It’s not unusual to see professional photographers with multiple camera bodies, each mounted with a prime lens. Prime lenses typically let in more light for faster action and better low-light photography, and have less distortion than many zoom lenses do. When you are dealing with the tiny sensors that are used on smartphones, you need as much light as possible, and you want a lens design that takes a minimum amount of space to keep the phone thin. So rather than have a zoom lens on a smartphone, really the best solution would be to have multiple cameras, each with their own unique prime lens. A professional will typically bring three focal lengths along, maybe a normal, a wide, and a telephoto. Samsung gives you three cameras on the back with exactly the three lenses you need.
The wider a lens is, the more area is in focus. The ultra-wide lens on the back of the S10 and S10+ is so wide that practically everything is always in focus, so no auto-focus is even needed. That lens is just always ready to shoot.
The telephoto lens uses phase-detect to focus, which is something that up until recently was only on the most expensive cameras. Most smartphones use contrast-detect focus. Imagine you are using an old manual focus lens either on a camera or a pair of binoculars. How do you focus? let's say you are looking at a bird. At first the bird is out of focus because the binoculars are focused to near, or in front of the bird, so you focus further right past the bird, now you are focused behind the bird. You slightly bring it back toward you and bingo, the bird is finally in focus. You had to hunt back and forth a little to get it, but in the end, it worked. Contrast detect works similar to this. The camera hunts back and forth until the contrast on the subject is strongest. The drawbacks of contrast-detect auto-focus is that it is a little slow and works poorly in low light, also, it has a problem with moving objects. Phase detect works radically different. The camera figures out where the subject is even it the subject is in motion, and just nails focus almost instantly the first time with no hunting back and forth, and it needs very little light to figure this out. How does it work? Well, when a subject is out of focus, the pixel sees two images, and one image might be closer to being in focus than the other. The camera can calculate how much it needs to focus the lens so that the two images converge. This is similar to how a golf rangefinder uses two images to triangulate distances on a green. This is a big deal and on the S10+ works flawlessly.
The normal lens takes the concept of phase detect a step further. This camera has what is called dual-pixel auto focus. Every single pixel on the sensor also has a phase-detect photodiode for incredibly fast focusing. This screams premium. It does everything the telephoto camera does, only faster. This is the camera you will likely use the most, and it works the fastest.
So three cameras, each with a unique method of focusing and each perfect for the intended application. These are indications of a well-engineered product.
That leaves two more cameras, and both are on the front. That’s a story for another time…
Disclaimer: The Product Ambassadors are Sprint employees from many different parts of the company that love technology. They volunteer to test out all sorts of Sprint devices and offer opinions freely to the Community. Each Product Ambassador shares their own opinions of these devices, therefore the information in this post does not necessarily reflect the opinions of Sprint. The PA's do not represent the company in an official way, and should not be expected to respond to Community members in an official capacity. #sprintemployee