Camera sensor sizes explained
Updated 2026-10-17 · 8 min read
Sensor size shapes a camera system more than most specs: it affects how big the lenses are, how easily you can blur a background and how clean your pictures look in dim light. It does not decide everything, though, and a bigger sensor is not automatically the right choice.
The formats, largest to smallest
Medium format
In digital cameras, "medium format" usually means a sensor of about 44 × 33 mm. Fujifilm's GFX cameras and Hasselblad's X and 907X bodies use this size. Some high-end digital backs, such as Phase One's IQ4 150MP, use larger sensors of about 53–54 × 40 mm.
Both are smaller than medium-format film. The smallest common medium-format film frame, 6 × 4.5, measures about 56 × 41.5 mm. The 44 × 33 mm sensor has about 1.7 times the area of full frame and a squarer 4:3 shape. Bodies and lenses are usually bigger and dearer, and there are fewer lenses to choose from than for full frame.
Full frame
Full frame is about 36 × 24 mm, the size of a 35mm film frame, in a 3:2 shape. It is the reference point for crop factors and "equivalent" focal lengths. Canon, Nikon, Sony, Panasonic, Leica and Sigma all make full-frame cameras.
APS-C
APS-C takes its name from a 1990s film format. Most APS-C sensors are about 23.5 × 15.6 mm, with a crop factor of about 1.5. Fujifilm, Nikon, Sony and Pentax use this size. Canon's APS-C sensors are a little smaller, at about 22.3 × 14.9 mm, giving a crop factor of 1.6.
Both are 3:2. Full frame has about 2.4 times the area of the common size, and about 2.6 times Canon's. In video, the Super 35 cine format is roughly the same size.
Micro Four Thirds
Micro Four Thirds sensors have an imaging area of 17.3 × 13.0 mm, in a 4:3 shape, with a crop factor of 2. Olympus and Panasonic launched it in 2008 as a shared standard. That means lenses from OM System (formerly Olympus), Panasonic and others mount on any Micro Four Thirds body. Full frame has about 3.8 times its area.
1-inch type and smaller
A "1-inch" sensor is about 13.2 × 8.8 mm. Its diagonal is about 16 mm, well under an inch. The names come from television camera tubes. A tube's quoted size was its outside diameter, and the diagonal of its usable image area was only about two-thirds of that.
Smaller sizes follow the same convention. A 1/1.7-inch sensor is about 7.6 × 5.7 mm, and a 1/2.3-inch sensor about 6.2 × 4.6 mm. You'll find 1-inch sensors in pocket compacts such as Sony's RX100 series and Canon's PowerShot G7 X Mark III. The smaller types turn up in superzoom compacts, action cameras and phones.
The formats side by side
The last two columns show what you would need on each format to match a 50mm lens at f/2.8 on full frame. Figures are rounded and assume the typical size shown.
| Format | Typical size (mm) | Area (mm²) | Crop factor | Same view as 50mm on full frame | Same depth of field as f/2.8 on full frame |
|---|---|---|---|---|---|
| Large medium format | 53.4 × 40.0 | 2,136 | 0.65 | 77mm | f/4.3 |
| Medium format | 43.8 × 32.9 | 1,441 | 0.79 | 63mm | f/3.5 |
| Full frame | 36 × 24 | 864 | 1.0 | 50mm | f/2.8 |
| APS-C | 23.5 × 15.6 | 367 | 1.5 | 33mm | f/1.8 |
| APS-C (Canon) | 22.3 × 14.9 | 332 | 1.6 | 31mm | f/1.7 |
| Micro Four Thirds | 17.3 × 13.0 | 225 | 2.0 | 25mm | f/1.4 |
| 1-inch type | 13.2 × 8.8 | 116 | 2.7 | 18mm | f/1.0 |
| 1/1.7-inch type | 7.6 × 5.7 | 43 | 4.6 | 11mm | f/0.6 |
| 1/2.3-inch type | 6.17 × 4.55 | 28 | 5.6 | 9mm | f/0.5 |
Exact sizes vary a little between models, so check the spec sheet for a particular camera on its page under cameras.
What sensor size changes
Field of view and crop factor
Crop factor is the full-frame diagonal (about 43.3 mm) divided by a sensor's diagonal. Multiply a lens's focal length by the crop factor to find the full-frame focal length that gives the same field of view. A 23mm lens on a 1.5× APS-C camera frames roughly like a 35mm lens on full frame.
The lens itself has not changed. A smaller sensor simply records a smaller part of the image the lens projects. Micro Four Thirds and 44 × 33 mm medium format are 4:3 rather than 3:2, so the crop factor is a close guide rather than an exact match for width and height.
Depth of field
For the same framing, subject distance and f-number, a larger sensor gives shallower depth of field. To compare, multiply the f-number by the crop factor. A Micro Four Thirds lens at f/1.4 gives roughly the depth of field of f/2.8 on full frame.
