Random curiosity question...why did Canon make the EF-S series of lenses?

[FlipsidE]

So very few cameras can actually use them, and some can be rather expensive. I don't follow why they didn't just make all their lenses EF lenses and all their bodies only accept EF lenses. Was this just an experiment? Or was there some other reason?

Thanks

FlipsidE

[Sprout Crumble]

Technical. It allows greater design freedom in wide-angle lenses to offset the 1.6x crop factor of APS-C sensors and potentially allows lenses to be smaller and lighter.

Happily sits alongside the standard EF mount and IMO will continue to grow in importance though at a slow rate.

[FlipsidE]

Technical. It allows greater design freedom in wide-angle lenses to offset the 1.6x crop factor of APS-C sensors and potentially allows lenses to be smaller and lighter.

Happily sits alongside the standard EF mount and IMO will continue to grow in importance though at a slow rate.I follow what you are saying, but I also find it odd that only what...three cameras can use it. The Rebel, the Rebel XT, and the 20D? It doesn't seem that Canon's filler between the 20D and the 1D can even use them...which I find odd. Seems they just don't really make enough cameras that can use EF-S lenses to support the EF-S line.

FlipsidE

[Scottes]

The reason that larger-frame camera's can't use them is that the size of the mirror is larger on the 1.3x and full-frame bodies and would hit the backside of the lens. Understand that EF-S lenses protrude into the body further than EF lenses, wich works because the 1.6x bodies have smaller sensors and thus smaller mirrors. This is one of the reasons why the lenses are smaller and lighter than EF lenses. (The other reason is the lenses are designed to cover only the 1.6x sensors - they projected image would not hit the corners of a 1.3x sensor, let alone a full-frame.)

In other words, EF-S lenses were made to fit 1.6x DSLRs.

And the reason they "only" fit the Rebels and 20D is because those are ALL THREE of Canon's latest 1.6x bodies.

So it's not very odd at all.

[FlipsidE]

When you consider the number of SLR cameras that support only the EF system versus those that support the EF-S system, it just doesn't seem very lucrative to make lenses that only three bodies can support (maybe 4 if you count the 10D). The 5D, all four models of the 1D, and the numerous film SLR's out there all only support EF lenses. It just seems rather odd that Canon would put time and money into lenses that only four bodies can support.

Maybe I'm just not seeing the big picture, though. But, since the 5D can't support the EF-S system, I begin to wonder if any of Canon's new bodies from here on out will support it. As the prices of sensors come down, the move will definitely be toward full frame. Hence the need for 1.6-only lenses will become less and less until they become completely obsolete...for current generation at that point at least.

FlipsidE

[Tom W]

The reason that larger-frame camera's can't use them is that the size of the mirror is larger on the 1.3x and full-frame bodies and would hit the backside of the lens. Understand that EF-S lenses protrude into the body further than EF lenses, wich works because the 1.6x bodies have smaller sensors and thus smaller mirrors. This is one of the reasons why the lenses are smaller and lighter than EF lenses. (The other reason is the lenses are designed to cover only the 1.6x sensors - they projected image would not hit the corners of a 1.3x sensor, let alone a full-frame.)

In other words, EF-S lenses were made to fit 1.6x DSLRs.

And the reason they "only" fit the Rebels and 20D is because those are ALL THREE of Canon's latest 1.6x bodies.

So it's not very odd at all.

Scottes is right, and I'll add a little.

People will ask why does the lens protrude into the camera more than a standard EF lens? Here's why:

On the Canon EOS mount, the distance from the front flange of the lens mount to the sensor/film plane is 44 mm. One might wonder then, how a camera maker can create a lens with a focal length shorter than 44 mm given that the distance from the rear principal point to the film plane is what defines the focal length of the lens. In ordinary 50 or 85 mm lenses, the principal point resides within the lens. In telephoto designs, it can be in front of the lens, allowing a lens length shorter than the actual focal length. But wide-angle lenses are a different problem requiring a different solution.

There's two parts to the solution. One is the optical design. Wide-angle lenses are designed as an inverted telephoto lens to allow this. The first part of the lens, as the image light rays enter the lens, is essentially a reverse-telephoto lens (Canon refers to it as a negative lens) that sits in front of the main portion of the lens to allow a rear principal point that resides between the rear of the lens and the sensor/film plane. Of course, this approach requires more bending of the light to create an image, and as we bend light more while trying to maintain a rectilinear image, distortion and abberations increase. Generally, the wider the lens, the more bending must occur and thus the more distortion and abberation is introduced to the image.

