Canon EF versus EF-S - What's the practical difference?

[Max_Schröder]

Hi everyone

I've (once again) been looking at Canon's tele-lenses in the 250mm and more area.
Now I noticed that most of those are working with the EF-mount, rather than EF-S.
I understand that EF-S was introduced for cameras with a smaller sensor, like my EOS 700D (Rebel T5i), while EF is mainly supposed to be used with the full-frame sensors of Canons professional cameras.
If I'd mount an EF-lens on my camera (which is claimed to be possible), what'd be the actual difference to EF-S lenses?
Is there anything I'd have to do different to get good results?
Maybe someone even has experience of that combination, and can tell me the differences.

Thanks in advance,

Max

 

[jaomul]

No different if mounted on a crop sensor. Some ef lenses might be considered better than efs lenses when used on crop sensor because the best part of lens in the centre is used, and the extremes at edges are not, but this is a general statement and not necessarily true for all lenses

 

[Overread]

Focal length is always the same no matter the format you use. A 250mm lens on a crop sensor is still 250mm on a fullframe camera as it is on a medium format camera.

What changes though is the angle of view. A larger sensor will have a larger angle of view, whilst a smaller sensor a tighter one (for the same focal length). In practical terms this means a 250mm lens on a crop sensor will "appear" longer (in focal length) compared to if you use the same 250mm lens on a fullframe camera body.

This is why cropped bodies are called "cropped" because its like the middle of the frame is "cropped" out when compared to fullframe 35mm (this is because 35mm became "the" standard for many).



Ef lenses work perfectly on crop sensor bodies and there is no downside at all. Indeed if anything you can sometimes see better performance in general because the edges of the frame are often the most optically weak and with crop sensor many edge areas are "cropped" out (ok they are simply not captured).


EFS lenses are beneficial because they:
1) Are typically smaller and lighter due to needing less glass as they don't have to throw such a large angle of view. This can also make them a bit cheaper than equivalents.
2) Cover focal length groupings in zoom lenses that are not offered on fullframe. This is often things like 18-50 or 18-85mm options - wider minimum angles than on typical EF lenses to account for the tighter angle of view.

 

[TCampbell]

Suppose Canon made two identical lenses save for the fact that one is "EF" and the other is "EF-S" (they don't, btw)... what you would find is that there would be absolutely no difference in the images from these two lenses... at all.

Focal length is focal length. A 50mm lens is a 50mm lens. Canon does not list the specs for the EF-S lens as "full frame equivalent" (common in small point & shoot cameras) -- rather the focal lengths are actually true.

The "angle of view" will change because the crop-sensor camera records a smaller section of the image than the larger sensor camera ... thus decreasing the "angle of view" and causing the resulting images to appear as though you've "zoomed in" a bit tighter for the shot (of course... you could just shoot with a full frame camera and "crop in" on those images too... and you'd get the same result.

This might make you wonder... if all of this is true, then what is the point of the "EF-S" lens?

The answer is cost. A full frame camera needs a lens that can project an "image circle" into the body large enough to cover the 36mm x 24mm sensor - which means it needs a diameter of at least 44mm to do this. But an APS-C camera has a sensor which is roughly 23mm x 15mm and that only needs an image circle which is 28mm across.

Since the camera doesn't need the large image circle, Canon can build a lens in which all of the elements are a bit smaller. Smaller elements actually make it easier to control problems such as dispersion (which creates chromatic aberration around the edges of the image). In other words, YOU can get a lens which costs less, is smaller, and weighs less, than an equivalent "EF" lens and NOT have to sacrifice image quality. It's a win-win.

The only down-side is that if, someday, you should choose to buy a "full frame" camera, those EF-S lenses cannot be used on the full-frame camera.

 

[Derrel]

EF-S lenses are pretty much useless on anything except Canon APS-C digital cameras, because they cannot be mounted on the other types of Canon EOS cameras.

EF lenses have full compatibility on all Canon EOS bodies, including their 35mm film cameras, APS-H cameras meaning the 1D series, FF Canon's like the 1Ds series,the 5 D series, and the 6D, and also all of the canon APS-C cameras.

