What is different about the EF vs EF-S mount on the camera? Photos?

I have compared EF vs EF-S lenses and can see the difference on the lens side of the mount, but I only have APS-C cameras available to look at.

What I am interested in is the difference(s) in the camera's mount between APS-C DSLR's (which accept EF-S lenses) and other SLR's (film or digital) that only accept EF lenses.

Can anyone post a couple of closeup photos showing both camera mounts and point out the difference(s)? I would appreciate that.

This is just to satisfy a curiosity because I don't know anybody with a film EOS camera or a 1 series digital camera. Our local camera stores don't seem to stock them either.

Does this help...

Many thanks.

I am not sure about what I am seeing, though. Is the only difference the depth of the surfaces around the rectangular hole from the face of the mount?

My 20D has a circular depression inside the mount, putting the rectangular hole further into the camera. I am not sure what I am seeing in the photo of the 10D, but it would make sense since the only apparent difference in the lens mounts seems to be a circular projection around the rear lens element.

The mirror on the 10D (D30 and D60 also) is larger than the EF-S mount cameras. I can't say the 10D has the same size mirror and mirror box as the 1 series digitals, 5D, or film bodies as I don't have one sitting here to compare it with, but it is much larger than the 20D, 30D and the DREBs. The 10D mirror would hit the extended mount of an EF-S lens. It may make contact just trying to mount the EF-S lens. I don't know that for sure because I have never tried to do it.

Although I have only tried it (succesfully) with one EF-S lens on my 1D2n I can say that the actual mount fits & works. The issues are
An EF-S lens only needs to have a light path (or footprint of the image) large enough to cover the smaller sensor, so if used on a larger sensor there will be an area around the image with no information (exposure) that would look like a dark frame. Depending on the lens the dark area could be round or square.
An EF-S lens CAN protrude further into the sensor chamber (depends on where the final lens element needed to be mounted) and if it protrudes into the path that the mirror must use when being flipped up to take the shot, there is a very serious potential to break or jam the mirror.
In my case I knew all this well in advance, but when I was borrowing the long lens on my 1D2n but had no body cap nearby I stuck my Sigma 18-200 from the 20D that I wanted the long lens on, onto the 1D2n to keep dust out. Later that day, and without thinking I decided to see what would happen if I took some shots with the 18-200 on the 1D2n and luckily the lens doesn't protrude into the chamber so it worked without breaking anything. Amazingly the shots were very good too, but until I got over 80mm they looked like I was shooting through a pipe. If I have done this correctly the shot is here.
http://links.pictures.​aol.com …2MoS1KswEovnZas​AP*&size=l
and if not it is shot 16 in this album. http://****/2plr9g
You will notice the shadowed corners as I was approaching a length that got past the "shooting through a pipe" look.

Hereis one at DPreview (scroll down; 10D vs. 300D)here is the 20D

René Damkot wrote in post #2983156
Hereis one at DPreview (scroll down; 10D vs. 300D)hereis the 20D

Thanks, René. The photo in the first link confirmed what I thought I was seeing in kitacanon's photos.

To those who are describing what an EF-S lens is all about - I fully understand all that, and teach others what they are all about. However, I had never seen the CAMERA side of the EF-only of the mount to learn what the difference is between that and the mount on an APS-C camera such as my 20D that can handle the EF-S lenses.

All of my EOS lenses are EF mount, though I have been able to borrow a couple EF-S lenses. Thus, I saw what the lens side of the mount differences were. I just wanted clarification of what the camera side differences looked like.

I think (not having a crop body) if you look at the mounts, the 20D has a white dot just to the right of the red dot which the 10D does not. EF-S lenses line up the white dot on the lens with the white dot on the body. Am I correct?
I have mounted a non-Canon digital only lens on my 5D and the image was circular since the lens produces a circular image that is smaller than the full frame sensor.

KCMO Al wrote in post #2983320
I think (not having a crop body) if you look at the mounts, the 20D has a white dot just to the right of the red dot which the 10D does not. EF-S lenses line up the white dot on the lens with the white dot on the body. Am I correct?
I have mounted a non-Canon digital only lens on my 5D and the image was circular since the lens produces a circular image that is smaller than the full frame sensor.

I was examining an EF-S lens (a borrowed 10-22) and an EF (my 24-70 f/2.8L) this morning.

What I found interesting is that the white dot on the EF-S lens is offset from where the red dot is on the EF lens by the same distance between the two dots on the 20D camera. In other words, the actual alignment of the bayonet portion of the two lens types is precisely the same. It's just the dots that are different.

My guess is that they put a white dot only on the EF-S lenses so that people would not try to mount them on an EF-only camera body by matching the red dots. With the offset, if you match the white dot on an EF-S lens to a red dot on an EF-only camera body, you cannot get the mount to connect.

There appears to be virtually NO difference in the actual bayonet mount on both lens types. The main difference is a circular projection (which goes into the camera) around the rear element of the EF-S lens. The 20D has a circular recess behind the mount that allows the projection on the EF-S lens to fit into it. From the photos I have seen here of a 10D, there is no recess behind the standard EF mount to accept the circular projection of the EF-S lens.

A bit rushed, and without a tripod using natural light where possible, plus my first attempt to upload a photo here.

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Looks like I did that correctly. As can be seen the EF-S 18-200 does fit the 1D2n, and at 18mm on the 1.3 crop sensor has a bit of the tunnel effect. due to the small opening in the rear of the lens.

cicopo wrote in post #2983693
Looks like I did that correctly. As can be seen the EF-S 18-200 does fit the 1D2n, and at 18mm on the 1.3 crop sensor has a bit of the tunnel effect. due to the small opening in the rear of the lens.

If I "read" your photos correctly, you have a Sigma lens there which - though designed for APS-C cameras - is not an actual EF-S lens. It does not have the extra projection at the back of the lens that Canon uses on their EF-S lens family to keep them from being mounted on EF-only bodies. That's an advantage, of course, for owners of the 10D.

Thanks for the photo of the EOS-1D body's mount. That adds to my understanding of the differences in the camera side of the various mounting options.