The other part of the wide-angle solution on regular EF lenses is that the lens protrudes into the camera, a few mm beyond the lensmount flange. The farther into the camera the rear of the lens can protrude, the less alteration or bending of the light must take place before the main lens. But that distance is limited to a couple of mm due to the fact that the mirror is in the way.

But on smaller-sensored cameras, the mirror can be smaller since it doesn't have to project a full-frame image to the focus screen, pentaprism, and eyepiece. It only needs to project the cropped image matching the size of the sensor. So, the mirror can be smaller. And since it is smaller, the lens can protrude deeper into the camera before interfering with the reflex mirror.

The EF-S mount allows a few more mm of lens penetration into the camera body, and thus reduces the required strength of the front retrofocus (reverse-telephoto) lens assembly since the rear of the lens is closer to the rear principal point. But that deeper penetration into the camera would interfere with or damage the mirror in a full-frame camera. So, Canon gave the EF-S a unique mount to prevent use on larger format cameras.

Of course it would have been possible to build a lens within the constraints of the normal EOS-EF mount and still provide the ultra-wide angles. Sigma, Tokina, and Tamron do it. But those lenses are more complex and more prone to abberations and distortion than is the Canon EF-S design. There's a reason that the 10-22 excels in its class.

[rklepper]

I think if you were to look at the big picture of sales overall for the Canon cameras you would find that it is not odd at all as most of their sales are in these cameras.

[Tom W]

When you consider the number of SLR cameras that support only the EF system versus those that support the EF-S system, it just doesn't seem very lucrative to make lenses that only three bodies can support (maybe 4 if you count the 10D). The 5D, all four models of the 1D, and the numerous film SLR's out there all only support EF lenses. It just seems rather odd that Canon would put time and money into lenses that only four bodies can support.

Maybe I'm just not seeing the big picture, though. But, since the 5D can't support the EF-S system, I begin to wonder if any of Canon's new bodies from here on out will support it. As the prices of sensors come down, the move will definitely be toward full frame. Hence the need for 1.6-only lenses will become less and less until they become completely obsolete...for current generation at that point at least.

FlipsidE

The 1.6 sensors aren't going away any time soon. Remember that as full-frame costs drop, so do 1.6-frame costs. So that $500-600 20D-class camera is only a couple of generations away. Yes, full-frame will gain popularity as prices drop, but the 1.6X market is likely to remain strong as those prices drop as well.

I like to think that with the EF-S mount, Canon chose to capitalize on un-used mirror box real estate to produce a superior (even if slightly so) lens. (that almost sounds like marketing :) ).

[woodsie]

I also think that the 1.6 crop bodies are here to stay. I find it invaluable, and I would image that most sports and wildlife photographers would agree, that this body gives my telephoto lenses extra legs, for example making my EF 80-200 f/2.8 L into a 128-320 f/2.8. I challenge you to find lenses equivalent to that on a full sized body.

Full size sensors may get cheaper over time, much to the joy of wedding and studio photographers, but fast telephoto glass will always be expensive.

[EOSAddict]

Check out this parallel thread ;)

http://photography-on-the.net/forum/showthread.php?t=122664

[Scottes]

When you consider the number of SLR cameras that support only the EF system versus those that support the EF-S system...
How many bodies supported EF when it came out? And how many photographers thought EF was junk because it didn't support their old cameras? And where are we now?

Times of forward movement without backwards compatibility will happen.

[tdaugharty]

Seems that over the next few years FF sensors will drop in price thus making the smaller sensor bodies obsolete. Comments?

Frankly to the point of other threads concerning sales figures for the 5D this should "hopefully" drive down cost or at least force cheaper manaufacturing of FF bodies to the prosumer market.

Seems Nikon and others will try to beat or force Canon to produce a 2K price point for FF. All subjective I know but "seems" to make sense to me.

[chuckschilling]

It's clear that Canon developed the EF-S lenses to torture those of you who think that full frame bodies are the be-all, end-all, and that 1.6x crop cameras aren't worth a tinker's damn. Sucks to be you, eh?