 

[TCampbell]

EF-S lenses are pretty much useless on anything except Canon APS-C digital cameras, because they cannot be mounted on the other types of Canon EOS cameras.

EF lenses have full compatibility on all Canon EOS bodies, including their 35mm film cameras, APS-H cameras meaning the 1D series, FF Canon's like the 1Ds series,the 5 D series, and the 6D, and also all of the canon APS-C cameras.

Except that the focal length ranges are nice on APS-C bodies. E.g. if you have an APS-C camera and want a general purpose zoom, the options are a bit more limited. All the "EF" working zoom lenses have focal lengths that start at either 24mm and up... or 28mm and up. That doesn't offer much wide-angle option. The EF-S zoom lenses usually start around 18mm and up.

 

[zombiesniper]

With all the tech answered and answered more precisely than I ever could, the next question to answer is what type of photography do you wish do do with a larger than 250mm lens?

I like wildlife (mostly bird) photography and for a crop body you can't go wrong with the 400mm f5.6. If you're talking sports then you'll likely want to be able to zoom and be able to shoot in less than optimal lighting conditions.

 

[BillWYellowstone]

I may be wrong, I have been before. The statement that a 250mm is a 250 mm as I understand is not correct. a 250 mm EF lens, when mounted on a crop frame is equivalent to 400mm because the crop factor is 1.6. Multiply the focal length by 1.6 to get effective focal.

The caveat about the upgrade is very valid, it was cheaper for me to buy my 5D Mklll than it was to replace all my EF-S lens.

 

[KmH]

A 250 mm EF-S lens on a EF-S body is equivelent to a 400 mm lens mounted on a EF camera body.

It stays a 250 mm lens regardless the body it is mounted on.
The effective focal length also stays constant.
The only practical difference when a 250 mm is on a crop sensor body is the field-of-view (FoV) is smaller.

You can get the same effect by making a photo with a 400 mm on a full frame body, and then cropping the photo 1.6x to make the FoV equivelent to a 250 mm on a 1.6 crop sensor camera.

 

[Dao]

I may be wrong, I have been before. The statement that a 250mm is a 250 mm as I understand is not correct. a 250 mm EF lens, when mounted on a crop frame is equivalent to 400mm because the crop factor is 1.6. Multiply the focal length by 1.6 to get effective focal.

The caveat about the upgrade is very valid, it was cheaper for me to buy my 5D Mklll than it was to replace all my EF-S lens.

If you mean equivalent Field of View or Angle of View, then it is true. However, lens with focal length of 250mm will always be 250mm regardless the size of the recording medium since it is a physical property of the lens.

 

[Overread]

Remember "fullframe" ergo 35mm isn't magical. It's just that in the film area it became "the" standard for the hobby shooter and a good few pros too. It certainly was not the only film size and was not without its flaws as well as its gains.

Digital has "crop" sensors because early on the cost for making 35mm digital sensors was too great to make them mass marketable to the "common customer"; so they brought in "crop" cameras and the term "crop" got stuck on them because they were "cropped" compared to the traditional 35mm film size most photographers of the time were used to.


For someone who has only shot digital and only shot crop sensor the "250mm" lens on crop sensor is "normal" to them. The whole "It's like something different on a different sensor" doesn't really matter to them and is a point of interest but not critical to know unless they are looking to add a fullframe camera to their setup and want to know how it will change things.

 

[Big Mike]

EF-S lenses are pretty much useless on anything except Canon APS-C digital cameras, because they cannot be mounted on the other types of Canon EOS cameras.

EF lenses have full compatibility on all Canon EOS bodies, including their 35mm film cameras, APS-H cameras meaning the 1D series, FF Canon's like the 1Ds series,the 5 D series, and the 6D, and also all of the canon APS-C cameras.

This is true, except that you can modify an EF-S lens to allow it to mount onto a full frame camera. There is a danger than the back of the lens might interfere with the mirror in the camera, but it can be done.

A pro photog friend of mine, uses an EF-S 10-22mm on a 1Ds mkIV fairly often.

Of course, the smaller image circle from an EF-S lens will cause a vignette on a full frame, especially on the wide end of the zoom.

But even with the difficulties and limitations, he really likes that lens.