Focal Length Explained With Galaxy Lenses, 13mm to 111mm

Focal length is a photographic term that’s easy to get a handle on. Essentially, focal length (expressed in millimetres) describes how much of a scene a particular lens will capture, or, put another way, how wide or narrow a lens’s field of view is. Lenses with a short focal length (say, 13mm) will capture a wide swath of a scene; lenses with longer focal lengths (say, 111mm) will capture a narrower swath of a scene, making subjects appear closer and bigger.

In the Samsung camera app, you won’t see focal lengths. Instead, you’ll see four zoom options on Ultra models, 0.6x, 1x, 3x and 5x, each corresponding to a different camera (and therefore, a different focal length). Below, we’ll demystify Samsung’s zoom options by breaking down the focal length associated with each, describing the types of images you’ll get with each lens and offering tips for figuring out which lens to reach for in different shooting scenarios.

What is focal length?

Technically, focal length is the distance between a lens’s optical centre and the sensor when it’s focused on something far away. The longer the focal length, the larger the image of the subject on the sensor, so less of it, and the area around it, fits in the frame. Hence long lenses magnify and short lenses are wide angle.

But what counts as short and long depends on the size of the sensor, and since phones use tiny sensors, phone manufacturers talk about the focal length in 35mm-equivalents, representing what focal length would produce an equivalent image on a camera with a sensor the size of 35mm film. The actual focal lengths involved are pretty short: according to the data Galaxy phones embed in images, the main camera on a Galaxy S25 Ultra has a 6.3mm lens and the 5x telephoto an 18.6mm one.

Galaxy lenses in millimetres

Peek under the hood, in a photo’s EXIF data, and you’ll notice slightly different numbers. A Galaxy writes the zoom step multiplied by 23 into its pictures, so images from the 3x camera show a focal length of 69mm and those from the 5x report 115mm, even though the lenses themselves are closer to 67mm and 111mm. The zoom buttons are rounded the same way: measured from the 1x camera, the 3x is closer to 2.8x and the 5x more like 4.7x. It won’t affect your pictures, but it explains why different websites list different focal lengths for the same Galaxy.

Focal length and perspective

The notion that wide-angle lenses distort and telephoto lenses flatten is prevalent. The truth is that it’s all down to distance. If you wanted to take a portrait with a 13mm ultra-wide-angle lens, you’d have to get very close to the subject in order to fill the frame with their face, and at such close quarters the nose is significantly closer to the camera than the ears, so will look disproportionately large. But if you stand a few metres away and use the 3x lens, the ears and nose are at almost the same distance from the camera, and the face looks more natural.

It’s the same with backgrounds. Shooting from afar with a long lens will make mountains and buildings loom impressively large behind your subject (this is often referred to as compression). Conversely, shooting from close by with a wide-angle lens will make backgrounds recede into the distance, and exaggerate the size of the nearest objects. Choose your focal length according to the foreground-background relationship you want, then move your feet to get the composition you want. Our perspective guide has further examples.

Which focal length to use for what

Optical zoom, sensor crops and digital zoom

Only the lenses themselves give true optical focal lengths; the steps in between are made by cropping the nearest camera’s picture. On recent Ultra models Samsung calls the 2x and 10x steps optical quality, because they crop the centre of the very high-resolution 1x and 5x cameras and still produce a sharp 12MP picture. Beyond 10x, Samsung uses a heavily processed digital zoom it calls Space Zoom. It goes all the way to 100x and can be useful in a pinch, say for a picture of the moon or a far-away sign, but image quality drops quickly as you zoom further. Our 100x zoom guide shows where it stops being useful.

If your phone doesn’t have a telephoto camera (Galaxy A phones for example), the 2x zoom level will just be a crop of the main camera’s image. This works okay in most situations with good lighting, but a true telephoto camera is better for portraits and pictures of things far away.

Focal length and camera shake

Hand movement is magnified the longer the focal length, so you need to compensate for that with a faster shutter speed. A good rule of thumb is to have a shutter speed that’s faster than 1 divided by the 35mm-equivalent focal length, so about 1/30s at 1x and about 1/125s at 5x. Image stabilisation will help, but leave some margin for error, especially if shooting with the telephotos in Pro mode. Or find something to lean the phone on. Our shutter speed guide covers moving subjects too.

Frequently asked questions