Are you confused about what the letters EF and EFS mean on your Canon camera lenses? It’s a common question, especially when you’re just starting out with photography. These labels can seem a bit tricky, but figuring them out is really important for getting the right gear.
Don’t worry, we’ll make it super simple and show you exactly what you need to know, step by step. Ready to clear things up? Let’s get started on what makes ef lens vs efs so important.
Understanding Canon Lens Mounts EF vs EFS
When you look at Canon cameras and lenses, you’ll often see two main types of lens mounts: EF and EFS. Knowing the difference between them is key to making sure your lenses work with your camera. It’s not about which is better, but which is right for your specific camera body.
This choice affects what kind of photos you can take and how your camera performs.
What Does EF Mean?
EF stands for “Electro-Focus.” Lenses with the EF mount are designed for Canon’s full-frame DSLR cameras. Full-frame cameras have a larger sensor, which is the part of the camera that captures the image. When you use an EF lens on a full-frame camera, you get the full field of view that the lens was designed for.
Think of it like this: the sensor is big, and the lens covers that entire big area.
These lenses also work on Canon’s APS-C sensor DSLR cameras. APS-C is a smaller sensor size. When an EF lens is put on an APS-C camera, something called a “crop factor” comes into play.
The camera sensor is smaller than the image circle projected by the EF lens. This means the camera only uses the central part of the image. It’s like looking through a window that crops the edges off the full picture.
This makes the lens appear to have a longer focal length. For example, a 50mm EF lens on an APS-C camera will behave more like a 80mm lens (50mm multiplied by the typical crop factor of 1.6).
EF lenses offer a wide range of options, from wide-angle to telephoto, and are generally known for their excellent image quality and build. They are compatible with almost all Canon EOS DSLR bodies, both full-frame and APS-C.
What Does EFS Mean?
EFS lenses, on the other hand, are specifically designed for Canon’s APS-C sensor DSLR cameras. The “S” in EFS stands for “Special,” meaning they are optimized for the smaller sensor size. These lenses project a smaller image circle that perfectly matches the APS-C sensor.
This means there’s no wasted image area and no need for the camera to crop the image.
Because EFS lenses are built for a smaller sensor, they are typically smaller, lighter, and less expensive than their EF counterparts. They are also designed to take advantage of the APS-C sensor’s crop factor. When you use an EFS lens on an APS-C camera, you get the focal length that is listed on the lens, without any apparent magnification due to cropping.
A key point to remember is that EFS lenses are NOT compatible with Canon’s full-frame DSLR cameras. If you try to mount an EFS lens on a full-frame body, it physically won’t fit. The rear element of the EFS lens might also hit the mirror in a full-frame camera, potentially causing damage.
So, if you have a full-frame Canon DSLR, you should only be looking at EF or EF Lenses.
Compatibility: The Big Picture
The easiest way to think about compatibility is this:
- EF Lenses: Work on both full-frame and APS-C Canon EOS DSLR cameras.
- EFS Lenses: Work ONLY on APS-C Canon EOS DSLR cameras.
This is the core of the ef lens vs efs debate for many photographers. If you have an APS-C camera like a Canon Rebel series (e.g., T7i, T8i) or a Canon EOS 70D, 80D, 90D, you can use both EF and EFS lenses. If you have a full-frame camera like a Canon 5D Mark IV, 6D Mark II, or EOS R series mirrorless cameras (with an adapter for EF/EFS lenses), you can only use EF lenses.
Mirrorless cameras often use different mounts (like RF for Canon mirrorless), but adapters allow the use of EF and EFS lenses on these bodies.
Crop Factor Explained
We touched on the crop factor briefly, but it’s worth a bit more attention, especially when considering EF lenses on APS-C bodies. The crop factor is a multiplier that tells you how much the apparent focal length changes when you use a lens on a camera with a smaller sensor than a 35mm full-frame sensor.
For Canon APS-C sensors, the crop factor is typically 1.6x. This means:
- A 50mm EF lens on a Canon APS-C camera acts like an 80mm lens (50mm x 1.6).
- A 24mm EF lens on a Canon APS-C camera acts like a 38.4mm lens (24mm x 1.6).
This can be an advantage if you often shoot subjects that are far away, like wildlife or sports. The crop factor effectively gives you more “reach” without needing a longer, heavier lens. However, it can be a disadvantage if you want to shoot wide-angle scenes, as even a wide lens might not be as wide as you’d expect on an APS-C body.
EFS lenses are designed with this crop factor in mind. A 10-18mm EFS lens, for example, is designed to give you a wide field of view on an APS-C camera. On that same camera, its effective focal length range would be approximately 16mm to 28.8mm (10mm x 1.6 to 18mm x 1.6).
This is a great range for landscapes and interior shots.
Benefits of EFS Lenses for APS-C Users
Since EFS lenses are made for APS-C cameras, they offer several benefits:
- Cost-Effective: Generally more affordable than comparable EF lenses.
- Compact and Lightweight: Often smaller and lighter, making them easier to carry around.
