What Is an EF-S Lens? How Is It Different from an EF Lens? 

What Is an EF-S Lens featured photo

Do you ever wonder about the definition of the letters on Canon lenses? That makes the two of us. I used to ask myself, “what is EF-S?” when I saw the markings on the lens. But since then, I have learned what it means, and I will share it with you below.

An EF-S lens is a type of Canon lens. It has a smaller image circle than EF lenses to match the smaller sensor size of APS-C cameras. It also sits near the image sensor for a shorter back focus.

Canon EF-S lenses offer several more benefits, which we will explore below. This article also covers the differences between EF-S and EF lenses. It even answers some of your questions about Canon lenses.

What is an EFS Lens?

An EF-S lens is a type of Canon lens. It features a small image circle that covers the entire APS-C sensor. It is designed specifically for APS-C DSLR cameras from Canon, such as the Rebel series. However, it can also fit mirrorless cameras via the proper mount adapter.

The letters “EF-S” stand for electro-focus short back focus. This lens type has a short flange focal distance, allowing glass elements near the image sensor. It creates a short back focus, hence the name.

The short focal distance also makes the EF-S lens compact and lightweight. It is easier to handle compared to equivalent full-frame lenses.

Canon EF-S lenses are available in various focal lengths. These include wide-angle, standard, telephoto, fisheye, and macro lenses.

What Are the Differences Between A Canon EF vs. EF-S Lens?

What Are the Differences Between A Canon EF vs. EF-S Lens

Besides the EF-S lens, Canon produces another type of lens mount called EF.

Now, you may wonder, “what is an EF lens?” Fret not! The section below covers the main differences between Canon EF and EF-S lenses, including their definitions.


As previously mentioned, the Canon EF-S lens refers to electro-focus short back focus. It allows lens elements to be closer to the sensor.

A Canon EF-S lens also features a small image circle that matches the sensor size of APS-C cameras.

In contrast, the Canon EF lens stands for electro-focus only. It has a large diameter that covers the entire full-frame image sensor. It is available in a big range of focal lengths and sizes. 

Camera Compatibility

The Canon EF and EF-S markings on the lenses can also determine their compatibility with cameras.

EF lenses fit a full-frame camera body from Canon. These include models from the Canon EOS 1-6D series. They offer a full field of view, similar to the traditional 35mm film sensor.

Meanwhile, EF-S lenses are exclusive to APS-C cameras or those with crop sensors. These models have smaller sensors than full-frame cameras. They encompass the t3-8 or Rebel camera series.


The Canon EF lens usually has better construction than the EF-S lens. It offers higher-quality glass elements than an EF-S lens. That is because it is designed for full-frame cameras and suits professionals. Some EF lenses are even weather-sealed to protect them from bumps and outdoor conditions.

Meanwhile, Canon EF-S lenses typically use plastic material. Although the build quality is decent, they lack the weather-sealed design that prevents damage from unpredictable conditions. 

That said, an EF lens tends to be large and heavy. It can tire you quickly, especially when traveling. A Canon EF-S lens is smaller and lighter than an EF lens. It is more suitable when shooting for extended periods.

Image Quality

In general, Canon EF lenses have better image quality than EF-S lenses. The reason is they use more advanced optical elements. They are also targeted at professional photographers. As such, they can capture sharper and clearer photos.

However, that does not mean the EF-S lens offers low image quality. It can still produce great photos, but these can lack details.


Canon EF and EF-S lenses also differ in terms of price.

Canon EF lenses are slightly more costly than EF-S lenses for several reasons. These include their construction, image quality, and intended purpose. However, they can retain their price value over time.

EF-S lenses are more affordable. They suit hobbyists and entry-level photographers who often have a limited budget. Unfortunately, they quickly lose value. They are difficult to resell at the same price tag.

Can You Use A Canon EF-S Lens on Full-Frame Cameras?

EF-S lenses are designed specifically for APS-C or crop-sensor cameras. Hence, you cannot use them on full-frame cameras.

Well, technically, you can fit the EF-S lens into a full-frame mount. However, doing so can lead to problems.

For one, a Canon EF-S lens has an image circle that covers the entire APS-C sensor. This is smaller than a full-frame 35mm sensor. So if you use the EF-S lens on an APS-C camera, you can see a large vignette in the picture. You cannot edit or remove this in photo editing software because the lens is too small for the image sensor.

