Buying a Phone for Its Camera? How to Read the Specs and Test It

A camera listing is where brands show off hardest. “200MP” and a cluster of lenses won’t tell you how photos from a school function in a dim hall will turn out, or whether a clip filmed on a bumpy road stays watchable. This is how to choose a camera phone without being dazzled by the box.

In this article10 topics

1. Decode the camera listing first
2. The main camera: sensor size beats the megapixel badge
3. Zoom: which steps are truly optical
4. Extra cameras: useful or just padding?
5. Steady shots: OIS, EIS and the video line
6. Low light: processing decides more than hardware
7. Shooting RAW: is the extra storage worth it?
8. Try it yourself: a camera test plan
9. Camera spec questions, answered
10. Official sources used in this guide

Decode the camera listing first

Start with this cheat sheet; the sections below explain each line.

On the listing	What it usually is	What to check instead
Main camera: “200MP” or “50MP”	The sensor’s pixel count; by default it often saves binned, lower-resolution photos	Sensor size, and the resolution your photos really come out at
“Periscope telephoto”, “3x” or “5x optical zoom”	A dedicated telephoto camera	That camera’s sensor size, megapixels and OIS
“2x optical quality”	Made by the main sensor rather than a lens of its own	How sharp that one step looks
“Up to 30x” or higher	Digital or processed zoom past the optical step	Nice to have, not a buying reason
“2MP macro” or “2MP depth”	An extra camera with low resolution	Leave it out of your comparison
“4K/60fps”	The best video mode on offer	Which cameras support it, and whether it’s stabilised

The main camera: sensor size beats the megapixel badge

Megapixels and pixel binning

A megapixel figure is simply how many pixels sit on the sensor. In good light, more pixels can capture more detail, but squeezing more onto a sensor of the same size makes each pixel smaller. Samsung’s page for the 200MP ISOCELL HP2 sensor explains the knock-on effect: a smaller pixel takes in fewer electrons, so the HP2 merges neighbouring pixels when light drops.

That merging is pixel binning, and the HP2, Samsung says, can merge as many as 16 pixels into one. Four-pixel groups produce a 50MP image made of 1.2µm pixels; sixteen-pixel groups yield 12.5MP, with each pixel 2.4µm across, which Samsung says means cleaner low-light shots with less noise. The cost is resolution: a “200MP” phone usually saves a far smaller photo unless you switch to its full-resolution mode. Google makes the same point in a footnote on its Pixel tech specs page: the megapixel number refers to the sensor itself, and photos shot on default settings may be lower in resolution.

Sensor size: the fraction to look for

Physical sensor size matters more than pixel count. It’s written as an inch fraction, and in a size like 1/1.56-inch, the smaller the second number, the bigger the sensor. Google’s Pixel 11 Pro Fold spec sheet shows why every camera needs checking: the main camera gets a 1/1.56-inch sensor, the ultra-wide only 1/3.4-inch. Secondary cameras can have much smaller sensors, so they may struggle earlier as light fades.

Aperture: how wide the lens opens

The f-number (f/1.7, for example) describes how wide the lens opens to let light in. As Nikon’s explainer on aperture puts it, a smaller f-number means a bigger opening and more light. A wide opening also narrows the depth of field, so the background behind a nearby subject turns soft.

One phone can mix very different apertures, so check each camera separately. On the Pixel 11 Pro Fold, Google gives the main camera f/1.70 but the telephoto only f/3.1, meaning the zoom camera has far less light to work with. Sensor size still counts, though: a tiny sensor behind a bright lens won’t automatically outdo a bigger sensor with a slightly narrower aperture.

Zoom: which steps are truly optical

Samsung’s Galaxy S25 camera explainer draws the line clearly. Digital zoom crops into the image and enlarges it, which can lose detail; optical zoom magnifies with the lens itself, so the picture stays sharper. The only truly optical zoom level, then, is the one the telephoto was designed around.

Marketing labels blur that line. The same Samsung page keeps genuine optical zoom apart from its 2x “optical quality” setting, which it attributes to the main sensor. Google, in its Pixel 11 Pro Fold spec sheet, uses three different terms:

• “5x optical zoom”, which belongs to the telephoto camera;
• “optical quality” at 0.5x, 1x, 2x, 5x or 10x;
• “Super Zoom up to 30x”, which a footnote says doesn’t work with every camera, app or mode.

A genuine telephoto appears in the spec list as its own camera, with a separate megapixel figure, an “optical zoom” number and, ideally, OIS. Google’s 5x telephoto is listed exactly that way.

Extra cameras: useful or just padding?

Every camera on the back should earn its place. Ultra-wides earn theirs for group shots, buildings and cramped rooms; before you count one as a plus, check its megapixels and its sensor size, and confirm it can autofocus.

Autofocus also shapes close-ups. Google’s spec list gives the Pixel ultra-wide auto-focus and “Macro Focus”, which means that camera handles close-ups instead of a dedicated macro lens. Other phones add a separate macro or depth camera with low resolution, which inflates the lens count without doing much for everyday photos.

• A big main sensor backed by OIS
• If you zoom a lot, a telephoto that carries its own optical zoom figure
• An ultra-wide that can autofocus

• Macro or depth cameras with low resolution
• “Up to” zoom claims that no telephoto camera backs up

Steady shots: OIS, EIS and the video line

OIS physically shifts the lens or the sensor to cancel out hand shake, as Samsung’s explainer describes it. Android’s camera developer docs explain that because OIS relies on mechanical parts, it lets the camera expose for longer before shake blurs the image, so night photos benefit too. Not every device has it, the docs add.