- Optimized Image Circle: The image projected by the lens is the exact size needed for the APS-C sensor, leading to efficient use of the sensor’s pixels.
- Consistent Field of View: The focal length listed on the lens gives you the actual field of view you will get on your APS-C camera without the added complexity of calculating crop factor magnification.
Benefits of EF Lenses for Full-Frame Users
For those with a full-frame Canon DSLR, EF lenses are your only choice. They provide:
- Full Sensor Coverage: You get the intended field of view for every lens.
- Wider Options: Access to a vast range of professional-grade lenses designed for the ultimate image quality.
- Flexibility: Can be used on APS-C bodies if you decide to downsize or use a second camera body, albeit with the crop factor applied.
Can You Use EF Lenses on APS-C Cameras?
Yes, absolutely! As mentioned before, EF lenses are fully compatible with Canon APS-C DSLR cameras. When you mount an EF lens on an APS-C body, the camera automatically detects the lens and applies the crop factor.
This is a great way to start with affordable lenses that you can continue to use if you upgrade to a full-frame camera later.
Can You Use EFS Lenses on Full-Frame Cameras?
No, you cannot. EFS lenses are designed for APS-C sensors and will not fit on Canon full-frame DSLR bodies. The lens mount is different, and the image circle projected by an EFS lens is too small to cover the larger full-frame sensor.
Attempting to mount one can cause damage.
Mirrorless Cameras and Adapters
Canon’s newer mirrorless cameras (like the EOS R series) use the RF mount. However, Canon provides adapters that allow you to use both EF and EFS lenses on their RF mount mirrorless bodies. This is fantastic news for photographers who are transitioning from DSLRs to mirrorless systems, as they can often use their existing lens collection.
When using an EF lens on an RF mount camera with an adapter, you might have the option to shoot in a “crop mode” that mimics the APS-C sensor’s crop factor, or you can choose to use the full-frame sensor area if the lens projects a large enough image circle. For EFS lenses on an RF mount camera with an adapter, the camera will typically default to crop mode, effectively using the APS-C compatible area of the sensor.
What About Third-Party Lenses?
Many third-party manufacturers like Sigma and Tamron also produce lenses that are compatible with Canon’s EF and EFS mounts. When buying from these brands, you’ll see specific mount options listed, such as “Canon EF Mount” or “Canon EF-S Mount.” Always ensure you select the correct mount for your camera body.
Choosing the Right Lens for You
The decision between EF and EFS lenses primarily comes down to your camera body and your photographic goals.
- If you have an APS-C Canon DSLR: You have the flexibility to choose from both EFS and EF lenses. EFS lenses are often a great starting point due to their cost and size. EF lenses offer more options and future-proofing if you plan to move to full-frame.
- If you have a Full-Frame Canon DSLR: You must use EF lenses.
- If you have a Canon Mirrorless Camera: With the appropriate adapter, you can use both EF and EFS lenses, but be mindful of how the crop factor might affect your field of view, especially with EFS lenses.
Consider what you like to photograph. For general-purpose shooting, travel, and everyday moments, an EFS lens on an APS-C camera is often perfect. If you’re aiming for professional portraiture, wide-angle landscapes, or low-light performance where you need the full sensor’s capabilities, an EF lens on a full-frame camera is the way to go.
Frequently Asked Questions
Question: Can I use an EFS lens on a Canon 5D Mark IV?
Answer: No, you cannot. The Canon 5D Mark IV is a full-frame camera, and EFS lenses are only compatible with APS-C sensor cameras.
Question: If I have an APS-C camera, is it better to buy an EF or EFS lens?
Answer: It depends on your budget and future plans. EFS lenses are often cheaper and lighter for APS-C cameras. EF lenses offer more choices and can be used on full-frame cameras later if you upgrade.
Question: What is the crop factor for Canon APS-C cameras?
Answer: The typical crop factor for Canon APS-C cameras is 1.6x.
Question: Will an EF lens work on an EFS mount camera?
Answer: Yes, EF lenses are fully compatible with Canon APS-C cameras that have an EFS mount. The camera will apply the crop factor.
Question: Can I use my old EF lenses on a new Canon mirrorless camera?
Answer: Yes, with the correct Canon EF-EOS R mount adapter, you can use your EF lenses on Canon’s EOS R series mirrorless cameras.
Final Thoughts
Choosing between EF and EFS lenses comes down to your camera’s sensor size and what you want to achieve with your photography. For those with APS-C Canon DSLRs, EFS lenses provide a cost-effective and lightweight solution perfectly matched to your camera. They offer a great way to get started without breaking the bank.
On the other hand, EF lenses are essential for full-frame Canon DSLRs and also offer greater flexibility if you anticipate upgrading to a full-frame system in the future, as they can be used on both sensor sizes, albeit with a crop factor on APS-C bodies. Understanding this distinction means you can confidently select lenses that will perform best for your specific gear and photographic needs. Experimenting with different focal lengths and lens types within your compatible mount is the best way to discover your personal style and preferences.
