What is APS-C size? Explanation of the differences and advantages from full-size lenses

Cameras with APS-C sensors are more compact and handy than cameras with full-size sensors, and are widely used by both beginners and professionals. On the other hand, there may be some unexpected differences between APS-C size and full-size cameras, as well as how to select lenses. This article provides a wide range of explanations, from basic knowledge of the APS-C size to the advantages of using it and suitable shooting situations.

APS-C size is one of the image sensor size standards for interchangeable-lens cameras. It is called APS-C size because it has a sensor size (approximately 24 mm x 16 mm) similar to the APS-C (Advanced Photo System type-C) film format among film cameras. However, since there is no strict size standard, the sensor size differs slightly among camera manufacturers. For example, Nikon (DX format) and Sony have a sensor size of approximately 23.6 mm x 15.8 mm, while Canon has a sensor size of approximately 22.3 mm x 14.9 mm.

There are several types of sensor sizes for interchangeable-lens cameras, but generally APS-C size or full-size is the most common. There are differences between APS-C size and full-size in terms of sensor size, angle of view, bokeh, dynamic range, high sensitivity shooting, and size. These also lead to their characteristics. Let's take a closer look at the differences between them.

There is a big difference in sensor size between full-size and APS-C size cameras. The full-size sensor is approximately 35 mm x 24 mm, while the APS-C sensor is approximately 23.6 mm x 15.8 mm. This difference affects the appearance and angle of view of the photos we will introduce next.

When photographing a subject from the same location using the same lens, the area captured in a photo with an APS-C size camera will be narrower than with a full-size camera. This is because the APS-C size sensor is smaller than the full-size sensor and can only receive a portion of the light coming through the lens.

As a result, images taken with an APS-C size camera look about 1.5 to 1.6 times larger (sometimes called the “telephoto effect” because the image appears to be magnified like a telephoto lens).

When the same subject is photographed at the same angle of view, the bokeh effect appears larger with a full-size camera than with an APS-C size camera. This is because the APS-C size sensor is smaller than the full-size, resulting in a deeper depth of field.

Depth of field refers to the area that appears to be in focus in a photograph, and since the APS-C size sensor has a wider area in focus than the full-size sensor, the amount of blur in the background appears smaller.

The range of brightness and darkness that can be recognized by the sensor is called dynamic range. The wider the dynamic range, the less likely it is that whites will be blown out or blacks will be blurred, and the more beautifully and smoothly light/dark differences and gradations (tones) can be expressed in a single photo. Generally, the larger the sensor size, the wider the dynamic range.

Therefore, the full-size sensor tends to produce more beautiful tonal gradations than the APS-C size sensor. This is because the larger the sensor size, the lighter each pixel (pixel) in the sensor receives.

When shooting in dark environments, exposure is secured by increasing the ISO sensitivity, but if the ISO sensitivity is raised too high, noise may become noticeable. As mentioned above, the full-size sensor has a larger sensor size than the APS-C size, allowing it to receive more light.

As a result, even when shooting at the same ISO sensitivity, the full-size sensor can produce less noise. For this reason, full-size cameras are said to be more likely to produce high-quality images when shooting at high sensitivities in dark locations.

Because the sensor size of APS-C size cameras is smaller than that of full-size cameras, both the body and lens are often compact and lightweight. This leads to ease of carrying when heading out to shoot and ease of handling while shooting. APS-C size cameras are especially useful for those who frequently travel or shoot outdoors and want to keep their luggage compact.

However, recent technological advances have made it possible to produce compact full-size cameras. Therefore, it is important to note that “full-size camera = large” does not always mean “large”.

APS-C size cameras have several unique advantages over full-size cameras. Here are some typical advantages.

As mentioned above, the angle of view of an APS-C size camera is narrower than that of a full-size camera, and the subject appears greatly magnified (when shot from the same position with a lens of the same focal length). Therefore, the advantage of the APS-C size is that it is easier to take a large picture of the subject. This telephoto lens-like feature has led some professional photographers to choose APS-C size cameras.

Compared to full-size cameras, many APS-C size cameras are lighter and more compact. For this reason, APS-C size cameras are easy to use when you want to lighten your footwork for long-time carrying, mountain climbing, or traveling.

Lenses for APS-C size cameras also tend to be more compact than those for full-size cameras, so the entire camera and lens set-up is more portable.

APS-C size cameras tend to be more reasonably priced than their full-size counterparts. This has the advantage of making it easy for people who are new to interchangeable-lens cameras to get started. Also, as mentioned above, APS-C size cameras are compact and easy to handle, making them easy to take with you.

This ease of use is an advantage for beginners, as it is important for them to accumulate experience in taking pictures to improve their skills.

Many people may be under the impression that APS-C size cameras are inferior to full-size cameras in terms of image quality, but even photos taken with APS-C size cameras can be of sufficiently high quality that you cannot tell the difference without carefully observing the details. Here are some specific scenes in which you can fully enjoy shooting with an APS-C size camera.

The telephoto effect of an APS-C size camera allows the photographer to capture a large central figure or subject. The narrow angle of view also makes it easier to take pictures that emphasize the subject by suppressing background information. For this reason, APS-C size cameras are useful in many situations for portrait and snapshot photography.

Try using an APS-C size camera when shooting in town or taking commemorative photos of family and friends.