Neither is better in itself. Shallow depth of field helps isolate a portrait subject. Deeper depth of field helps with landscapes, macro, group shots and video, where keeping things in focus is the hard part. The table shows why small-sensor cameras rarely blur backgrounds much: matching full frame at f/2.8 would take a lens far brighter than they come with.
Low-light noise
The same f-number, shutter speed and ISO give the same brightness on any sensor. But a larger sensor collects more light in total, simply because it has more area. When you view the images at the same size, more light means less visible noise.
The area ratio gives the theoretical gap at the same settings:
- Full frame vs APS-C: a little over one stop.
- Full frame vs Micro Four Thirds: about two stops.
- Full frame vs 1-inch type: nearly three stops.
- 44 × 33 mm medium format vs full frame: under one stop.
Real cameras don't follow these figures exactly. Sensor generation and processing can narrow or widen the gap, so compare sample images viewed at the same size. A brighter lens closes the gap: f/1.4 on Micro Four Thirds collects about the same total light as f/2.8 on full frame at the same shutter speed, and gives about the same depth of field. Stabilisation lets you use slower shutter speeds with still subjects, but it doesn't help with moving ones.
Lens size, weight and price
Smaller formats need shorter focal lengths for the same view. That matters most with telephotos. A 300mm lens on Micro Four Thirds frames like a 600mm on full frame. The M.Zuiko 300mm f/4 weighs about 1.3 kg, while Sony's full-frame 600mm f/4 weighs about 3 kg.
The advantage shrinks with bright lenses meant for shallow depth of field, because a small-format lens has to be faster to give the same look. As a rule, lenses for bigger formats are larger and dearer for a given view and brightness. Browse lenses by mount to see what each system offers.
Body size depends more on design than on format. For example, the Micro Four Thirds Panasonic Lumix G9 II weighs 658 g and the full-frame Canon EOS R8 461 g, both with battery.
Reach and diffraction
At the same pixel count, a smaller sensor packs its pixels more densely. With the same lens, a distant bird therefore covers more pixels. That helps wildlife and sports photographers who can't get closer.
The flip side is enlargement. A small sensor's image is enlarged more to reach a given print or screen size, so diffraction softening appears at a lower f-number than on a larger format.
What sensor size does not change
- Exposure. f/4 at 1/250 s and ISO 400 gives the same brightness on every format.
- The lens's focal length. A 50mm lens is a 50mm lens on any body. A smaller sensor crops the view; it doesn't magnify anything.
- Perspective. How near and far objects relate in size depends on where you stand, not on the sensor. Two formats framing the same scene from the same spot give the same perspective.
- Resolution. Megapixels are a separate choice. The APS-C Fujifilm X-T5 has 40.2 megapixels, and the full-frame Sony a7S III has 12.1.
- Features and handling. Autofocus, video specs, stabilisation, weather sealing, the viewfinder and the grip all depend on the model, not the format.
- Dynamic range, reliably. Larger sensors often have more, but design and generation matter too. Compare specific models rather than assume.
How to choose
Start with what you shoot and how much you want to carry, then pick the smallest format that does the job well.
- Pocket camera for travel and everyday shots: a 1-inch-type compact has a larger sensor than most phones' main cameras, usually with an optical zoom, in a body that fits a jacket pocket. A few flagship phones now use a 1-inch-type sensor too.
- Wildlife and sport on a budget: APS-C and Micro Four Thirds give more reach from smaller, often cheaper telephotos. Micro Four Thirds often has the edge for compact long lenses.
- Low light, events and shallow-focus portraits: full frame makes these easier and has a wide choice of bright lenses.
- Landscape, studio and fine detail at a slow pace: medium format gives the most light-gathering area. You pay for it in size, price and a smaller lens range.
- Video: every format is used. Deeper depth of field on smaller sensors makes focusing easier for solo shooters, and full frame gives more background blur.
Choose the mount, not just the body
Lenses usually outlast bodies, so the mount matters as much as the sensor. Canon RF, Nikon Z and Sony E each cover both APS-C and full frame. APS-C bodies take full-frame lenses for the same mount, and full-frame bodies use APS-C lenses in a crop mode with fewer pixels. Fujifilm uses separate mounts for X (APS-C) and GFX (medium format). Micro Four Thirds is a single format. See mounts for what fits what.
Check prices where you live
The format is the same in every market, but prices aren't. The same body or lens can cost noticeably more or less in the US, UK, EU, Australia and Singapore, and bundles differ too. Check that a listing is an official local import: makers often offer only a local warranty, so a grey import may not be covered. Compare current offers on deals before you commit.
To build a shortlist, cameras filters by sensor size and the camera finder suggests models by use, size and budget. Then compare puts two models' specs side by side.