The size of your camera’s sensor is important because it affects image quality. Between two cameras with the same pixel count, the one with the physically larger sensor will produce better quality images. This is due to the fact that photo receptors, which we now call pixels, are bigger on the larger sensor.
The primary purpose of a photo receptor is to collect light and produce an electrical signal that is then converted into a digital image signal, and the more light that is received by the sensor, the stronger the image signal will be.
Strong signals do not need as much amplification, and this means there is less occasion for image noise to be introduced or enhanced.
The most expensive component of a camera is typically its sensor, and this means that cameras with larger sensors tend to be considerably more expensive than cameras with smaller sensors.
The body of the camera also generally needs to be made bigger to house the larger sensor and to accommodate the lenses that are necessary to generate the larger image circle.
To summarise in general terms, cameras with bigger sensors tend to be larger and more expensive than those with smaller sensors, and they produce better quality images.
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Bigger camera sensor or fewer pixels?
As mentioned earlier, bigger sensors allow the pixels to be made bigger and this has a positive influence on image quality, with a reduction of noise levels and an extension of dynamic range. Similar results can be achieved by keeping the pixel count down with a smaller camera sensor size.
Higher pixel counts, however, are frequently seen as a positive thing because images are larger and it allows for more detail to be recorded.
The challenge for manufacturers is to reduce noise levels and preserve image quality at the higher sensitivity settings when light levels are low.
Some cameras like the Nikon D4S offer advanced low light performance by having a reasonably low pixel count (16 million in the case of the D4S) and a large (full-frame) sensor.
This makes them quite versatile, but the images are not particularly large, and those wanting to produce big images with a lot of detail should select a high pixel count camera such as the Nikon D850, which has 45.7 effective megapixels on its full-frame sensor.
This camera has the ability to resolve a huge amount of detail, but it’s not the best choice for shooting in very low light. It will be interesting to see how the 50-million-pixel Canon EOS 5DS performs when it goes on sale in June this year.
How Does Sensor Size Impact Resolution?
Sensor size plays a significant role in determining a camera’s resolution and overall image quality. While resolution is often associated with the number of megapixels, sensor size impacts how those megapixels are distributed and the quality of light each pixel can capture. Understanding the relationship between sensor size and resolution is essential for evaluating a camera’s performance and suitability for specific types of photography.
Larger sensors generally have more surface area, allowing for larger individual pixels compared to smaller sensors with the same resolution. Larger pixels can capture more light and reduce the impact of noise, particularly in low-light conditions. This leads to better dynamic range, improved color accuracy, and sharper images. Conversely, smaller sensors pack the same number of megapixels into a smaller area, resulting in smaller pixels that can be more prone to noise and limited dynamic range.
While resolution is measured in megapixels, a camera with a higher megapixel count doesn’t automatically produce better image quality. Larger sensors with moderate megapixel counts often outperform smaller, high-resolution sensors because their larger pixels can collect more light and retain more detail. For example, a full-frame camera with 24 megapixels typically delivers superior image quality compared to a smartphone sensor with the same resolution, due to its larger sensor and pixel size.
Sensor size also affects the ability to crop and enlarge images without losing detail. Larger sensors can maintain higher image quality when cropping because their larger pixels preserve more information. This is particularly beneficial for wildlife or sports photographers who often need to crop into distant subjects. Additionally, larger sensors allow for high-resolution images that can be printed at larger sizes without noticeable loss of detail.
Resolution aside, sensor size affects the effective field of view. Smaller sensors apply a crop factor to the lens, effectively magnifying the image and reducing the field of view. While this doesn’t directly relate to resolution, it influences how photographers compose their images and use their lenses.
Manufacturers often balance sensor size and resolution based on the intended use of the camera. Medium format cameras feature large sensors with high resolutions (e.g., 50+ megapixels) for professional work requiring exceptional detail. Full-frame cameras provide a balance between resolution and portability, while APS-C and Micro Four Thirds sensors prioritize compactness and affordability at the expense of light capture and dynamic range.
Sensor size impacts resolution in more ways than just pixel count. Larger sensors with appropriately sized pixels offer superior light capture, reduced noise, and better image quality, even at similar resolutions to smaller sensors. Understanding this relationship helps photographers choose the right equipment for their needs, whether it’s achieving low-light performance, retaining detail in large prints, or maximizing portability without sacrificing image quality.
What size is your sensor?
Full-frame cameras are called such because a full frame camera sensor size is the equivalent to a frame of 35mm film (26x24mm). APS-C format cameras are called such because their sensor is about the same size as the Classic format on the smaller APS-C format film.
These sensors generally measure 23.6×15.7mm in Nikon, Pentax, and Sony cameras or 22.2×14.8mm in Canon cameras. The Micro Four Thirds format uses a smaller camera sensor size which measures 17.3x13mm.
The size of the sensor inside many compact cameras and some compact system cameras is frequently given in imperial measurements that are based upon a system that was used for old television cameras. These measurements use fractions, which confuses things a bit and manufacturers can be rather cagey about giving actual dimensions.
