Soon after getting my Canon M50, I was curious and wanted to know about other canon cameras. There seemed to be a lot of models with different names. But which were the major ones? Soon afterwards, I found the different types of lens mounts. I wanted to know more about which lens mount is for which type of cameras.
A little bit of digging and I found my answers. I am going to lay down my finding in this blog post. Canon has two type of cameras based on the presence / absence of a mirror – DSLR and Mirrorless. And then based on the sensor size – Full Frame and Crop Sensor. They have four different lens mounts for these cameras.
Mirror, Mirror, On The Wall
Canon DSLR cameras have a mirror in front of the sensor. This mirror redirects the light coming in through the lens to the optical view finder. Once the camera shutter is pressed, the mirror is flipped and the light goes directly in and onto the sensor and the sensor records the image.
The mirrorless cameras, as the name makes it obvious, don’t have any mirrors. The light directly falls on to the sensor. And since there’s no mirror to reflect the light, the view finder is digital / electronic / simulated. The lack of mirrors help make the cameras more compact. It also doesn’t require a mechanical shutter anymore, so there can be silent shutters – taking bursts of photos without making any sound. Mirrorless technology is more modern and is being widely adopted these days although, like any topic, there’s arguments both supporting and opposing mirrorless cameras.
Based on mirrors, we have two types of cameras on our hands – DSLR and Mirrorless.
My Canon EOS M50 is a Mirrorless camera. If you look at the sensor, you can see it directly. There’s no mirror in front of it.
Full Frame vs Crop Sensor
Canon makes two types of cameras based on sensor size – Full Frame and Crop Sensor cameras.
Full frame sensors are the same size as traditional 35mm cameras. Crop sensors are cameras with smaller sensors. These are also known as APS-C sensors. Since the sensors are small, if you put a full frame equivalent lens on top of it, it can not use the full image circle generated by the lens, thus causing a crop effect on the image. That’s why these cameras are adorably known as “crop sensor” cameras. You can read more on Crop Factor to better understand the implications.
My Canon M50 is a crop sensor camera with a crop factor of 1.6.
Lens Mount
If we combine these different types of cameras, we have on our hand – Full Frame DSLR and Full Frame Mirrorless cameras and then Crop Sensor DSLR cameras and Crop Sensor Mirrorless cameras. We would also have 4 types of lens mounts for these 4 types of cameras.
But interestingly, some of these mounts are compatible with one another and some can be adapted on another and some are totally incompatible and not even adaptable. It may look a bit confusing at the beginning, but eventually you will get the hang of it.
EF Mount for Full Frame DSLR
In the beginning there was full frame DSLR cameras. Canon used the EF mount for these cameras. This is the most popular and most widely adapted lens mount. There are adapters for EF mount lenses for other camera vendors too.
Sony / Fujifilm users also sometimes choose to adapt an existing EF lens on their camera. It’s often because there are so many cheaper lens choices for the EF mount and some photographers already have expensive Canon lens from their previous setup.
As you can guess, EF lenses can be used with any modern day Canon camera, either directly or via an adapter.
EF-S for Crop Sensor DSLR
Since crop sensors have a smaller size, the lenses don’t need to produce a large image like on full frames. So Canon created the EF-S mount for crop sensor DSLR cameras. This mount is quite similar to the EF mount.
EF-S lenses could be used on EF mounts with a hack (literally) but it would produce heavy vignetting and protruding part of the lens could damage the mirror. So it’s not recommended. However, you can use EF-S lens on EF-M and RF mounts.
RF for Full Frame Mirrorless
The RF mount is for full frame mirrorless cameras and can’t be adapted to any other systems right now. There’s no adapters to adapt RF lenses to any other Canon systems yet.
EF-M for Crop Sensor Mirrorless
The EF-M mount is used on crop sensor mirrorless cameras. Just like RF lenses, these can’t be adapted to any other systems either. This is the least incompatible lens mount in canon eco system.
Compatibility
These are how one lens mount is compatible with others:
- EF lens on EF-S – works natively, no adapters needed.
- EF and EF-S lens on EF-M – works with adapter
- EF and EF-S lens on RF – works with adapter
So why is one kind of lens adaptable while others are not? This happens because of Flange Distance.