Best Sensor Sizes For Outdoor Surveillance Cameras

The sensor is a crucial component of a digital camera, capturing light and converting it into signals to create an image. The size of the sensor determines how much light is used to create the image, with larger sensors producing better quality images than smaller ones.

The size of the sensor also determines the camera's viewfinder, with larger sensors capturing more of the scene. The standard full-frame sensor size is the same as a traditional 35mm film frame, measuring 35mm by 24mm. This is the largest sensor size commonly available in consumer cameras, typically found in advanced and professional models.

Smaller sensor sizes include APS-H, APS-C, and Four Thirds, which are commonly used in interchangeable lens cameras. The Four Thirds system, used by Panasonic and Olympus, is about a quarter of the size of a full-frame sensor and has a 2x crop factor.

When choosing a camera sensor size, it's important to consider factors such as image quality, low-light performance, camera and lens size, depth of field, and cost. While larger sensors generally provide better image quality and low-light performance, they also require larger and more expensive lenses. Smaller sensors are more compact and lightweight, making them suitable for travel and hiking. Ultimately, the choice of sensor size depends on the specific needs and preferences of the user.

Camera Sensor Sizes: Full Frame, APS-C, Micro Four Thirds, 1, 1/2.55

Full Frame Sensors

Full-frame sensors are the largest type of sensor commonly available to consumers. They are equivalent in size to 35mm film (36mm x 24mm) and are considered the industry standard. Full-frame cameras tend to be larger and heavier than cameras with smaller sensors, but they offer superior low-light performance and dynamic range, resulting in better image quality. Full-frame cameras are typically used by professional photographers and are ideal for low-light photography, large prints, and situations where maximum detail and dynamic range are required.

APS-C Sensors

APS-C sensors are smaller than full-frame sensors and are commonly found in beginner and intermediate-level cameras. The specific dimensions of APS-C sensors vary depending on the camera brand, but they generally measure around 23mm x 15mm. APS-C sensors have a crop factor, which means they crop the image and provide a narrower field of view compared to full-frame sensors. The crop factor for APS-C sensors is typically 1.5x for Nikon and Sony cameras and 1.6x for Canon cameras.

Micro Four Thirds Sensors

Micro Four Thirds sensors are even smaller than APS-C sensors, measuring 17.3mm x 13mm. They are commonly found in interchangeable lens cameras from brands like Panasonic and Olympus. Micro Four Thirds sensors also have a crop factor, which is typically 2x. Cameras with these sensors are known for their compact size and lightweight design, making them a popular choice for travel photographers.

1-Inch Sensors

1-inch sensors are commonly used in compact cameras and bridge cameras. They measure 12.80mm x 9.60mm and are large enough to capture a decent amount of light. Cameras with 1-inch sensors offer a good balance between size and image quality.

1/2.55-Inch Sensors

1/2.55-inch sensors are typically found in smartphone cameras, such as the iPhone 11. They are on the larger end of the spectrum for smartphone sensors and provide decent image quality for casual photography. However, smartphone sensors are generally much smaller than those found in dedicated cameras, which can result in lower image quality, especially in low-light conditions.

Camera Sensor Resolution: Megapixels and Image Quality

The image sensor is the region of a digital camera that's sensitive to light and records an image when active. The size of the camera's sensor determines how much of this light is used to create the image.

Megapixels

Megapixels are a measure of the number of individual photosites on a sensor. Photosites are light-sensitive spots on the sensor that record information about what is seen through the lens. One megapixel is a grouping of 1,000,000 (one million) pixels. A camera's resolution is also sometimes displayed as a multiplication sum, e.g. 6000 x 4000 pixels, which is the number of pixels along the long side and short side of the rectangular sensor.

Image Quality

The more pixels or megapixels the camera has, the more information the camera receives from the sensor, and the better the image quality. However, the story of camera resolution doesn't start and end with megapixels. Other factors, such as pixel size, sensor size, and lens resolution, also play a part.

Sensor Size

The size of the sensor determines how much light it uses to create an image. A bigger sensor can gain more information than a smaller one and produce better images. Larger sensors also allow manufacturers to increase the resolution of their cameras without sacrificing too much in terms of other image quality attributes.

Pixel Density and Pixel Pitch

Pixel density is the number of pixels in a given area. The more pixels you have in that area, the higher the pixel density. Pixel pitch is the distance between the centre of one pixel and the adjacent pixels. A larger pixel density value and a smaller pixel pitch value give you better resolution.

Pixel Size

Smaller pixels give you better resolution. For example, a one-inch square sensor with 120 pixels spread over its entire surface area will give a better indication of what the photo might be of than a sensor with only four pixels. However, pixels lose sensitivity as they get smaller. Larger pixels are more sensitive, passing more detailed information to the camera processor, which is why cameras with a slightly lower MP count can have better low-light performance (reduced noise) and better dynamic range.

Camera Sensor and Image Quality: Low-Light Performance

The size of a camera's sensor is a key factor in determining its performance in low-light conditions. A larger sensor can capture more light, resulting in better image quality and improved low-light performance. However, it's important to note that bigger doesn't always mean better, and other factors such as pixel size, lens aperture, and sensitivity also play a significant role in low-light performance.

Sensor Size and Low-Light Performance

A larger sensor means that the camera can collect more light, which is crucial for capturing high-quality images in low-light environments. This is because a larger sensor has a bigger surface area, allowing more light to reach the sensor. As a result, larger sensors generally perform better in low-light conditions compared to smaller sensors.

