Sensor size is a physical measurement — the actual dimensions of the light-sensitive chip inside a camera — and it affects far more than most spec sheets let on. Two cameras with identical megapixel counts can behave completely differently depending on sensor size, because a larger sensor is gathering the same information across more physical area.
The Common Sensor Sizes
| Format | Approx. Size | Common In |
|---|---|---|
| Full-Frame | 36 × 24mm | High-end mirrorless and DSLR bodies, cinema cameras |
| Super 35 / APS-C | ~23 × 15mm | Most mirrorless cameras, cinema cameras, DSLRs |
| Micro Four Thirds | ~17.3 × 13mm | Panasonic and Olympus/OM System mirrorless systems |
| 1-inch | ~13.2 × 8.8mm | Compact cameras, drones, gimbal cameras like the Osmo Pocket line |
| Smartphone sensors | Typically 1/1.3″ or smaller | Phone cameras |
Low-Light Performance
A larger sensor, all else equal, gathers more light per pixel, which directly improves low-light performance and reduces visible noise at high ISO. This is the single biggest practical reason full-frame and Super 35 sensors remain the standard for professional video and photography work in mixed or low light — a smaller sensor has to work harder (higher gain, more noise) to reach the same brightness in the same conditions.
Depth of Field and Field of View
Sensor size changes how a given lens behaves, described by a “crop factor” relative to full-frame. A Super 35 sensor has roughly a 1.5x crop factor, meaning a 50mm lens on that sensor frames roughly like a 75mm lens would on full-frame. The same math affects depth of field: at an equivalent framing, a larger sensor produces shallower depth of field than a smaller one at the same aperture, which is why full-frame cameras are often associated with a more pronounced background blur.
Neither of these is strictly better — shallow depth of field suits some work and is a liability in other work, like documentary or run-and-gun shooting where more of the frame needs to stay in focus without constant refocusing.
Size, Weight, and Cost
Sensor size scales with everything around it. Larger sensors need larger, heavier, more expensive lenses to cover their image circle, and bodies built around them tend to be bigger. This is exactly why gimbal cameras, drones, and compact vlogging cameras use small 1-inch or smaller sensors — the whole system stays pocketable, at the cost of low-light performance and shallow depth of field control.
Matching Sensor Size to the Work
Full-frame and Super 35 remain the default for professional narrative, commercial, and documentary work because they balance low-light performance, lens selection, and depth of field control well. Micro Four Thirds trades some of that for a smaller, lighter system, popular in run-and-gun and travel work. 1-inch and smaller sensors prioritize portability above all else, appropriate for gimbal cameras and situations where size matters more than ultimate image quality.
Conclusion
Sensor size is a physical trade-off between low-light performance, depth of field control, and system size and weight — not a simple bigger-is-better spec. The right size depends on what a shoot actually needs: a documentary crew moving fast and light has different priorities than a narrative DP working with controlled lighting and a full grip package.