When photographing athletic events, it is necessary to take large pictures of children in the distance. This is where the APS-C size camera's ability to magnify the subject comes into play. Even from a distant spectator's seat, you will be able to take a powerful picture of a child that fills the entire angle of view.

The compact size of the APS-C size camera itself also has the advantage of reducing fatigue even after long hours of shooting. In other sports photography as well, the camera can capture the movements of the athletes in a large format, allowing you to take photos with a sense of realism.

Although an APS-C size camera produces less bokeh than a full-size camera, you can create works that take advantage of the ample bokeh by composing your shots in a creative way. Alternatively, if you take advantage of the small amount of bokeh, it is easy to focus on the entire landscape and take bright, beautiful pictures even with a relatively small f-number. Otherwise, the narrow angle of view is also suitable for capturing a particularly impressive part of the landscape.

Find a distinctive composition in a vast landscape and shoot it with an APS-C size camera.

Although it is often thought that a full-size camera is essential for moon and starry sky photography because of the need for high-sensitivity photography in the dark, an APS-C size camera can also be used for high quality photography. On the other hand, it is possible to take advantage of the narrower angle of view to take pictures that emphasize the moon or constellations as subjects.

Find your own composition and take impressive photos. The principles of starry sky photography remain the same. Keep in mind key points such as adjusting exposure manually and using a tripod.

Birds are one of the scenes where an APS-C size camera is useful, as they require telephoto shooting. Bird photography generally requires an ultra-telephoto lens of approximately 300mm (35mm format equivalent) or more. For example, the TAMRON 150-500mm F5-6.7 (Model A057), when used with an APS-C size camera, provides a focal length equivalent to 225-750mm (35mm film equivalent). This will allow you to take pictures without being alarmed by wild birds.

Also, APS-C size cameras are more maneuverable than their full-size counterparts, allowing you to shoot quickly as the wild.

After purchasing an APS-C size camera, it is important to select the appropriate lens. Here we will explain some important points on how to select a lens for the APS-C size.

There are two types of lenses for interchangeable-lens cameras: lenses for full-size cameras and lenses for APS-C size cameras.

It is possible to mount a full-size lens on an APS-C size camera body, but the angle of view will be cut off. On the other hand, when an APS-C size lens is attached to a full-size camera body, the lens becomes dark on the periphery,
On the other hand, when an APS-C size lens is attached to a full-size camera body, the lens becomes darker in the periphery (vignetting) (with some cameras, this can be corrected using the camera body's settings).

For this reason, we recommend that beginners who are just starting out with a camera use a lens designed for APS-C when using an APS-C size camera.

As mentioned above, lenses for APS-C size and lenses for full size have different angles of view even at the same focal length. Therefore, the angle of view is checked by converting the focal length of an APS-C size lens to that of a full-size lens (called “35mm format conversion”).

As a rough guide, the focal length of an APS-C size lens can be multiplied by approximately 1.5 to 1.6 times* to obtain a focal length equivalent to that of a full-size lens. The table below shows the typical relationship between the focal length of a lens for the APS-C size and its 35mm format equivalent focal length (figures in parentheses are 35mm format equivalent). Please use this as a reference when selecting a lens.
*35mm format equivalent magnification varies by camera manufacturer. The table below shows 1.55x as an example.

The F-number (aperture value) is an indicator of the amount of light entering the camera's sensor through the lens, and the smaller the number, the brighter the aperture of the lens. The F-number at which the aperture is at its widest is called the maximum aperture F-number.

Therefore, the larger the maximum aperture F-number, the easier the lens is to shoot in dark places and to take pictures with blurred backgrounds. This brightness is a big advantage when shooting in dark environments or when shooting fast-moving subjects.

The MOD represents the shortest distance at which the camera can focus on a subject. It is measured as the distance from the subject to the camera's sensor. If you get closer to the subject than the MOD, the camera will not be able to focus on the subject. A lens with a short MOD allows you to get very close to your subject and capture the details of flowers, insects, small objects, accessories, and other objects, making it possible to take impressive photographs. It is recommended that you choose a lens with a short MOD to broaden your range of expressions.

In a zoom lens, the ratio of the focal length at the telephoto end to the focal length at the wide-angle end is called the zoom ratio. For example, in the case of TAMRON 18-300mm F3.5-6.3 (Model B061), the zoom ratio is 300/18 = 16.6x. The larger the zoom ratio, the wider the angle of view a single lens can cover, making it useful in a variety of situations.

Therefore, if you are looking for a lens with high versatility, consider a lens with a large zoom ratio.

AF (Auto Focus) performance is also an important factor when choosing a lens. Check to see if the lens can focus without stress and quickly follow a moving subject.

Especially when shooting sports, children, or animals, AF speed and accuracy are important because of the subject's active movement. If you will also be using the camera for video recording, it is also recommended that you check the AF's quietness.

APS-C size cameras are often useful for telephoto shooting, but it is important to note that telephoto lenses are prone to camera shake. A lens equipped with an in-lens VC (Vibration Compensation) mechanism will effectively suppress the occurrence of camera shake. The VC mechanism is particularly effective when shooting outdoors or in situations where a tripod cannot be used.

APS-C size cameras have features and advantages that differ from those of full-size cameras, such as being compact, easy to handle, and suitable for telephoto photography. Choose the best lens from among APS-C compatible lenses to enjoy photography with ease.