However, a 2/3-inch sensor measures around 8.6×6.6mm and is larger than a 1/1.7-inch (7.6×5.7mm) and a 1/2/3-inch (1/0.6667-inch or 5.76×4.29mm) sensor.
While full-frame and APS-C format sensors are typically found in DSLRs and compact system cameras, there are some compact cameras that have these larger sensors.
These are first-rate compact cameras that are designed to stand-in for an SLR. There are also large compact or bridge cameras that have relatively small sensors and some small compact system cameras (like the Pentax Q-series) that employ sensors that are more frequently found in compact cameras.
It is worth your time to check the sensor size of a camera in addition to its pixel count when you are considering a purchase.
What are the advantages of small sensors?
Small sensors may not match the performance of larger sensors in terms of light capture and dynamic range, but they offer distinct advantages that make them ideal for certain types of photography and use cases. Their compact size, versatility, and cost-effectiveness have made them a popular choice in smartphones, compact cameras, and action cameras.
One of the main advantages of small sensors is their ability to enable compact and lightweight camera designs. Cameras with small sensors, such as point-and-shoots or smartphones, are highly portable and convenient, making them perfect for casual photography, travel, and everyday use. This portability ensures that you can capture moments without the bulk of larger camera systems.
Small sensors also naturally produce a deeper depth of field compared to larger sensors when using the same aperture and focal length. This makes them excellent for situations where keeping more of the scene in focus is essential, such as landscape, architectural, or macro photography. For beginners, this deeper depth of field reduces the risk of unintentionally blurring parts of the subject, resulting in sharper overall images.
Cameras with small sensors are generally more affordable than those with larger sensors, both in terms of the initial purchase price and the cost of compatible lenses. This affordability makes them a great entry point for hobbyists or those on a budget who want to explore photography without a significant financial commitment. Additionally, the crop factor of small sensors effectively increases the focal length of lenses, providing greater magnification. This is particularly beneficial for wildlife or sports photography, as it allows photographers to achieve longer effective focal lengths with smaller, more affordable lenses.
Small sensors also enable faster image processing, which translates to quicker autofocus performance and higher burst shooting rates. These benefits are valuable for capturing fast-moving subjects, such as in sports or action photography. Furthermore, the smaller file sizes generated by small sensors reduce storage demands and speed up image processing, which is advantageous for photographers who need to capture and share images quickly or work with limited storage capacity.
Small sensors are well-suited for specialized photography and videography applications. For example, action cameras like GoPros use small sensors to deliver wide-angle footage in compact, rugged devices, while drone cameras benefit from the lightweight and compact design enabled by small sensors. While small sensors may lack the dynamic range, low-light performance, and depth of field control of larger sensors, their strengths in portability, affordability, and versatility make them an excellent choice for casual photographers, travelers, and those working in specialized imaging environments.
What are the advantages of big sensors?
Large sensors offer numerous advantages that make them a top choice for professional photographers and serious enthusiasts. Their ability to capture more light and detail results in superior image quality, particularly in challenging lighting conditions. Cameras with large sensors, such as full-frame or medium format models, are known for their exceptional dynamic range, low-light performance, and flexibility in creative control.
One of the key benefits of large sensors is their ability to produce better image quality by capturing more light per pixel. This is due to the larger surface area of each pixel, which reduces noise and enhances the dynamic range of the image. This advantage is especially noticeable in low-light situations, where cameras with large sensors can maintain clarity and detail without excessive grain or digital artifacts.
Large sensors also allow for a shallower depth of field, making it easier to achieve subject isolation and create aesthetically pleasing background blur, or bokeh. This makes large sensors ideal for portrait photography and other creative applications where selective focus is desired. The ability to control depth of field more effectively adds an artistic dimension to photography that is harder to achieve with smaller sensors.
Another advantage of large sensors is their ability to retain detail even when cropping images. With more data captured across the larger surface area, images from large sensors can withstand significant cropping while maintaining sharpness and resolution. This is particularly useful for wildlife or sports photographers who may need to crop in on distant subjects without losing image quality.
Large sensors also excel in color reproduction and tonal gradation, making them a preferred choice for landscape, commercial, and fine art photography. Their ability to capture subtle variations in tone and color results in more realistic and visually striking images, even in high-contrast scenes.
While cameras with large sensors are typically heavier and more expensive, their benefits in image quality, creative flexibility, and overall performance make them indispensable for professionals and those looking to push the boundaries of their photography. Whether shooting portraits, landscapes, or detailed product shots, large sensors offer unmatched capabilities that help photographers achieve their creative vision.
Focal length magnification
If a lens that is intended for a full-frame camera is mounted on a model with an APS-C format sensor, the image circle is much bigger than is required to cover the smaller sensor.
Consequently, the image will look like a cropped version of the one captured with the full-frame camera, or like the lens has been zoomed in to a longer focal length. Because of this, smaller sensors are frequently referred to as having a ‘crop’ or ‘focal length magnification’ factor.
