The zoom capabilities of smartphones have come a long way and with the announcement of the space zoom in the Galaxy S20 Ultra, it has hit another milestone. 100x zoom! Alright, folks! This is technically nothing new but rather an extension of the 50x zoom feature that the Huawei P30 Pro had. And Samsung has intentionally chosen not to talk about the quality of photographs that you will get with 100x zoom and also how you should have a robotically strong arm in order to capture such pictures! But anyway, it’s always fun to talk about the science that works behind all these technologies, so let’s explore how space zoom in Galaxy S20 Ultra works! Zoom in cameras are of two types: optical
and digital. Optical means through optics or achieving zoom by bending light. If you look at any scene through a single lens, it appears upside down. This is because those lengths which are thicker at the middle also called convex lenses, refract light that passes through them through a single point called ‘focus’. The distance from the center of this lens to the focus is called the focal length and due to the convergence of light at this focus, the projections happen upside down! To nullify these cameras use one more convex lens which reverses the upside-down projection. You know, the negative of a negative is positive, so we get a right-side-up image. Now, some lenses go above and beyond this and add multiple pairs of convex lenses but for the sake of simplicity let’s consider such a setup which is also called ‘bi-convex lens’. To achieve optical zoom, a concave lens or a lens which is thinner at the middle is added in between these convex lenses. This concave lens would also help in eliminating chromatic aberration and spherical aberration, which are beyond the scope of this video! Light from the object passes through the
first convex lens and based on the position of the concave lens, the extent of zoom is decided. This setup helps in zooming optically and since we are bending light itself, there is no loss in quality of the photograph. But then, this setup is very bulky and has moving parts there are lenses which do 100 X optical zoom or even beyond that, like the Canon Digisuper 100 lens that stands at 10 inches tall, weighs in at 52 pounds and cost more than $200,000! More space, more weight, and more cost: three of the things that are exactly not suitable for a smartphone right? So that’s why earlier smartphones used to have simple digital zoom. Digital zoom is basically cropping into an image just like you would do in Photoshop or pinch into zoom in a smartphone. This depends just on the resolution of the camera as the higher the resolution, the higher you can zoom in! This is because as you do digital zoom you’re just cutting into the pixels which produce a loss in quality. Often you are better off with cropping in your photograph rather than doing digital zoom as zooming in digitally introduces focus issues due to the shake in our hands. Now, coming to phones like the Galaxy S20 Ultra, which uses the much-hyped space zoom or the Huawei P30 Pro, which had a 50x zoom, they use a combination of optical and digital zoom. These phones have a periscope lens, which has a prism to reflect light 90 degrees and have a lens arrangement along the width of the phone itself. This helps in keeping the moving parts within the phone itself and allows for optical zoom. But since the lens are very tightly packed, the optical zoom possible is only 4x. Samsung also claims that the space zoom can go up to 10x without noticing any drop in image quality with their
patented technology called ‘hybrid optic zoom’. Beyond that, it’s digital zoom. But there is a catch! There are two things that the Galaxy S20 Ultra does in order to achieve the 100x zoom. Those two things are high-resolution camera sensors and the power of on-the-fly image processing. To put it simply, after you pass the 10x threshold the phone will rely heavily upon digital methods to maximize the potential of the telephoto camera and by cropping sharpening and otherwise attempting to improve the result on the fly. But since algorithms can only go so far, the Galaxy S20 Ultra will also pull in data from the 108 MP sensor of its main camera then the processor delivers the final result by combining the image data from the telephoto camera. Having access to more image data from both sensors and combining it is what allows the S20 Ultra to achieve space zoom. But for capturing good pictures, you need to keep the phone super steady like on a tripod or you need to have a robotic arm! Arnold Schwarzenegger: “Now listen to me very carefully!” This is because at that level of zoom even
micro handshakes can produce significant disturbances in focus and also confuses the software about what to optimize! Either way, this can be considered a significant jump in the zoom technology of smartphone cameras. If you want to check out the hands-on review of the much-hyped space zoom in the Galaxy S20 Ultra, subscribe to my channel so that you can be notified once I upload it! Until then this is Param signing off wishing you absolutely nothing but the best of success!