Fix the lighting before you buy a webcam
Most complaints about webcam quality are complaints about the room. A better sensor in bad light still looks bad, and the fix is usually free.
The usual sequence is: video calls look bad, so buy a better webcam, and the calls still look bad. The camera was rarely the problem.
Cameras do not create light. They record whatever reaches the sensor, and if what reaches the sensor is a dim room with a bright window behind you, no sensor resolves that into a good image. Understanding what the camera is fighting explains why an expensive one often changes so little.
What the camera is actually doing in a dim room
A camera has three ways to compensate for insufficient light, and each has a visible cost.
Open the aperture. Fixed on essentially every webcam. Not available.
Slow the shutter. Each frame gathers light for longer. Motion smears, and the frame rate drops — the stuttery, slightly-behind-the-audio look familiar from bad calls.
Raise the gain. Amplify the signal electronically. This amplifies sensor noise along with the image, producing the grainy, crawling texture that reads as “cheap webcam”, and then the noise reduction smooths it into a soft, waxy image with no fine detail.
A larger sensor collects more light per pixel and needs less of this compensation, which is the real difference between a good webcam and a poor one. But it is a difference in how much bad light the camera can tolerate, not an escape from it. Give a large sensor a dark room with a window behind the subject and you get a better-quality silhouette.
The three room problems, in order
A window or lamp behind you
The most common and the most damaging.
Cameras expose for the overall scene. With a bright window behind you, the average brightness is high, so the camera reduces exposure — and your face, which is not lit by that window, becomes a dark shape. Auto-exposure is not malfunctioning; it is doing exactly what it was designed to do with the scene it was given.
The fix costs nothing: turn ninety degrees so the window is to your side, or close the blinds and light yourself another way. Backlight is the one problem where no camera and no setting recovers the image.
Light only from directly overhead
A ceiling light above and slightly behind you casts your brow’s shadow into your eye sockets and your nose’s shadow down your face. It is the lighting of an interrogation scene, and it is the default in most rooms.
Overhead light also means very little of it reaches your face directly, so the camera is still working in dim conditions while the room looks perfectly bright to you. Eyes adapt; sensors do not.
Not enough light overall
Rooms that feel comfortable are frequently darker than a webcam wants. This is where the gain and shutter compromises above come from, and it is why the same camera looks fine at midday and poor at nine in the evening.
What good looks like
The target is soft light, in front of you, at roughly face height or slightly above.
In front so your face is lit rather than shadowed.
Roughly face height or a little above so shadows fall downward and slightly back, which is how faces are normally lit and therefore what looks unremarkable. Light from below is the torch-under-the-chin effect.
Soft, meaning from a large surface rather than a small bright point. A bare bulb produces hard-edged shadows and shiny highlights on skin. The same bulb through a diffuser, or bounced off a wall, produces gradual shadows that flatter.
Off to one side, around 30 to 45 degrees, rather than dead centre. Straight-on light is flat and featureless; angled light gives a face some dimension.
Doing it for nothing
Before buying anything:
Face a window. Daylight through a window is a large, soft source. Sitting so it falls on your face from the front or front-side is better than most lighting people buy.
Move your desk lamp. Point it at the wall in front of you rather than at your desk. The wall becomes a large soft source, which is exactly what you want.
Turn on more lights generally. Two dim sources beat one, because the second fills the shadows the first creates.
Put something bright in front of you. A wall, a white surface, anything that bounces light back at your face.
Doing all four costs nothing and gets most people to acceptable.
When to actually buy a light
If you take calls after dark, in a room without a usable window, or you need the same result every day regardless of weather, a dedicated light earns its place.
What matters:
Size, over almost everything. A larger emitting surface gives softer light. A small very bright panel is a hard source; a larger dimmer one is usually the better picture.
Adjustable brightness. Fixed-output lights are often too bright at close range, which produces harsh highlights and makes people squint.
Adjustable colour temperature, if you have other light in the room. Mixing warm lamplight with cool daylight-balanced LED gives skin an odd cast the camera cannot correct.
Positioning. A light you can get in front of your face at the right height. A light stuck behind the monitor is a light in the wrong place.
Where the camera comes back in
Once the light is right, the camera does start to matter, and this is the point to buy one.
Sensor size first — it is the specification that decides how the camera behaves in the light you actually have. Field of view second: wide angles fit more room into the frame and distort faces at close range, which is why some webcams make noses look larger. A narrower field is usually more flattering for one person at a desk.
But this is the last step, not the first. A good sensor in good light looks good; a good sensor in bad light looks bad; a modest sensor in good light looks better than the expensive one did in the dark.
The short version
Move relative to your window, put a lamp in front of you rather than above you, and turn on more lights than feel necessary. Then get on a call and look at yourself.
If it still looks bad, buy a light. Buy the camera after that.