those is as an active part of the camera's anti-shake or subject tracking system. The mirror could, in effect, be rotated in tiny variances to smoothly follow and center the subject to offset hand-shake. It would essentially act as a built-in gimble without the need to include other image stabilization components.
Based on the movement of the subject, including speed and direction, the mirror could also help straighten images and track movement more cleanly, capturing a wider field of view and actively stitching frames together in photo modes. That could enhance panoramic camera modes or even enable minor improvements to subject tracking in video shooting modes.
The underlying software would be used to augment the user's view of the capture area to match the current capture mode and at least one of the patent images suggests users could preview more than one capture mode at once. For instance, the UI might show the user both a wide angle and cropped standard view side-by-side with options for capturing either. The same concept could be used to allow features already available in Samsung devices, such as the ability to snap a still photo while simultaneously recording video.
The feasibility of it all
Although Samsung isn't widely-heralded as a premier DSLR camera manufacturer, it is already considered among the best in terms of smartphone camera hardware. Its Galaxy Note 9 phablet flagship doesn't rank as the best but is right near the top right now, just below Huawei's P20 Pro and on par with HTC's U12 Plus, according to several established benchmarks such as French DxOMark Image Labs.
That doesn't necessarily make its idea for including a rotating mirror in a future smartphone any more viable than if another manufacturer were to consider it.
There are several reasons the concept may never make it to a real-world implementation but the scale of the hardware is probably the most prominent reason the invention may not be feasible. Although the invention does appear to reduce space requirements, it may simply be too small to offer the same improvements seen when large DSLR lenses are coupled with mirrors.
Issues with durability could arise as a result of the size of the hardware components involved too, given how finicky and precise mirrors need to be to work properly in a camera. Moving parts tend to add to the overall complexity and reduce durability, to begin with. Smartphones are expected to be thrown around, dropped, and shoved in pockets or handbags while enduring the rigors that entails.
The pieces holding the mirror and enabling its rotation would be minuscule even by the standards set by the most compact DSLR and those, generally speaking, already aren't most high-endurance gadgets.
Samsung may very well have a way around those problems but another issue could present itself in terms of cost as a result of that. Since the company's devices are already among the most expensive on the market, that could render the invention effectively pointless or unreasonable in the near term.