# Why can a Sigma 10-20mm fit on a "FF" Body?



## Synomis192 (Apr 5, 2013)

Quick question, why does the Sigma 10-20mm f/4.0-5.6 fit on a FF body? I thought that the lens was an EF-s lens since it was for a crop body? I shot with it for fun and it was almost like a fisheye lens. Anyone have that experience as well?


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## gigabellone (Apr 5, 2013)

I have got this lens, but i didn't know it could fit on FF cameras as well. Did you mod the lens in some way, or does it fit as it is?


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## Drum (Apr 5, 2013)

Some one on the forum put pics from a sigma 8-16 up as well. (taken on a FF camera)


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## rats181 (Apr 5, 2013)

Ive tried the lens on my 1D MK IIN and no modification needed it just fits straight onto the camera body. the image circle is smaller as its designed for crop sensor cameras but works none the less.


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## rs (Apr 5, 2013)

While some manufacturers such as Sigma make lenses designed for Canon crop bodies, only Canon make EF-S mount lenses. This means these third party EF crop lenses can physically mount on FF bodies, even though the image circle isn't specifically designed to cover such a large area. Hopefully they have enough mirror clearance too. 

Does the Sigma 10-20 image circle cover the entire frame when zoomed in to say 15/16mm or longer?


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## spinworkxroy (Apr 5, 2013)

When Canon makes EF-S mount lenses, they made the mount different so it won't fit on FF.
For third party brands like Sigma/Tamron/Tokina, they don't make different mounts...cost savings. They make the same mount for all their lenses so even though it's EF-S, they all will mount on a FF camera.
When a third party says their lens is EF-S, it just means the coverage area of the lens is for a crop..when used on a FF camera you will get vignetting or even a big black circle around the image.
Even UWA lens like the Tonkia 11-16 fits a FF and works ONLY at 16mm


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## aj1575 (Apr 5, 2013)

Synomis192 said:


> Quick question, why does the Sigma 10-20mm f/4.0-5.6 fit on a FF body? I thought that the lens was an EF-s lens since it was for a crop body? I shot with it for fun and it was almost like a fisheye lens. Anyone have that experience as well?



The difference between a FF and APS-C camera is not only the sensor, but also some other parts are different in size, due to the different sensors. The smaller sensor in a APS-C allows the use of a smaller mirror as well. Some distances are given in a camera like sensor-shutter, shutter-mirror, mirror-lens; this gives the distance between the sensor, and the back of the lens.

Canon was the only camera maker who decided to use the space freed by the smaller mirror for the lens. This gave them more options to design the EF-S lenses, with the backdraw, that they do not work on a FF body, since the mirror would collide with back of the lens when the mirror flips up.

3rd party lens makers design their lenses to fit on all APS-C cameras, just with a different mount. Since the other manufacturers still use the sensor-lens distance from the FF cameras, these lenses still fit there. This means that you actually should be able to use every 3rd party lens made for Canon APS-C cameras and mount it on a Canon FF body.

I think especially with a wide angle lens the effect is interessting, but normaly it does not make much sense to mount a "cheap" APS-C lens on an "expensive" FF body.


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## dr croubie (Apr 5, 2013)

Last two posts pretty much summed it up, only canon makes it so that their EF-S lenses physically won't fit on an FF body, SigRonKina and RokiBowYang all let them fit. Nikon, not only do they let their DX lenses fit on FX bodies, the FX bodies also auto-crop to a DX (APS-C) sized frame.

FYI: I've put my Sigma 8-16mm on a FF body, and at 15-16mm it not only covers the entire FF image, it beats the EF 16-35L too...


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## Rienzphotoz (Apr 5, 2013)

spinworkxroy said:


> When Canon makes EF-S mount lenses, they made the mount different so it won't fit on FF.
> For third party brands like Sigma/Tamron/Tokina, they don't make different mounts...cost savings. They make the same mount for all their lenses so even though it's EF-S, they all will mount on a FF camera.
> When a third party says their lens is EF-S, it just means the coverage area of the lens is for a crop..when used on a FF camera you will get vignetting or even a big black circle around the image.
> Even UWA lens like the Tonkia 11-16 fits a FF and works ONLY at 16mm


+1


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## KyleSTL (Apr 5, 2013)

rs said:


> While some manufacturers such as Sigma make lenses designed for Canon crop bodies, only Canon make EF-S mount lenses. This means these third party EF crop lenses can physically mount on FF bodies, even though the image circle isn't specifically designed to cover such a large area. Hopefully they have enough mirror clearance too.
> 
> Does the Sigma 10-20 image circle cover the entire frame when zoomed in to say 15/16mm or longer?



A friend of mine bought this lens, and I tried it out on my 5D, I think the hard vignetting stopped at 14mm or 15mm. The corners were quite dark, but it worked out to be a fairly usable 14-20mm IIRC. I did not save any of the test shots I took with it.


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## Synomis192 (Apr 8, 2013)

aj1575 said:


> Synomis192 said:
> 
> 
> > Quick question, why does the Sigma 10-20mm f/4.0-5.6 fit on a FF body? I thought that the lens was an EF-s lens since it was for a crop body? I shot with it for fun and it was almost like a fisheye lens. Anyone have that experience as well?
> ...



Of course we wouldn't want to mount a cheap lens one a pro body. I actually mounted it on my Canon ELAN 7. I loved that super wide almost fisheye distortion that the lens produce. Of course it isn't a money making shot, it does provide a lot of fun images  Also the film gave them a super retro look (I made a mistake developing it. I don't know what I did but it looks funky haha)


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## tombu (Apr 8, 2013)

You can use Canon's 10-20mm on full frame...


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