Many DSLRs and Mirrorless cameras have what’s called an APS-C sensor inside. The idea of an APS-C sensor is comparable to the 35mm full frame (35mm film) format and 645 (6×4.5 medium format) format digital sensors in that they’re all based on a film size. But what isn’t spoken about very much is APS-C sensor sizes and just how many other APS film standards there are–or were. Before digital photography came along, APS film was an option for photographers who wanted to work with a smaller format than 35mm. There were many different types of APS films for different reasons and needs.

According to Wikipedia’s page, APS (Advanced Photo System) film came in three sizes:

• H for “High Definition” (30.2 × 16.7 mm; aspect ratio 16:9; 4×7″ print)
• C for “Classic” (25.1 × 16.7 mm; aspect ratio 3:2; 4×6″ print)
• P for “Panoramic” (30.2 × 9.5 mm; aspect ratio 3:1; 4×11″ print)

These days, cameras typically use the APS-C format. For a couple of years though, Canon used the APS-H format in a variation their early 1D cameras. This variant was targeted at sports shooters who wanted a tiny bit more reach than full frame cameras allowed them and also wanted a faster shooting rate. The full frame 35mm sensor in the early 1D series cameras was reserved for photographers who wanted higher resolution. With the latest iteration, the 1D X, Canon totally phased out the APS-H standard as far as we know and in favor of a full frame sensor with low megapixels for cleaner high ISO images; which is a demand of the target market.

On the other hand, APS-C is used in cameras from Pentax, Sony, Sigma, Nikon, Fujifilm, Samsung and Canon with Olympus and Panasonic being the only ones that don’t use anything larger than a Four Thirds sensor. But even in APS-C digital sensors, there are two different standards:

• On one side is Pentax, Sony, Sigma, Nikon, Fujifilm, and Samsung. All of these companies use a 1.5x crop factor for their APS-C sensors. Years ago, Sigma used to use a 1.7x crop factor until switching over to the more mainstream side of the wall.
• One the other side is Canon with a 1.6x crop factor. Though slightly smaller than the 1.5x crop factor, the sensors have still performed quite well–but nothing is still able to outdo what Fujifilm is capable of doing due to the design of their sensors and what Sony has been recently churning out.

So how are modern APS-C camera sensor sizes in comparison to the older APS-Classic film size? We checked out B&H Photo’s listings for the following information

• APS-C Classic film size: 25.1 × 16.7 mm
• Nikon D7200 sensor size: 23.5 x 15.6 mm
• Pentax K3 II sensor size: 23.5 x 15.6 mm
• Sony A6000 sensor size: 23.5 x 15.6 mm
• Canon 7D MK II sensor size: 22.4 x 15 mm
• Sigma SD1 Merrill sensor size: 23.5 x 15.7 mm
• Samsung NX1 sensor size: 23.5 x 15.7 mm
• Fujifilm X-T1 sensor size: 23.6 x 15.6 mm

Here’s what that looks like in a visual scheme:

The interesting factor here is that we can get so many different results with different sizes partially due to crop factors. Most of the APS-C sensors are about on par with one another in terms of size, but they’re all a bit smaller than the actual film size was. APS-H is far larger and APS-P is significantly wider and thinner for panoramic shooting.

Today, APS-C sensors are more than capable of producing images that professionals can get behind and some may even use these cameras as a second camera body. They’re also heavily in use with advanced amateurs, hobbyists and semi-professionals. The reason for this has come not only from just how good the CMOS and X Trans sensor technology has come but also has to do with one of the bigger aspects of digital photography: the processor. More and more often, our briefings on new cameras involve manufacturers talking in-depth about the processor in the camera and how much of the work is actually done by it.

To that end, I’m 100% positive that if we took similar photos with an APS-C sensor and a full frame sensor and matched the settings and depth of field, very few people would be able to tell the differences. The only people who would genuinely care are techs–and more often than not those people are more interested in the technology rather than the photography and what can come out of the camera. The truth about today’s world is that no one makes a bad imaging sensor or digital camera.

Back in the film days there were no processors–instead it was all a result of the emulsion design. Processing in the darkroom was and still is akin to post-processing in Adobe Lightroom.

Considering how popular APS-C is amongst consumers, it would be a very interesting idea to see a return of APS-H and APS-P sensors for more specialized markets. Going even further than that, why can’t we see a return of 110 format film cameras but tailored for the digital world?