Canon EOS 5DSR and 5DS full frame photo cameras.

Digital cameras use a sensor that captures light to make a photo. The size of the sensor affects how your images look, so you’ll often see photographers and tutorials referring to crop sensor and full frame sensor cameras. Here’s how to know which you have—and understand the difference.

Full Frame vs. Crop Sensor

Before digital cameras came along, the most popular film for photography was 35mm format. It’s 36mm x 24mm (1.4 inches x 0.94 inches) in size.

Full frame cameras use a digital sensor that’s about the same size as 35mm-format film. This was convenient for transitioning between film and digital, as it kept things as similar as possible. Photographers could use the same lenses and, if they used the same settings, images would look much the same.

canon eos film
My 30-year-old 35mm film camera can still use modern lenses. Harry Guinness

However, full-frame sensors are pretty big and expensive. They’re much larger than what is necessary to take good digital photos, so most consumer cameras use a smaller, cheaper, “cropped” sensor. (For comparison, a full-frame sensor is around 30 times the size of the 1/2.55″ sensor in the iPhone 12.)

graphic showing size of APS C vs full frame
The relative sizes of 35mm (pink), APS-C Nikon (red), and APS-C Canon (green). Harry Guinness

For DSLRs and mirrorless cameras, the most common crop sensor size is APS-C, which is around 24mm x 16mm. The next size down, used in some mirrorless and compact cameras, is Micro 4/3, which is 17mm x 13mm.

You Probably Have a Crop Sensor Camera

If you have a consumer DSLR, like a Canon Rebel T8i, Nikon D3500, or any of their predecessors, you have a crop sensor camera. There just aren’t any entry-level full-frame cameras.

If you’ve acquired an older, second-hand DSLR—especially if it seems like a professional camera—it might be full-frame. Some of the most popular models of the last decade or so are:

  • Canon 5D, 5D Mk II, 5D Mk III, 5D Mk IV, 6D, and 6D Mk II.
  • Nikon D600, D610, D700, D750, D780, D800, D810, and D850.

If your camera isn’t on the list, the simplest way to double-check is to Google its make and model number. Unless it’s explicitly stated that it’s full-frame, it almost certainly uses a smaller sensor.

Note: There’s a tiny chance that the sensor is medium or large format, both of which are bigger than 35mm. If that’s the case, you’ve got a very expensive and sought-after bit of kit on your hands!

What Does It Matter Anyway?

Full frame and crop sensor cameras are a bit of a throwback. Sensor technology has come so far with smartphones that the size of the sensor has never been less relevant to the quality of the photos you can take. However, that isn’t to say that sensor size doesn’t affect things.

The most relevant, especially if you’re reading photography tutorials, is crop factor. Because of the way lenses work, a small sensor gets more magnification from the same focal length lens. If you put a 50mm lens on both a full frame and a crop sensor camera, you get a different field of view.

This one’s the full frame:

full frame 50mm photo
Canon 5D Mk III and 50mm f/1.8. Harry Guinness

This (seemingly zoomed-in) shot is from the crop sensor:

crop sensor 50mm photo
Canon 650D and 50mm f/1.8. Harry Guinness

The relationship between the focal length of the lens and the apparent, or full-frame equivalent focal length, is the crop factor. It’s normally between 1.5 and 1.6, so that 50mm lens on the crop camera is equivalent to an 80mm lens on a full frame camera.

Here’s a shot with an 85mm lens on a full frame camera for comparison:

full frame 85mm photo
Canon 5D Mk III and 85mm f/1.8. Harry Guinness

Read our full explanation of crop factor for more information.

Larger sensors also perform better in low light, although in most cases, you’re unlikely to notice. The real benefits of full frame cameras are often that they’re built like tanks for professionals and have more manual controls and options.

RELATED: What is DSLR Crop Factor (And Why Should I Care)

Do I Need a Full Frame Camera?

Most people don’t really need a full frame camera. If you’re just getting into photography, there’s no need to upgrade. Whatever you’ve got lying around—or even your smartphone—is perfect for learning.

However, if you’re in the market for a camera and budget isn’t a concern, what you probably want is a full frame mirrorless camera. For more on that, check out my camera buying advice over on our sister site ReviewGeek.

RELATED: Is It Worth Buying a Mirrorless Camera Yet?

Profile Photo for Harry Guinness Harry Guinness
Harry Guinness is a photography expert and writer with nearly a decade of experience. His work has been published in newspapers like The New York Times and on a variety of other websites, from Lifehacker to Popular Science and Medium's OneZero.
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