I'm wondering if you can mount an EF-M lens directly on a Canon DSLR body. I'm aware that electronic communication won't work, but I can use manual focus with electronic shutter.

If anyone is curious about the use case, I'm eyeing a Venus Laowa 9mm 2.8 EF-M mount lens (also available with many other crop mounts), and it would be so convenient to use it directly on my 70D, without needing any adapter.


No, it is not possible.

Canon DSLR bodies have 44 mm flange focal distance. This is to make room for the mirror.

EF-M mount has only 18 mm flange focal distance. There is no mirror, so no need to make room for it.

The EF-M lens, if mounted on DSLR body, would be too far away from the sensor.

In the other direction, things are much better. A mirrorless body can take nearly any DSLR lens with a suitable adapter. You might be limited to manual focus only, though.


No. They are physically different mounts, with different dimensions, shapes, and sizes. EF-S lens on the left; EF-M lens on the right.

EF-S and EF-M lens mounts side-by-side; Wikimedia commons image

If the lens fits the EF-M mount, it will not fit the EF-S one without some type of physical linkage adapting. But even if there were such an adapter, you would never achieve the full range of focus to infinity with one, because the depth of the mounts is also different.

EF/EF-S mount is 44mm deep; EF-M is 18mm. So, any EF-M lens would be sitting 26mm farther away from the sensor than it's designed to sit. This would be like using a macro extension tube, and would restrict the ability of the lens to focus at the far end. And that distance is probably far too large to be made up for with a teleconverter element in any adapter.

See also: Can I use lens brand X on interchangeable lens camera brand Y?

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