Camera Parts

Digital camera sensor size

Written by Bernard Dery

The size of a digital camera sensor has a big impact on image quality, especially when taking photos in low light.

Digital camera sensor sizes

Relative sizes of digital camera sensors - Graphic courtesy of Cambridge in Colour*

The size of a camera sensor will have a big impact on the quality of your pictures. The lens gathers light and directs it towards the sensor, and the sensor records the light to create the image.

Large sensor produces better images

All things being equal, a larger sensor will receive more light than a smaller one, and produce better images. This is especially important in low light photography.

When light levels are low, a smaller sensor will generate a higher amount of noise, which will decrease the quality of the images. This is why the best low-light setups include a camera with a large sensor, such as a digital single lens reflex camera, and a lens with a large aperture.

Compact digital camera sensors

In the compact world, most sensors are generally around the same size. Sensor size for compacts is calculated by measuring the sensors diagonally. The most common sizes are 1/2.5 (0.4) and 1/2.3 (0.43) inches. Pretty small by all accounts.

Backside-illuminated CMOS sensors, such as those found in the Canon SD4000, are small but generally do better in low light than CCD sensors. They also provide faster continuous shooting speeds.

Larger compact camera sensors

Manufacturers have started including larger sensors in some of their compacts. For instance, Canon’s s95 camera has a 1/1.7 (0.58) niches sensor. This represents a total area 37% larger than most comparable models, and yields much better low light pictures. Compact cameras like the Panasonic LX5 also sport larger sensors. [Related article: Low light pocket cameras]

Pixel density

One thing to keep in mind is that the size of each individual pixel is what will truly define the performances of the sensor. In other words, more pixels over the same area means that noise levels will increase, because each individual pixel will receive less light.

DSLR sensors

The sensor in a typical digital single lens reflex camera is many, many times larger than the sensors found in compacts. This means that DSLRs are much better at taking low-light pictures with low noise. But even in the DSLR world, there are differences between sensors.

The larger sensors are called “full-frame” and are found in some higher-end, professional bodies. The size of these sensors is equal to that of 35 mm film, with a 1.7 inches long diagonal.

The vast majority of DSLRs have sensors slightly smaller called APS, with a 1.18 inches diagonal (48% of the area of the full frame sensor). The use of the APS sensor allows smaller lenses to be designed while still preserving most of the optical performances of the sensor.

Another sensor size used in DSLRs is called Four Thirds (0.85 inches diagonal). This system, while being slightly less efficient in low light, makes possible the use of extremely small lenses. This sensor size is used in the “Micro Four Thirds” system, which is a bridge between compacts and DSLRs.

Visit our Amazon shop for a list of compact digital cameras with larger sensors

*Copyright © Cambridge in Colour

About the author

Bernard Dery

Bernard was born and still lives in Quebec City, Canada. A doctorate candidate in Physics, Bernard works full-time as an optical designer at EXFO, a world leader in telecom tests and measurements tools. His professional interests go from fiber optics to atmospheric data collection and lasers.

His first contact with photography was a Vivitar fixed lens camera that he had purchased at age eight. His interest developed slowly, and for many years Bernard limited himself to family and travel pictures.

Bernard discovered the world of digital photography in February 2004, when he purchased his first digital camera. Developing an interest for composition, he experimented with many subjects: landscapes, nature, cities and architecture.

Bernard
soon began to invest more time and energy into his new found hobby, finding new and beautiful subjects to capture everyday. His challenge is to capture the mood and emotion carried by a scene as it presents itself to him.

A trip to Italy in
September 2004 fueled his growing interest with numerous magical photography opportunities.

Bernard and his wife like to spend free time near a lake at his family's summer house, where he finds new subjects to capture every day. His interests are varied and include hiking, camping, swimming, boating and reading, as well as most winter
sports.

Bernard, known as bdery on forums, uses a Pentax K20D and W80, Canon S2 and a Nikon SQ as a backup.

Thumbnails are of photos by Bernard Dery - used with permission
Copyright Bernard Dery All rights reserved

5 Comments

  • Thanks for a very helpful article. Only started to learn about sensor size as i am finding my compact digital camera has very poor indoor performance. So I am on the look for a better performing camera.

    To tap into your expertise, it would help people like me to narrow the search down if could add a list of cameras and their sensor size.

    Thanks again.

  • Danny, you are correct that larger sensors existed in the past. There have been a few years when they were all but absent, and now they are beginning to appear again. I did not want to go into to much history in this short article.

    You are also correct that a larger sensor will help isolate subject from background, but only indirectly. The sensor itself has no impact on this, however a larger sensor will allow the use of a longer focal length to obtain a given field of view, and a longer focal length helps diminish the depth of field.

  • It’s not only recently that some compacts have had 1/1.7″ sensors. My first digital camera, bought in 2002, is a Fuji 4800 and it has one.  3 years ago I bought a Sony H2, and assumed it would be better in every way.  However, I noticed that at 400 ASA photos on the Fuji have less noise.
    Another advantage of a larger sensor is that you can throw backgrounds out of focus.  I don’t want to go back to the days of a heavy SLR with extra lenses, but I would like a camera with a decent zoom, large sensor and a hot shoe that’s not too expensive.  Perhaps one of these new micro four thirds will eventually suit.