# Designing a camera screen you can use with one hand

> Ingredient Scanner is used in supermarket aisles, usually while holding a basket. That changed where every button lives.

- Author: Tina, Team Lead · Mobile & Web
- Published: 2026-07-14
- Canonical: https://www.nexateam.dev/blog/one-handed-camera-screens
- About: [Ingredient Scanner](https://www.nexateam.dev/work/ingredient-scanner.md)

Our first version of Ingredient Scanner looked like most camera apps: close top left, flash top right, shutter at the bottom. It tested fine at a desk. In a supermarket, with a basket in the other hand, people struggled to reach anything above the middle of the screen. This is a field report on what we saw and what we changed.

## The study

Where

Ordinary supermarket aisles, at normal shopping times. No lab, no desk.

Who

Us first, then friends who had never seen the app, given no instructions.

Task

Walk an aisle, pick up a product, scan the label, decide whether to keep it.

What we watched

Grip, thumb movement, and every moment someone paused or shifted the phone.

## What we saw

01

#### Phones held low

Close to the body, one hand on a basket or trolley the whole time.

02

#### Top corners unreachable

People stretched for close and flash, gave up, and changed grip.

03

#### Nobody complained

They just slowed down. Friction showed up as hesitation, not feedback.

04

#### Results screen broke the rhythm

A new screen meant reaching up for back before every next product.

> Test where the app will be used, not where it was built.

## Everything moves down

We moved every control into the bottom third of the screen, inside the area a thumb reaches comfortably. Close became a swipe down that works anywhere on screen. Flash moved next to the shutter.

Close Flash Shutter

Swipe ↓ to close Flash Manual Shutter

Same screen, controls moved into the shaded area a thumb reaches while the other hand holds a basket.

## Results without leaving the camera

A successful scan used to open a new results screen with a back button in the corner. Now the result slides up over the camera view. Swipe it down and the next scan is ready.

1.  **Scan label**Shutter at the bottom
2.  **Result slides up**Over the camera, no new screen
3.  **Swipe down**Dismiss from anywhere
4.  **Next product**Camera is already open

The scan loop. The thumb stays in the bottom third the whole time.

## Fewer words on the result

The first result card listed every ingredient on the label. It was complete, and almost nobody read it in the shop. Now the card leads with a short verdict, shows the two or three ingredients that matter for the user's own preferences, and keeps the full list one tap away for later.

## Design principles we kept

1.  #### Reach before looks
    
    If a control is out of thumb reach, it does not matter how it looks.
    
2.  #### Stay in the loop
    
    Every action should leave the user ready for the next scan.
    
3.  #### Admit bad photos
    
    When a label is blurry, ask for another shot instead of returning a confident answer built on a bad image.