ef-s lens on a ef camera body

[bulwanahill]

Can you use an EF-S lens on a D5 mark 3 camera body in manual mode?

[Waddizzle · Accepted solution]

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@bulwanahill wrote:

Can you use an EF-S lens on a D5 mark 3 camera body in manual mode?

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Negative.  The EF-S mount on a lens is designed in such a way to be incompatible with an EF mount camera body.  Besides, even if you could mount the lens, the image circle projected by the lens would not fully cover a full frame image sensor.  You would see extreme vignetting.  The image would be round with a black border.

[bulwanahill]

Thanks!

[ebiggs1]

"...the image circle projected by the lens would not fully cover a full frame image sensor..."

This would be the least of your worries as the mirror assembly would likely contact the back of the lens.  This would not be a good thing.  The mode of the camera has nothing to do with it.

[bulwanahill]

Thanks

[TCampbell]

The "S" in "EF-S" indicates it's a "short backfocus" lens.  Since these lenses are specifically made for cameras with APS-C size sensors (physically it's about 22mm x 15mm) vs. a "full frame" sensor camera (36mm x 24mm), the EF-S lens is designed to project a smaller image circle and the rear-most element of the lens is actually much closer to the camera sensor than it would be for a full-frame lens.   The rear-most element actually protrudes slightly into the camera body.  They can get away with this because the reflex mirror doesn't need to be as large on an APS-C camera because the sensor isn't as large.  That means the mirror doesn't need as much clearance.

If you were to try to do that with a full-frame body, where the reflex mirror is large, the mirror would likely hit the rear-most element.

Canon designed the mount with a frame that prevents you from being able to attach an EF-S lens to a full-frame body (the same frame is recessed on an APS-C body).  That was done to make sure users don't put the EF-S lens on the full frame body and end up damaging the camera.

So three things:

1.  The lens wont properly seat on the mounting flange (on purpose)

2.  If you could force it on, you'd possibly damage the camera (specifically because the reflex mirror wont have enough clearance to swing clear of the rear element on the lens.)

3.  If you could magically get around problems 1 & 2, you'd find that the image doesn't actually fill the image frame out to the corners.