Has the APS-C Sensor Got a Future?

I found myself in possession of two, (three if you count the IR converted Canon 550D) cameras boasting APS-C sensors. This has happened more by accident than design and it got me thinking. Contrary to the flow of popular opinion, has the APS-C Sensor got a future?

What are the Most Common Sensor Formats?

The most commonly used formats for sensors are, in decreasing order of size, Medium Format, Full Frame, APS-C and Micro Four Thirds.

Medium Format is much loved by professionals, Full Frame is found on many DSLRs and Mirrorless cameras eg. Canon R5, Canon 5D.

APS-C is also found in many DSLR and Mirrorless cameras eg Canon R7 and 7D, R50v and Micro Four Thirds on smaller, lighter cameras made by OM-System (formerly Olympus) and Panasonic.

What is an APS-C Sensor

APS-C is one of the image sensor size standards for interchangeable-lens cameras.

It is called APS-C 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. It is important to note that since there is no formal 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. This incidentally has an effect on the “zoom factor” Canon is roughly 1.6 while Nikon is 1.5.

What is the Difference Between APS-C and Full Frame?

There are differences between APS-C and full-frame in terms of sensor size, angle of view, bokeh, dynamic range, and low light shooting.

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 as the light travels from the edge of the photo, through the lens to the sensor. The bigger the sensor the shallower the angle.

Zoom

This size differential leads to the perception that APS-C sensors “zoom in” on a subject.

When photographing a subject from the same point using the same lens, the area captured in a photo with an APS-C size camera will be smaller than with a full-size camera. This is because the APS-C size sensor is smaller than the full-size sensor and can only therefore receive a “slice” of the light reflecting from the subject and it’s surrounds, coming through the lens.

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

Bokeh

Compared to full frame, when the same shot is taken, 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 deeper area in focus than the full-size sensor, the amount of blur in the background appears smaller.

Dynamic Range

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. The traditional wisdom is that 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 more light each pixel in the sensor receives. Modern manufacturing techniques are making real inroads into this perception, to the extent that the difference is barely noticeable.

Low Light Shooting

When shooting in dark environments, exposure is often secured by increasing the ISO, thus amplifying the signal but if ISO is raised too high, noise may become noticeable especially in the shadows and more noticeably when these shadows are lightened in post processing.

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

Which Companies Support APS-C?

Cameras

Several camera manufacturers offer APS-C sensor cameras. The most notable include Canon, Fujifilm, Nikon, Sony, and Pentax. Note that there. is no standard lens mount, each company has developed their own and systems for APS-C sensors, such as Canon’s EF-S and EF-M mounts, Nikon’s F and Z mounts, and Sony’s E-mount are very different. Fujifilm also has its own X-mount system for APS-C. 

Lenses

Obviously the camera manufacturers also make lenses supporting their camera, but there is a growing market in high quality, weather sealed lenses provided by companies like Sigma and Tamron that are more affordable and in some cases arguably superior to lenses provided by the camera manufacturer.

What Advantages does APS-C Bring?

APS-C cameras offer several advantages, centred around compactness, affordability, and the telephoto effect. 

Size

Because of the reduced sensor size, APS=C cameras are often smaller and lighter than full-frame cameras, making them ideal for travel and street photography. My newly acquired Canon R50v ‘s width is less than the length of my hand. A less imposing camera is hard to imagine.

Zoom Effect

The crop factor effectively increases the focal length of lenses, providing a telephoto reach for subjects like wildlife and sports. 

Affordability

In terms of affordability it makes more financial sense to buy an APS-C camera than it does to buy a new full frame lens to get the equivalent focal length.

For example, the Sigma 16-300 costs around €700 new. On a Canon APS-C camera it has an equivalent focal length of (16-300) x 1.6 or (25-480). In terms of equivalence, my Canon R5 II full frame cost approx €3500 and a 100-500mm lens another €3500.

The Canon R7 cost me approximately €1000 and my Sigma 16-300mm superzoom a further €700. This is a compelling difference even factoring in a slight loss of quality. This factor alone is likely to ensure the future of APS-C.

What are the Disadvantages of APS-C?

Perceived disadvantages include lower image quality in low-light, reduced dynamic range, and a crop factor that reduces the field of view. 

Another disadvantage is that lenses designed for APS-C camera cannot be used with full frame cameras because the reduced field of view is “built-in” to the lens. There is no point in designing optics that project a field of view larger than the sensor, unless of course you are designing a tilt-shift lens that uses exactly this principle to support both tilt and shift.

Conclusion

The financials almost guarantee a future for APS-C. It’s not unknown for corporation to crush product lines with reduced profit margins, but the format is widespread and the after market in lenses sufficiently advanced to ensure longevity.

Canon recently shared their RF mount spec with Sigma so that more lenses supporting the format could be brought to market quickly. Rumours suggest that there will soon be an R7 mk II and even a G1x Mk IV with APS-C sensors.

Having stumbled into owning several cameras supporting the format I can attest that the qualitative differences are only really noticeable to the trained eye and the only negative I can muster is that my reaction on buying my first full frame camera, a Canon 5D mk III more than fifteen years ago, my reaction was that the new camera would enable me to take better pictures, That as a landscape photographer was directly related to the reduced field of view.

Further Reading

.Canon R50v Review