Screen with low reflection and a solid hinge

The iPhone Duo is Apple’s first foldable iPhone, which began sales on the 23rd of October. The most noticeable part of the product after a week of use was the 7.6-inch inner OLED screen that appears when unfolded. A nano-texture finish was applied, preventing strong light reflections even under bright lights, and when swiping a finger across the screen, it felt rougher than a standard glass screen.

In exchange for reduced reflection and glare, the screen's color reproduction was more muted than the outer display. Users who prefer the vivid and intense colors of a glossy OLED screen may notice the difference. The crease in the center of the screen was not immediately visible from the front at first, but it became more noticeable to the eye as time passed.

The hinge moved with an appropriate level of resistance, allowing the screen to be propped up at desired angles. It also felt stable when placed on a desk in a half-folded state. However, the device weighs 254g, which felt heavy compared to its size when folded, and it was cumbersome to hold the unfolded screen with one hand for long periods.

Mixed results on app optimization and camera usage

Not every app utilizes the larger screen to the same degree. While some apps, such as KakaoTalk and Netflix, operate tailored to the Duo environment, other apps display narrowly in the center of the screen, leaving empty space on the left and right. As it is early in the product's release, it appears that app utility will increase as app developers carry out optimizations.

The camera consists of a 48-megapixel main camera and an ultra-wide camera. There is no separate telephoto camera, so there are limitations to high-magnification shots, but features like checking the subject on the outer screen or folding the device halfway for a fixed-angle shot were convenient. These are instances where the form factor of the foldable phone is utilized for photography.

Touch ID, durability, and the burden of a high price

The biometric authentication method is an area that existing iPhone users will need to adapt to. Instead of Face ID, the Duo integrates a Touch ID fingerprint sensor into the side button. Authentication is possible whether the device is folded or unfolded, and the fingerprint recognition itself was stable, but users accustomed to Face ID might find the action of placing a finger on the side button every time they unlock the device to be cumbersome.