EIS, the electronic kind, is done in software. Android describes it as warping each frame to even out motion between frames, and it may alter the crop region, which is why stronger electronic modes usually cut into the edges of the shot. Many phones combine the two; Google lists both optical and electronic stabilisation for the wide and telephoto cameras on the Pixel 11 Pro Fold.

• Confirm the mode you’ll use is stabilised. Android says a phone that supports video stabilisation won’t necessarily stabilise every combination of resolution and frame rate. Recording apps are only guaranteed it up to 1080p at 30fps. On Google’s sheet, for instance, its “Active” stabilisation is offered at 1080p only, with other modes for 4K.
• Find out which cameras record 4K/60. If it isn’t listed, film a short clip on every camera while testing and open each clip’s details afterwards.
• Check front-camera video too. If you post reels, vlog or make video calls, the selfie camera deserves the same attention as the main one. Google lists front video separately (on the Pixel 11 Pro Fold, 4K at 30 or 60fps); if a listing covers rear video only, ask.

Low light: processing decides more than hardware

Night modes shoot a burst of frames and blend them. Samsung says its Night mode combines several exposures, and Google’s help page on Night Sight tells you to keep still for a few seconds while the phone captures. On Pixels, Night Sight turns itself on when light is low in the Photo and Portrait modes, but not while the flash is enabled. For astrophotography, Google advises a tripod or a steady surface.

After the shutter, software takes over. It chooses how far to lift shadows, how hard to sharpen, which way to push skin tones and how to balance a face against a bright window. Phones with near-identical hardware can deliver very different pictures, and Samsung itself says low-light results depend on the light, the subject and how you shoot. That’s why your own test beats any spec.

Shooting RAW: is the extra storage worth it?

RAW files hold on to more of the sensor’s data, leaving room to correct exposure and colour afterwards. Android’s camera framework saves raw output as DNG. Google’s DngCreator documentation calls DNG a format that works across platforms and stores sensor data after only minimal pre-processing. Not every brand’s camera app offers RAW, so look in the Pro or Expert mode during your test.

Apple’s version is Apple ProRAW, available on the iPhone 12 Pro and newer Pro models with iOS 14.3 or later. Enable it under Settings → Camera → Formats and then tap the RAW button in the Camera app. Expect big files: Apple says a ProRAW file is 10 to 12 times bigger than a HEIF or JPEG one and uses the DNG format. Live Photos, Portrait mode and video can’t be combined with it. Editing in RAW means setting aside extra storage.

Try it yourself: a camera test plan

Run these on a shop’s demo phone or on your own handset in its first few days. Check the seller’s return and replacement terms beforehand, since time limits and conditions vary. Buying pre-owned? Do our second-hand phone checks too.

1. Daylight: photograph one scene with every camera and look at colour and sharpness side by side. If quality falls off sharply away from the main camera, that’s where the brand saved money.
2. Zoom: work through the zoom presets (0.5x, 1x, 2x, 5x or whatever the phone offers), then pinch-zoom slowly across the whole range. If colour or framing suddenly jumps, the phone has probably handed over to a different camera.
3. Contrast and motion: shoot someone in front of a bright window to check exposure, then a moving subject such as a running child, a pet or passing traffic to check shutter lag and motion blur.
4. Low light: after sunset or in a poorly lit room, take a no-flash shot while keeping still, then check faces and lettering for smudging.
5. Video: walk while filming 30 seconds in your normal setting (4K at 60fps, say), then again in the strongest stabilisation mode. Compare the shake, how much of the frame is lost and whether resolution fell.
6. Selfie: film yourself on the front camera under indoor tube lights and outside, then place a quick video call.
7. Files: open a photo’s info panel in the gallery to confirm its resolution, view a few samples full-size on a laptop, and see how much space one minute of 4K footage takes.
8. Faults: found a camera that refuses to focus, a mark on the glass or jittery footage from a camera advertised with OIS? File for a return or replacement before the window shuts, and hold on to your test shots as evidence.

Camera spec questions, answered

Why are my “200MP” photos far smaller than 200MP?

High-resolution sensors usually merge pixels and output smaller photos unless you pick the full-resolution mode; Samsung’s HP2 page shows its 200MP sensor producing 50MP or 12.5MP images this way. So a 200MP camera doesn’t automatically beat a 50MP camera. Look at sensor size, stabilisation and processing instead.

Is “2x optical quality” the same as a 2x telephoto?

No. Samsung attributes its 2x “optical quality” step to the main sensor; there’s no separate lens behind it. A genuine telephoto is listed as a camera of its own, with its own megapixel figure and an “optical zoom” rating like 3x or 5x. “Up to 30x” alone proves nothing.

Is OIS worth having if the phone already has EIS?

Yes. Because OIS is mechanical, it lets the phone use longer exposures before hand shake blurs the shot, so it helps stills as well as video. EIS is software and can crop into the frame. Look for both on the main camera, and if zooming is a habit, on the telephoto as well.

Is RAW worth switching on for everyday photos?

Only if you’ll edit them. RAW keeps more data but eats storage: Apple says a ProRAW file is 10 to 12 times bigger than a HEIF or JPEG one. If your photos mostly end up on WhatsApp or Instagram, stick with the normal photo mode.

Official sources used in this guide

• Samsung Semiconductor: the 200MP ISOCELL HP2 sensor and how it bins pixels
• Google Pixel Phone Help: hardware specifications for Pixel phones
• Google Pixel Camera Help: low-light photos with Night Sight
• Samsung UK buying guide: what the Galaxy S25 camera specs mean
• Nikon USA: aperture and f-numbers explained
• Android Developers: CaptureRequest reference, including stabilisation modes
• Android Developers: DngCreator, the class behind RAW (DNG) files
• Apple Support India: what Apple ProRAW is and how to use it