EF versus EF-S lenses?

[jla930]

What's the difference between EF and EF-S lenses?

[TCampbell]

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@DougLSmith wrote:

I know this is an old posting, but I still wanted to clarify one statement, "the lens does not know what kind of camera you are using it on."  While the lense does not know which camera it is on, a full-frame camera, such as the 5D Mark III or a 6D will know if there is an EF-S lense on it.

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You cannot mount an EF-S lens on a full-frame body such as a 5D series or 6D body.  The lens will not fit.

The rear-most lens element on an EF-S lens would conflict with the reflex mirror on a full-frame body (not to mention it doesn't project a large enough image circle into the camera).  Canon made a subtle change (they put a ledge inside the mounting flange on the full-frame bodies which is not present on the crop frame bodies) which blocks an EF-S lens from being able to "seat" properly on the mounting flange -- this way you cannot accidentally use the lens on the wrong body and damage the camera.

[ebiggs1]

Tim,

"You cannot mount an EF-S lens on a full-frame body such as a 5D series or 6D body.  The lens will not fit"

Oh, but it can be made to fit. There are plenty of "how-to's" on the net but I am not going to even hint on how to do it or even find a tutorial. I repeat this should never be tried. Only bad things will result. Don't do it.

If you are around enough astronomy guys long enough, you will notice some very peculiar and even weird combinations of cameras and lenses.

[Bill-Emmett]

I have seen a Canon EF-S 10-22mm lens converted to a EF lens.  It does not take much time to make the conversion, but a new mount has to be installed on the lens with some other parts.  The lens becomes unuseable at the lower 10-15 mm with a lot of vignetting.   The lens itself, when used on a cropped sensor camera is, IQ wise "L" quality.  When the lens is modified and used on a EOS 5II the IQ is just off a beat.  It would be much better, rather modify, to invest in a EF lens, like the 16-35mm f2.8L to get the actual "L" quality lens and forgo the pitfalls of modifying a EF-S lens for a full frame camera.  

[TCampbell]

I can imagine.  Lens optics are tuned for a specific back-focus distance.  When you mess with that distance, bad things happen to the image.

When we do astrophotography, we can insert a focal-reducer into the image path to give us a wider field of view.  Some focal reducers are also field flatteners.  But most tend to be optimized for a 105mm back-focus distance.  You have to make sure any tubes, adapters, etc. all total up to 105mm.  If you're off, you still get an image (usually even a recognizable image) -- but it's not as good.

[ebiggs1]

EF-S lenses are a slightly different format meaning the sensor is closer to the lens, this is possible due to the smaller mirror with APS-C sensors. The distance from the back of the lens to the image plane is known as the back-focus distance, this is the “S” in EF-S which is short back focus. Sigma has lenses designed for smaller sensors, too, as do others, that have the smaller image focusing but they don't have the same back focus distance.

Moving the lens mount closer makes it easier to design wide angle lenses, but Canon introduced EF-S lenses from scaled down existing lens designs to avoid making new designs.

Example, the EF-S 60mm macro is a 1 to 1.6 of the EF 100mm macro. Sigma and their 50-150mm f2.8 from their 80-200mm f2.8, etc.

As a general rule and probably the best advise, EF-S lenses can not be used on full frame cameras. It can be done but is risky with out certain precautions.

[debraellsworth]

Is there an adaptor that will allow EF S lens to be used on EF Camera

[Bill-Emmett]

No, and there never will.  "S" lenses are made only for the size of the cropped sensor body.  But, a EF lens will mount and work on a cropped sensor body.  

B

[BlaeysOGlory]

I've been looking for info on EF lenses vs EF-S lenses, and stumbled upon this community. I'm glad Canon has a community. Now I finally have a place I can get help.

First, let me start by saying the more I look at different lenses, the more confused I become. I'm very new to photography and I really don't understand what all the different lenses do or why there are so many. I upgraded from a Rebel T3 to a Rebel T6i. There is also the T6s, and now I wonder if I should have gotten that instead. It just seemed to be nothing more than gadgety features, so I settled for the T6i. Now I'm kicking myself for that decision.