Can You Use A Canon EF Lens On Crop Sensor Cameras?

Canon EF lenses are built for full-frame cameras. However, you can also use them on crop sensor cameras.

These lenses have a large image circle but can still fit cameras with a small APS-C sensor. They will not retain their focal length, though. That is because of the crop factor in cameras.

The crop factor is the ratio of your image sensor size to a 35mm film sensor. It affects the equivalent focal length of a lens when attached to various cameras.

For instance, a 50mm EF lens on a full-frame camera (with a 35mm sensor size) offers the same focal length (50mm). But when connected to an APS-C camera (smaller sensor), the 50mm EF lens acts like an 80mm lens instead.

The reason is the Canon APS-C cameras have a crop factor of 1.6x. To calculate the equivalent focal length of an EF lens on a crop sensor camera, multiply the crop factor (1.6x in this case) by the actual focal range of the lens.

The crop factor can benefit some photographers while alienating others. For example, wildlife photographers prefer the longer focal length the EF lenses can give. However, landscape photographers would probably not like the perspective change. 

It ultimately depends on your needs and preference if you want to use an EF lens on a crop sensor camera. But if you prefer to retain the focal length stated on the lens, you will want to use an EF-S lens instead.

When to Buy EF or EF-S Lenses for Your APS-C Camera

If you own an APS-C or crop sensor camera, you can buy an EF or EF-S lens. Both Canon lenses will technically fit your camera.  

However, an EF lens can change your field of view. It offers a more zoomed-in perspective. So, a wide-angle EF lens will act more like a standard one. Meanwhile, a telephoto EF lens provides a narrower field of view with greater magnification than its stated focal length.

It is up to you to decide if an EF lens fits your photography goals. If you often shoot action, like sports or wildlife photography, this lens type is worth considering.

Otherwise, use an EF-S lens on an APS-C to ensure that your focal length is the one shown on the lens. It suits architecture and landscape photography because it lets you capture a wide perspective. It is also compact and lightweight, which is ideal for traveling. 

How To Tell If My Canon Camera Fits EF or EF-S Lenses?

How To Tell If My Canon Camera Fits EF or EF-S Lenses

It is easy to know if your Canon camera is compatible with an EF or EF-S lens. 

Go to the web and search the phrase, “is it full frame or crop sensor?” and your camera name. If you are unsure of its model, consult your product manual. 

The search results will reveal whether your Canon camera has a full-frame sensor or an APS-C format. 

If you own a full-frame Canon DSLR, you can only use an EF lens.

Those with APS-C or crop sensor cameras can attach EF and EF-S lenses. 

If the search results are inaccurate, you can also check the lens mount on your camera to determine its compatibility with lenses.

A full-frame DSLR will have a red circle or dot on the lens mount. Meanwhile, Canon APS-C cameras have a red dot and a white square.

What Are the Other Lens Mounts For Canon Cameras?

Canon cameras also offer other lens mounts than the standard EF or EF-S mounts. These fit the newer models from Canon’s camera lineup.

EF-M Mount

The Canon EF-M mount is exclusive to EOS M cameras. These are portable and lightweight lenses that suit the mirrorless system. 

However, they have a cropped image circle, which only fits APS-C sensors. They are also not backward-compatible with non-M cameras from Canon. They require an adapter before attaching them to other Canon cameras. But even with an adapter, these lenses may suffer from poor image quality.

RF Mount

Canon full-frame mirrorless cameras use the RF mount.

This lens mount features a 12-pin connection between the camera and lens instead of the standard 8-pin design. It offers faster performance and better image quality than other lens mounts. It is also relatively small and compact, ideal for professional photographers constantly on the go.

RF-S Mount

The RF-S lens mount is intended for Canon APS-C and crop sensor mirrorless cameras. 

It has a similar build to the RF mount. It is light and compact to complement the smaller bodies of mirrorless systems. 

However, it is a relatively new lens mount, so your options might be limited.


Canon lenses have different mount types to suit various cameras. The EF-S lens mount is exclusive for APS-C or crop sensor systems. It has a small image circle and a short back focus that offers several benefits.

Do you have more questions about Canon EF-S lenses? Feel free to send your queries on our contact page.