Important Things You Must Know About Sensor Sizes

Understanding Camera Sensor Sizes In Digital Photography is crucial because the size of a sensor determines the image quality of photographs. In this article, we cover what a sensor is and how the various sizes affect image quality. Furthermore, we discuss what sensor sizes could be ideal for you based on the environments you shoot in or the subjects you aim to capture. , Important Things You Must Know About Sensor Sizes

1. What Is A Camera Sensor?

A camera sensor is a flat solid-state device covered in millions of pixels that translates an optical image into an electronic signal. It does this by using each pixel to record the number of light photons entering them. This digital information is then delivered to a camera’s processor and converted into an image that matches what the photographer sees. This example is oversimplified but serves well as a basic introduction to the device and concept.

2. What Are Sensor Sizes And Why Are They Important?

Digital cameras offer a variety of sensor sizes. The size of which will have a large part to play in the overall quality of an image. DSLR and Mirrorless cameras offer the largest sensor sizes and thus higher image quality.

It is a common assumption to believe that the megapixel count of a lens equates to image quality. This belief, however, is incorrect. Image quality rests on the size of sensors. This rule is because larger sensors have an increased ability to gather and record light. And as photography is fundamentally about recording light, the more light captured, the more detail there will be in an image. The size of the pixels on a sensor also plays a crucial role in image quality, meaning more aren’t necessarily better.

There was once a time where the megapixels on a camera did count. When cameras offered counts in the 3-10MP ranges, it was impossible to achieve high-quality prints with the photographs. especially if they were large prints. This issue, now resolved thanks to high MP counts, the continuous increase is becoming more to do with marketing than offering photographers better equipment. However, high MP counts are still important for photographers wishing to make large prints with their photographs.

Because larger sensors can capture more light, it makes them outperform smaller sensors in low light conditions. A camera can use faster lenses with wide apertures to help increase the light that hits the sensor. However, nothing will substitute for using a larger sensor.

Another misconception is that by using a smaller sensor, cropping will occur. Again, this is a false assumption. As long as the camera using the smaller sensor uses a focal length that matches a full-frame equivalent, it will capture the same image without cropping.

3. Types Of Digital Camera Sensor

Digital cameras use two types of sensors: CMOS and CCD. Each of these uses a different technology, and both have their strengths and weaknesses.

3.1. CCD (Charge Coupled Device) Sensors

CCD sensors translate pixel measurements by following a sequence, using circuitry that surrounds the sensor. These sensors were more common in older models of digital cameras. It used to be that a CCD sensor could offer superior image quality to CMOS sensors with better dynamic range and noise control.

However, these sensors are now largely replaced by CMOS sensors. This replacement is due to a CCD sensor being more expensive to produce and requiring more power to perform. CMOS technology has also improved so much that it can offer the same if not superior image quality.

3.2. CMOS (Complementary Metal Oxide Semiconductor) Sensors

CMOS sensors translate pixel measurements simultaneously, using circuitry from within the sensor itself. This technology requires less power and increases the speed at which the sensor can record images. This increased speed makes it ideal for high-speed capture in burst shooting modes.

4. Sensor Sizes

4.1. Full Frame – 36 x 24mm

Full Frame- Important Things You Must Know About Sensor Sizes

Full-frame sensors are the same size as analogue film rectangles. Most common in DSLRs and mirrorless cameras, these sensor sizes offer superb image quality compared to other smaller sensor sizes on the market.

Full-frame sensors were once targeted at high-level professionals only, as their prices were so high. However, as sensor technology has evolved, the price has lowered to a point where it is now possible for even amateur photographers with a larger wallet to purchase them.

Full frame sensors once meant larger cameras. However, this is no longer the case. Many manufacturers are now able to include these sensors in smaller bodies. They have even appeared in compact camera bodies. However, due to the sensor size, it does mean the lenses must remain bigger.

4.2. APS-C – 23.6 x 15.8mm (varies)

APSC - Important Things You Must Know About Sensor Sizes

The most common sensor size in beginner and semi-professional system camera models is the APS-C. It applies a crop factor between 1.5x 1.7x depending on the manufacturer. This sensor size is also becoming more common in compact cameras.

While APS-C sensors lack the image quality of their full-frame counterparts, they do give some distinct advantages. Firstly, due to the crop factor, they can zoom in on subjects better with smaller lenses, making them ideal for sports and wildlife photography for the minimalist weight-conscious photographer. Secondly, they are often much cheaper than full-frame cameras, making them suitable for people with restrictive budgets.

Unless you plan to shoot lots of night sky photography or produce extra large prints, an APS-C camera will suit your needs perfectly. Sensor quality also has a large part to play. To summarise, don’t be put off by this smaller sensor. It is large enough to produce stunning results away from low light situations.

