What is periscope telephoto and optical zoom?
Periscope telephoto is a camera lens design that allows high optical zoom without a protruding lens, while optical zoom is real magnification without losing image quality.
A periscope telephoto is a camera lens designed inside the phone so that light is reflected at a 90-degree angle using a mirror or prism, allowing a longer lens without sticking out from the phone body. This type of lens provides high optical zoom, such as 5x or 10x, compared to traditional telephoto lenses that usually offer 2x or 3x. Optical zoom, on the other hand, is the magnification done physically by the lens, not just cropping and enlarging the image digitally.
In daily use, optical zoom means zoomed-in photos stay clear and detailed, whether you're shooting a sports event from the stands, a distant bird, or architectural details. Unlike digital zoom, which reduces quality and adds noise, optical zoom preserves image sharpness. Also, periscope telephoto allows for a slimmer phone design while providing strong zoom, making it useful for travel and outdoor photography.
When buying, look for the optical zoom number in the specs, such as 3x, 5x, or 10x. The higher the number, the greater the reach, but image quality may drop in low light. Also check for optical image stabilization (OIS) to reduce shake, especially at high zoom. Don't confuse optical zoom with digital zoom; the former keeps quality, the latter reduces it. Finally, note that periscope lenses are often in flagship phones, but some mid-range phones may offer them too.