[Scottes]

Seems that over the next few years FF sensors will drop in price thus making the smaller sensor bodies obsolete. Comments?
Then we will have even cheaper cameras, yet still have more expensive more.

Digital cameras have existed for years, sensors have always dropped in price, and we still have $8000 cameras available. And you can still purchase a digital camera for less than $100.

[chris clements]

A pedantic question, but I presume the EF-S range will also work on the two APS (film)EOS bodies?
Isn't at least one of the current EF-S lenses just the APS lens of 10/15 years ago dusted down and re-launched?

[uktrailmonster]

When you consider the number of SLR cameras that support only the EF system versus those that support the EF-S system, it just doesn't seem very lucrative to make lenses that only three bodies can support (maybe 4 if you count the 10D). The 5D, all four models of the 1D, and the numerous film SLR's out there all only support EF lenses. It just seems rather odd that Canon would put time and money into lenses that only four bodies can support.

Maybe I'm just not seeing the big picture, though. But, since the 5D can't support the EF-S system, I begin to wonder if any of Canon's new bodies from here on out will support it. As the prices of sensors come down, the move will definitely be toward full frame. Hence the need for 1.6-only lenses will become less and less until they become completely obsolete...for current generation at that point at least.

FlipsidE

Only 3 bodies at the moment (all high volume prosumer cameras), but all future Canon cameras that use 1.6 crop sensors will support EF-S. They have no place on full frame cameras like the 5D and 1Ds

[Jon]

A pedantic question, but I presume the EF-S range will also work on the two APS (film)EOS bodies?
Isn't at least one of the current EF-S lenses just the APS lens of 10/15 years ago dusted down and re-launched?
No. The mount is physically different from the EF mount. EF-S mounts won't fit on cameras that don't have the EF-S body mount, and to date only 3 cameras (300D,350D, 20D) have it.

[Tom W]

A pedantic question, but I presume the EF-S range will also work on the two APS (film)EOS bodies?
Isn't at least one of the current EF-S lenses just the APS lens of 10/15 years ago dusted down and re-launched?

I believe that the 24-85 f/3.5-4.5 USM was launched as an APS lens, but fully compatible with full-frame. It never got dusted off, but has remained in production. I believe it was featured on the 10D in at least one or two of the brochures.

I wonder if the APS film cameras of the future couldn't be adapted to the EF-S format. I don't know the exact dimensions of the format so I don't know if the image circle matches or not. As well, I don't expect that APS film camera sales are very high. It is truly not a popular format, especially when 35 mm can be had for the same price.

[chris clements]

I believe that the 24-85 f/3.5-4.5 USM was launched as an APS lens.
Thanks, Tom. This is probably the lens I'm remembering. Touching that you talk about the APS format in the present tense, but I have long accepted that my IX body is just a museum piece.

Back on topic, I add my vote of support for EF-S lenses (and x1.5/1.6 optimised lenses in general) as the future rather than a dead end.
For the new digital generation growing up without 35mm memories there's no mystique to full frame. And no-one but a pro will ever really need more than 10-15 mp, which technology can/will acheive comfortably on APS-sized sensors with the accompanying savings on size and cost.

[Tom W]

Thanks, Tom. This is probably the lens I'm remembering. Touching that you talk about the APS format in the present tense, but I have long accepted that my IX body is just a museum piece.

Back on topic, I add my vote of support for EF-S lenses (and x1.5/1.6 optimised lenses in general) as the future rather than a dead end.
For the new digital generation growing up without 35mm memories there's no mystique to full frame. And no-one but a pro will ever really need more than 10-15 mp, which technology can/will acheive comfortably on APS-sized sensors with the accompanying savings on size and cost.


I tend to see both full-frame and 1.6X surviving in the long haul. Both have their strengths and weaknesses, and having a choice is important. I like what full-frame has to offer, but YMMV. Anyway, It's nice that there can be lenses that take advantage of the smaller format by allowing a closer lens-to-sensor distance. And, it's also nice to see some cross-compatibility in the system. Where else can you find lenses that work automatically in two different formats?

[ScottE]

Why did Canon make EF-S lenses? Because the rear lens element is closer to the image plane so that it is possible to use a less radical retro-focus design for short focal length lenses. This allows higher quality lenses because light does not have to manipulated as much.