4.3. Four Thirds – 17.3 x 13mm

4/£ - Important Things You Must Know About Sensor Sizes

Roughly a quarter of the size of a full-frame sensor, micro 4/3rds sensors are popular in system cameras for videographers. This specialisation is because larger sensors are not required to capture high-quality video. For example, a GoPro 10 with a 1/2.3″ sensor can capture video in 5.3k. The compact body of these sensors makes it easier for videographers to carry the extra equipment needed to make video, such as gimbals.

However, due to the smaller sensor size, they are not ideal tools for photography. And with a 2x crop factor, focal lengths are effectively doubled to achieve the full-frame equivalent. Meaning a 25mm lens will make a 50mm full-frame equivalent.

4.4. One Inch – 9 x 12mm


In recent years one-inch sensors have become the standard for compact cameras. This increased sensor size has allowed compact cameras to increase their image and video quality while remaining small enough to fit into a pocket.

Some compact cameras also offer APS-C sized sensors and even full frames. However, an increase in sensor size also means a price increase.

4.5. 1/1.7 Inch – 7.53 x 5.64mm

1/1.7 Inch - 7.53 x 5.64mm

This size used to be the standard for sensors in compact cameras. However, with the decrease in prices of premium system cameras, the camera manufacturers realised they needed to increase the quality of their compact offerings if they were to remain attractive options. It is rare to find this size of the sensor in compact cameras nowadays.

If you are in the market for a compact camera, make sure you take note of its sensor size and opt for an option with a one-inch sensor rather than this size. Even if the price tag is a little higher, the added image quality will be worth the added cost.

4.6. 1/2.3 Inch – 6.17mm by 4.55mm

 1/2.3 Inch - 6.17mm by 4.55mm

Common in budget cameras, smartphones and action cams, this sensor size is among the smallest on offer today. Unfortunately, using a sensor of this size will mean a noticeable drop in image quality compared to larger sensors. This drop in image quality is especially evident in low light situations where a sensor of this size will struggle.

However, in well-lit environments, these sensors can still yield good results. Furthermore, due to their small size, they are fitted to devices that can be with you at all times. This compact element makes them perfect for backup cameras to capture moments you may otherwise miss when you do not have a larger sensor at hand.

5. The Best Sensor Size

5.1. Full-Frame

The best sensor size is relative to your needs as a photographer. Depending on the subject matter you shoot, your style of shooting, and the weight/space of the gear you wish to carry, your perfect sensor size could be any of the previously mentioned sizes.

If you are primarily shooting to make large poster-sized prints, you should go no smaller than a full-frame camera. If your budget allows, a larger medium format sensor would be the best option if you are willing to spend a lot of money. As discussed, this larger sensor size means you will get the best resolution and dynamic range possible from your images. Full-frame and medium format sensors are popular among landscape, Astro, portrait and fashion photographers for this reason.

However, the larger sensor sizes also come at a cost. Because the sensors are more sizeable, it also means that the bodies and lenses are too. This added size and weight make them unsuitable for photographers who wish to remain more lightweight and nimble on their feet.

5.2. APS-C

APS-C sized sensors are perfect for photographers looking for a more compact set-up than a full-frame kit can provide. The reduced size and weight can help a photographer go farther for longer while allowing more room in a rucksack for other field necessities such as tents, sleeping bags and cooking equipment. Furthermore, as long as the intended purpose for the image is not extra-large prints, an APS-C sized sensor will still yield quality results.

5.3. Four-Thirds

Micro four-thirds sensors, although much smaller than full-frame, can still offer photographers professional results. These sensors are best suited for videographers but also for photographers looking for more discreet systems. Concerning photography, a micro four-thirds camera can be a perfect companion for street photographers where subjects need to remain unaware of a camera to capture those candid moments.

5.4. Smaller Sensors

Regarding smaller sensors such as those found in smartphones, it is more important to remain aware of the computational elements offered in conjunction with the camera. Although not suited for professional photography, these sensor sizes are perfect at documenting everyday life or the things involved in a photoshoot that are not the final images themselves.

6. Conclusion

If you are at the start of your photography journey and are looking to invest in a camera, it will pay dividends to fully understand what you wish to photograph and how you intend to do it. Because sensor size plays such a crucial role in image quality, making sure you choose a sensor size that is correct for you is a vital decision. One of the most important you will make.

That said, photography is not as reliant on gear as one may think. A photographer with lower quality gear that understands the necessities, such as lighting and composition, will still produce better images than those with the better kit but a worse understanding of photographic principles.

Ultimately training your eye in these principles is the best way to achieve high-quality images. So don’t be disheartened if you are unable to purchase the latest and greatest full-frame camera. Some photographers win competitions with dated smartphone cameras.

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David Davis
David Davis
Hi, My name is Dave, and I am passionate about photography. I am currently travelling to document the world's most interesting people and places. I have started this blog to share these incredible sights and experiences with you, including all the knowledge I gain as a photographer/videographer along the way. If you share a passion for street, documentary, and travel photography, join the mailing list and stay up to date with the latest posts and resources direct from the field.

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