The sensor is the part of the camera that records the image. Its size affects low-light quality, background blur, the size of your lenses and the price.
| Format | Size | Crop factor | Brands |
|---|---|---|---|
| Medium format | 44 × 33mm | 0.79× | Fujifilm GFX, Hasselblad |
| Full frame | 36 × 24mm | 1× | Sony, Canon, Nikon, Panasonic, Leica |
| APS-C | about 23.5 × 15.6mm | 1.5× (Canon 1.6×) | Fujifilm, Sony, Canon, Nikon, Pentax |
| Micro Four Thirds | 17.3 × 13mm | 2× | OM System, Panasonic |
What crop factor means
Multiply a lens's focal length by the crop factor to see how it frames compared with full frame. A 50mm lens on APS-C frames like a 75mm lens on full frame; on Micro Four Thirds, like 100mm. That's why smaller sensors are popular for wildlife: the same lens gives more apparent reach.
Low light and background blur
With the same technology, a full-frame sensor collects about one stop more light in total than APS-C and about two stops more than Micro Four Thirds, so it's cleaner at high ISO. It also gives shallower depth of field at the same framing and aperture: f/2.8 on Micro Four Thirds blurs the background roughly like f/5.6 on full frame.
So which should you choose?
- Full frame for low light, portraits, weddings and the widest lens choice.
- APS-C for the best balance of size, price and quality, and extra reach.
- Micro Four Thirds for the smallest telephoto kits, travel and video.
- Medium format for maximum detail in landscapes, studio and commercial work.