Full-Frame vs Crop Sensor | Which One Is the Best?

Have you ever wondered which is better; full-frame or crop sensor cameras? Full-frame vs crop sensor is a common debate.

There’s quite a bit of (mis)information out there; full-frame being ‘better’, for one.

Having used nearly every system (full-frame and crop) out there, I’ve come to realize that both have plenty to offer.

So if full-frame vs crop is a question affecting your first camera purchase, let’s have a look at the advantages and disadvantages of each sensor size.

What Is a Camera Sensor?

Full-frame vs crop sensor? Which one is better? Photo by Qamera from Pixabay.

A camera’s sensor is the digital equivalent of film. It consists of millions of photosites which register and record incoming light.

This is where the megapixel (MP) count of your camera comes from. A 24 MP sensor has 24,000,000 individual photosites or pixels; the more photosites available, the higher the resolution of the photograph.

If your camera is mirrorless, the sensor also acts as the autofocus unit that feeds the electronic viewfinder (EVF).

This is one reason why the battery life of mirrorless cameras is low compared to DSLRs. With no separate phase-detection system or optical viewfinder (plus a smaller, mirrorless body), the sensor has to do a lot more work.

If you remove the lens from an interchangeable lens camera, you can see the rectangular shaped sensor inside. For DSLR cameras, you will need to flip the mirror in order to see it. Photo by Muhammad Ribkhan from Pixabay.

Sensors come in several sizes:

- 7.01 x 5.79mm sensor: The iPhone X has a sensor of this size. While tiny compared to interchangeable lens cameras, this is actually respectable for a smartphone camera;

- 1-inch sensor: The Nikon J1 and Sony RX-100 line have a sensor size of 13.20 x 8.80mm;

The Nikon J1 camera has a 1-inch sensor.

- Micro 4/3rds sensor: This is actually 17.30 x 13.00mm;

- APS-C sensor: This is usually 23.60 x 15.70mm (depending on brand); and

- Full-frame sensor: This is usually 35.00 x 24.00mm (depending on brand).

But sensor sizes don’t stop there. Medium format cameras, such as the Fujifilm GFX line, have 44.00 x 33.00mm sensors.

However, in this article, we’ll be focusing on the differences between full-frame and crop interchangeable lens formats, like APS-C and Micro 4/3rds.

The Meaning of Full-Frame and Crop

Why do we use the terms full-frame vs crop?

Well, full-frame harks back to the days of film. Specifically, 35mm film photography, which–funnily enough–is also a crop format. It is crop because above that you have medium and large format cameras.

When digital sensors came out, the term full-frame helped distinguish the sensors from APS-C, which are considered a crop format.

Full-frame sensors were not the largest digital sensors at the time; the term helped film photographers transitioning to digital understand that equivalency in field of view and depth of field wouldn’t be a factor with a full-frame sensor.

A full-frame Canon camera body. Image by Pexels from Pixabay.

Advantages of Full-Frame

There are a number of advantages to full-frame sensors, including:

- More Megapixels;

- A better dynamic range;

- Better light detection;

- Low light performance; and

- Beautiful bokeh.

So let’s take a look at the key advantages of full-frame sensors in the full-frame vs crop debate.

Do More Megapixels Matter?

Higher resolution does not necessarily lead to better quality photos.

How many megapixels you need is entirely dependent on you. In fact, there are even disadvantages to a higher resolution sensor.

When it comes to full-frame vs crop, full-frame cameras tend to have the highest resolutions, like the upcoming Sony A7IV (61 MP).

More resolution gives you more room to crop a shot without visibly losing image quality. This is useful if you view images on large, high-resolution screens.

High-resolution images also mean more detail if you want to produce large prints.

Full-frame, high-resolution sensors are great if you want to produce large prints. Photo by JuergenPM from Pixabay.

But if you’re sharing most of your images on social media only, a high-resolution camera will not be necessary.

A 12 MP resolution would be more than enough to view on a screen, plus significantly fewer pixels are needed for smartphone viewing.

You don’t look at a photo in a magazine from nose distance. So why would you blow up computer files to check for grain and noise if you aren’t making gallery prints?

You need fewer megapixels than you think you do. High-resolution photos also have massive file sizes, that suck up processing power and hard drive space.

Better Dynamic Range

Photo by Landon Nguyen.

The current standard for both full-frame and crop is 24 MP, which also has a secondary benefit: improved dynamic range.

Dynamic range refers to the range of light and dark tones the camera sensor is capable of rendering. The more refined the gradation, the higher the dynamic range the camera has.

Dynamic range is less about the size of the sensor and more about the photosite quality (in terms of sensitivity and size).

Full-frame sensors do usually have better dynamic range than crop cameras. This is because a 24 MP full-frame sensor has larger individual photosites compared to a 24 MP crop sensor.

Better Light Detection

Another benefit of a full-frame sensor is that the larger photosites are also more efficient at detecting light.

Not only does the total light gathering area of the sensor increase with sensor size, but so do the individual pixels; making full-frame the best choice if you intend to shoot regularly in low light.

Full-frame has its advantages if you shoot high dynamic range scenes. Photo by David Mark from Pixabay.

This means you’ll see a slight reduction in dynamic range and low-light noise performance if you’re using a high-resolution, full-frame sensor, but not as much as you might think.

Technology like back-illuminated sensor (BSI), found in many full-frame (and a few crop sensor) cameras, helps negate the disadvantage of crowding pixels onto the sensor.

Does Full-Frame Equal Better Low Light Performance?

Full-frame cameras tend to produce better images in low-light. Photo by mostafa meraji on Unsplash.

This is a common question with a complex answer: yes and no.

The larger sensor does mean a larger light gathering area, which can translate into better exposure and autofocus performance.

But pixel size also plays a role in low-light performance, as does aperture, which is dependent on your lens, not your camera.

Shutter speed selection, lens vibration reduction, sensor stabilization systems (which tend to be more efficient on smaller sensors), and tripods also help narrow the gap, depending on what you’re shooting.

As a rule, though, you will get a cleaner image using a lower ISO with a full-frame camera.

Full-Frame Equals Beautiful Bokeh

Larger sensors also create a shallower depth of field for a given aperture and focal length.

For example, if you’re using a 35mm f1.4 lens on a full-frame body like the Nikon D800, you’ll get a depth of field of approximately 0.16m from a subject distance of 1.5m.

If you use that same 35mm f1.4 lens on an APS-C body, like the Fujifilm X-Pro 2, you’ll get the full-frame lens equivalent of a 50mm f2 in terms of depth of field and field of view.

Full-frame sensors create a shallower depth of field for a given aperture. Photo by Pexels from Pixabay.

In short: a smaller sensor means you have to use faster lenses (wider apertures) to get the same shallow depth of field. As a very rough rule of thumb, you move back a stop of aperture in terms of the depth of field appearance per step from full-frame (APS-C, Micro 4/3rds, 1-inch).

If you’re a portrait photographer who wants the best bokeh for his buck, the best option for you would be a full-frame sensor.

Full-Frame Cameras Look Professional

And lastly, there’s the marketing hype surrounding the term ‘full-frame’. Crop seems to suggest ‘inferior’ to full sensor size; despite the fact that that full-frame is actually a crop format.