This is intended to describe how images will look relative to those shot on full-frame cameras. Canon APS-C format SLRs have a 1.6x magnification factor while Nikon models have 1.5x magnification.
This means that on APS-C format a 100mm lens will produce images that resemble those captured at 160mm on a full-frame Canon camera, while the effective focal length of the same length lens on a Nikon APS-C format camera would be 150mm.
Usually, compact camera lenses are usually marked with their actual focal length, which due to the very small camera sensor size are often just a few millimetres.
They are, however, more frequently discussed in terms of their effective focal length. The Canon Ixus 27 HS, for example, has a 1/2/3-inch sensor and a lens with a focal length of 4.5-54mm.
However, this optic is typically called a 25-300mm lens because that is its equivalent focal length on a full-frame camera.
Other camera sensor sizes
While full-frame bodies are esteemed for their larger than average camera sensor size, in the hay day of film 35mm cameras were in fact known as ‘small format’ models.
Medium format cameras that took 120 film and produced negatives that measures 6x7cm, 6x6cm, or 6×4.5cm were a common choice for professional photographers and devoted enthusiasts.
However, those who wanted the best in image quality chose large format cameras that took sheets of film and produced images that measures 10×8 inches or 5×4 inches.
While there are digital medium format cameras available these days, their high price tag puts them securely in the sphere of professional photographers.
Their sensors, however, are actually much smaller than medium format negatives and regardless of its name, even the Pentax 645Z possesses a sensor that actually measures 44x33mm rather than the 60x45mm negatives of its film-based namesake.
Sensor Format Dimensions
- Medium Format: 53.7 x 40.2 mm, Aspect Ratio 4:3, Crop Factor ~0.64
- Full Frame: 36 x 24 mm, Aspect Ratio 3:2, Crop Factor 1.0
- APS-H: 28.7 x 19 mm, Aspect Ratio 3:2, Crop Factor 1.3
- APS-C: 23.6 x 15.6 mm, Aspect Ratio 3:2, Crop Factor 1.5
- Micro Four Thirds: 17.3 x 13 mm, Aspect Ratio 4:3, Crop Factor 2.0
- 1-inch: 13.2 x 8.8 mm, Aspect Ratio 3:2, Crop Factor 2.7
- 1/1.7-inch: 7.6 x 5.7 mm, Aspect Ratio 4:3, Crop Factor ~4.6
- 1/2.3-inch: 6.17 x 4.55 mm, Aspect Ratio 4:3, Crop Factor ~5.6
What is the relationship between sensor, lens and Depth of Field?
Depth of field (DoF) refers to the area in a photograph that appears sharp and in focus. It is a critical aspect of composition, allowing photographers to isolate their subject with a blurred background or keep the entire scene sharp from foreground to background. Depth of field is influenced by a combination of factors, including the camera’s sensor size, the lens’s aperture, the focal length, and the distance between the camera and the subject.
Sensor size plays a significant role in determining depth of field. Larger sensors, such as those in full-frame cameras, produce a shallower depth of field compared to smaller sensors like APS-C or Micro Four Thirds when using the same lens and aperture. This occurs because larger sensors require longer focal lengths or closer shooting distances to achieve the same framing as smaller sensors, inherently reducing the depth of field. For example, a portrait captured on a full-frame sensor at 85mm f/2.8 will have more background blur than the same shot taken with an APS-C sensor at an equivalent framing. This makes larger sensors highly desirable for portraits and creative photography where subject isolation is key.
The lens itself is another critical factor in controlling depth of field. A lens with a wide maximum aperture, such as f/1.4 or f/2.8, can produce a very shallow depth of field, ideal for creating a smooth, blurred background (often referred to as bokeh). The focal length of the lens also matters; telephoto lenses, such as 200mm, naturally produce a shallower depth of field than wide-angle lenses, like 24mm, even at the same aperture setting. This characteristic is why telephoto lenses are often preferred for close-ups and selective focus, as they can isolate the subject more effectively.
The interaction between sensor size and lens characteristics is crucial to understanding depth of field. Photographers using smaller sensor cameras may need lenses with wider apertures or longer focal lengths to achieve the same shallow depth of field effects that larger sensors naturally provide. On the other hand, larger sensors offer greater flexibility, allowing photographers to achieve a shallow depth of field without requiring extreme lens settings.
In practical terms, shallow depth of field is ideal for isolating a subject, such as in portraits or product photography, where a blurred background enhances the subject’s prominence. In contrast, a deep depth of field is essential for landscapes or architectural shots, where sharpness throughout the frame is necessary. Using a smaller aperture, such as f/8 or f/16, combined with a shorter focal length, can help achieve this effect.
By understanding how sensor size and lens characteristics interact, photographers can make more informed choices to control depth of field and achieve their desired creative results. Whether capturing dreamy portraits with soft, blurred backgrounds or detailed landscapes with sharpness from front to back, mastering this relationship is key to elevating photographic artistry.