However, it's worth noting that the relationship between sensor size and low-light performance is not linear. While a full-frame sensor will typically provide better low-light performance than an APS-C or Micro Four Thirds sensor, the difference may not be as significant as one might expect. Additionally, advancements in sensor technology have enabled smaller sensors to achieve impressive low-light performance, narrowing the gap between larger and smaller sensors.

Pixel Size and Low-Light Performance

The size of individual pixels on a sensor also impacts low-light performance. Larger pixels can capture more light, resulting in improved low-light performance. This is because each pixel acts as a "well" that collects photons, and a larger well can gather more photons, leading to better low-light performance.

However, increasing the size of pixels usually results in a lower resolution sensor since a larger pixel size means fewer pixels can be accommodated within the same sensor size. This trade-off between resolution and low-light performance is an important consideration when choosing a camera for low-light photography.

Lens Aperture and Low-Light Performance

The lens aperture plays a crucial role in determining the amount of light that reaches the sensor. A larger lens aperture allows more light to pass through, improving low-light performance. However, increasing the lens aperture reduces the depth of field, which can be a crucial consideration for applications with varying working distances. Therefore, a careful balance between aperture size and depth of field is necessary when designing a low-light imaging system.

Sensitivity and Low-Light Performance

Sensitivity refers to the ability of an image sensor to convert incident photon energy into electrical signals efficiently. Cameras with higher sensitivity can convert low-light images into high-quality outputs, making them well-suited for low-light photography. Responsivity is a similar concept, indicating the efficiency of the sensor in converting photons from a low-light scene into detailed images. Cameras with higher sensitivity or responsivity will generally perform better in low-light conditions.

Other Factors Affecting Low-Light Performance

In addition to the factors mentioned above, other aspects of camera design and technology can influence low-light performance. For example, advancements in image processing algorithms, as seen in the Google Pixel 8 Pro, can significantly enhance low-light image quality. Additionally, features such as image stabilization can help reduce camera shake, allowing for slower shutter speeds and improved low-light performance.

Camera Sensor and Angle of View: Focal Length and Crop Factor

The image sensor format of a digital camera determines the angle of view of a particular lens when used with a particular sensor. The size of the image sensor is usually measured in millimetres or inches.

The crop factor, format factor, or focal length multiplier of an image sensor format is the ratio of the dimensions of a camera's imaging area compared to a reference format. In the case of digital cameras, the reference format is often a 35 mm film format. The most commonly used definition of crop factor is the ratio of a 35 mm frame's diagonal (43.3 mm) to the diagonal of the image sensor in question.

The crop factor is sometimes used to compare the field of view and image quality of different cameras with the same lens. The focal length of the lens does not change by using a smaller imaging area; the field of view is correspondingly smaller because a smaller area of the image circle cast by the lens is used by the smaller imaging area.

The angle of view can be calculated using the formula: angle of view (a) = 2 multiplied by the inverse tangent of your sensor size (either vertical, horizontal, or diagonal) divided by twice your given focal length (FL).

The crop factor can be used to calculate the "equivalent focal length", which is the focal length needed to produce the same angle of view on a 35mm camera. This can be calculated by multiplying the lens's focal length by the camera's crop factor. For example, a 50mm lens on a camera with a crop factor of 1.5 will have an effective focal length of 75mm, as 50 x 1.5 = 75.

Different types of cameras have different standard sensor sizes. For example, the sensor sizes used in DSLRs include APS-C and Full Frame, while the sensor sizes used in compact cameras include 1/1.7-inch, 1/2.3-inch, and 1/2.7-inch. The sensor sizes used in mirrorless cameras range from Full Frame to 1/2.3-inch, and can include APS-C, Micro Four Thirds, and 1-inch sensors.

Camera Sensor and Depth of Field: Aperture and Focal Length

The depth of field (DOF) is the distance between the nearest and farthest objects that appear acceptably sharp in an image. The image sensor format of a digital camera determines the angle of view of a particular lens when used with a particular sensor. The size of the image sensor in a camera determines how much light it uses to create an image. Larger sensors can gain more information and produce better images.

The size of the aperture (the "f-number") and the focal length of the lens are the two most important factors in determining depth of field. The aperture is the opening in the lens that allows light to pass through to the image sensor. The focal length of the lens is the distance between the lens and the image sensor when the subject is in focus.

A larger sensor will have a wider angle of view when used with a lens of a given focal length, resulting in a narrower field of view. This is known as the "crop factor" or "focal length multiplier". A larger sensor will also have a shallower depth of field when used with the same lens and aperture settings as a smaller sensor. This is because the larger sensor captures more of the out-of-focus areas around the subject, resulting in a shallower depth of field.

However, it is important to note that depth of field is not solely dependent on sensor size. The same depth of field can be achieved with different sensor sizes by adjusting the distance to the subject and the focal length of the lens. Additionally, the effective focal length of a lens is dependent on the sensor size and can affect the depth of field. The effective focal length is the focal length of a lens when used with a particular sensor size, and it is equal to the physical focal length multiplied by the crop factor.

In summary, while sensor size can indirectly affect depth of field by influencing the choice of lens and shooting distance, it is not a direct factor in determining depth of field. The key factors in determining depth of field are the aperture, focal length, and distance to the subject.

Frequently asked questions