My main dillema is that lenses can be extremely expensive. I want to take the best possible picture, but now that I've done some research, I'm not so sure that a crop sensor body was a good choice. I'm just really confused about the whole thing. Also, I was considering getting a new STM lens to replace the older 18-55 lense that I've had since I first got the T3. But I don't really understand what an STM zoom lens is either. I only know that it's newer technology. Do I really need to do this? 

My apologies for all the questions, but if anyone can shed some light, is greatly appreciate it.

Thank you in advance.

[RobertTheFat]

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@BlaeysOGlory wrote:

I've been looking for info on EF lenses vs EF-S lenses, and stumbled upon this community. I'm glad Canon has a community. Now I finally have a place I can get help.

First, let me start by saying the more I look at different lenses, the more confused I become. I'm very new to photography and I really don't understand what all the different lenses do or why there are so many. I upgraded from a Rebel T3 to a Rebel T6i. There is also the T6s, and now I wonder if I should have gotten that instead. It just seemed to be nothing more than gadgety features, so I settled for the T6i. Now I'm kicking myself for that decision.

My main dillema is that lenses can be extremely expensive. I want to take the best possible picture, but now that I've done some research, I'm not so sure that a crop sensor body was a good choice. I'm just really confused about the whole thing. Also, I was considering getting a new STM lens to replace the older 18-55 lense that I've had since I first got the T3. But I don't really understand what an STM zoom lens is either. I only know that it's newer technology. Do I really need to do this? 

My apologies for all the questions, but if anyone can shed some light, is greatly appreciate it.

Thank you in advance.

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Given that you're confused and very new to photography, you probably made the right choice. Full-frame equipment is, on average, much more expensive, and many amateur photographers never find the need to upgrade. There are many excellent crop-frame cameras, and your T6i is one of them.

The selling point for STM lenses is that they're super quiet for use in sound videos. If you don't shoot videos, you may prefer USM lenses. There's more variety, and they tend to focus faster.

[Bill-Emmett]

Canon uses two types of focus motors for their lenses.  USM, which is "ultra sonic" which emitts a noise when focusing, and the newer STM, which means stepping motor.  The STM motor is very quiet when in operation, and was designed for cameras that are used in video production.  Since the mic is located near the lens it would pick up the noise of the USM motor, and you will hear it in the sound track of the video.  

Now, the difference between a full frame sensor, and cropped sensor is really not that important at this point of the game.  But since you asked,  Full frame is the sensor size of 35mm cameras.  The sensor will take the same size photo as the old film cameras.  These senors a usually developed to give a clear picture that can be printed to poster size prints.  Canon cropped frame cameras have a smallar sensor area.  That area is known as the crop factor.  To imagine what this means just take quarter, and place a dime on top, this will give you an idea about the sensor size difference, and the cropped image will be represented by the dime.  The next question will be, how does this effect lenses.  Canon EF lenses are made for full frame cameras, and will present a full frame image to the sensor at all times.   When mounted to a cropped sensor camera, the lens still presents the full frame image, but the sensor will only see the center of the image, and the remaining part of the image will be cropped away.  All Canon lenses use the same crop factor when mounted on Canon cropped sensor camera, which is 1.6.  So, if you multiply the crop factor, to the mili meter value of the lens, the product would give the value of the cropped image.  (50mm lens x 1.6 crop factor=80mm)  So, a 50mm lens mounted to your camera would give the image size of a 80mm lens.  But don't think this is any type of magnification, but only how the crop effects the angle of view of the image.  This effect is the same on zooms, and prime lenses, and EF, and EF-S lenses.  Now, the EF-S lenses are designed to meet the size of the cropped sensor, which is smaller than the full frame sensor,  This image would not cover the entire sensor, and would not produce a very good image.  

Your next question will be about the famous Canon "L" quality lenses.  Canon makes a very high quality lens called "L".  These lenses are made differently than the EF standard lenses.  They are weather sealed to a higher extent, and Canon uses special glass and products inside the lenses.  These lenses are identified by a red ring near the outer end of the lens.  Canon "L" lenses that are considered telephoto are off white in color, instead of black.  These "L" quality lenses will mount to your camera, but the crop factor will be in effect.  If you look, you'll see the cost of these lenses is much higher than the EF, or EF-S lens of the same mm value.  But the image quality with any "L" branded lens will be much better.  

B