Why don't EF-S lenses fit D30, D60 (damn, I still have mine) and 10D cameras? Because those cameras were designed before the EF-S lenses were designed. That doesn't mean Canon shouldn't design a better system for future cameras. Canon has a history of moving forward with new lens systems to meet future needs such as the EF system designed for an electronic camera/lens interface or the EF-S system designed for APS sized sensors. This allows them to concentrate on designing lenses that are best for a specific purpose and not have to worry about accommodating legacy cameras. Nikon has taken a different approach and all their lenses are still based on their old mechanical 35 mm film mount. This means they have to design around the limitations of that mount and many older lenses that will fit modern bodies are not fully functional.

[LightRules]

Ahh no worries, just convert it to EF mount in 3 minutes, use the 24-85mm USM rear baffle, and you're 10D-ready: http://www.pbase.com/fstopjojo/efconv :)

[Tom W]

Ahh no worries, just convert it to EF mount in 3 minutes, use the 24-85mm USM rear baffle, and you're 10D-ready: http://www.pbase.com/fstopjojo/efconv :)

I'm not sure I'd try that with the 10-22 though. :)
Or at least I'd let someone else do it first.

[LightRules]

I'm not sure I'd try that with the 10-22 though. :)
Or at least I'd let someone else do it first.

Come on Tom, you know you want to be the guinea pig! :lol:

[Tom W]

Come on Tom, you know you want to be the guinea pig! :lol:

I'll just defish my fisheye, thanks. :)

Really, I think that the rear lens element of the 10-22 is the closest to being vulnerable of all the EF-S lenses to date, so anybody that wants to do this really needs to do some careful measuring first.

[mijbril]

The 350D was one of the hottest selling cameras of 2005. Just think of all those kit lenses out there....

1.6 & EF-S, it's here to stay

[usukshooter]

t's clear that Canon developed the EF-S lenses to torture those of you who think that full frame bodies are the be-all, end-all, and that 1.6x crop cameras aren't worth a tinker's damn. Sucks to be you, eh?

Not really. I love my 20D to bits, of course it's worth a "tinkers damn" but I learned on film and I guess I just think the sensor in a 35mm digital camera should be the same size as a 35mm film negative so that they act the same way in terms of DOF, focal length, perspective, etc. Eventually. Right now, I'm perfectly happy with my 20D until I can afford a full frame DSLR and obviously the EF-S line has benefits for both Canon and the consumers who don't plan to upgrade.

My fear is that one day they'll be able to sell full frame DSLRs for the same price of 1.6x DSLRs, even if the DSLRs with smaller sensors go down to a really low price like $300 USD, but because of the EF-S line, Canon will continue to charge more for the full frame DSLRs and force buyers to pay more then they should just to get a camera that acts the way a 35mm SLR should. Sure, it may not happen for a long time but I worry that eventually it will and because I'm still fairly young, it will probably be in my life time.

[jojohohanon]

Speaking of defished fisheyes,

can anyone who does this often post some samples? Best would be if you have a 10-22 and a fisheye to compare. I've seen a couple of defished images, and it seemed to me that the edges really suffered, but I never had a rectilear to compare against.

[FlyingPete]

Seems that over the next few years FF sensors will drop in price thus making the smaller sensor bodies obsolete. Comments?


A discussion I had with a Canon Camera employee back in July indicated that it is Canon's intention to move all DSLR's to full frame over time, the question is, what is that time frame?

For the time being it seems that fabrication of such large sensors (Full Frame) is very costly, too make a sensor 4 times the area of another sensor is more than 4 times the cost due the actual number of sensors that can be fitted on a wafer and the yield rates being lower for larger chip sizes.

Most of the difference in cost to produce a 20D and 5D is probably in the sensor.

[MrChad]

What is this only 3 SLR bodies stuff? I don't think sales volumes of D30/60/10D combined can't even come close to the number of 300D's (Digital Rebels) sold. Factor in I may soon have more buddies with 350D's then original Rebel-D's and you have plenty of reasons to develope a new lens system for the APS-C sensor.

A kit with a 10-22mm; 17-85mm IS; and any one of the many awesome Canon Tele-zoom EF's lenses would be a stellar kit.

[Tom W]

Speaking of defished fisheyes,

can anyone who does this often post some samples? Best would be if you have a 10-22 and a fisheye to compare. I've seen a couple of defished images, and it seemed to me that the edges really suffered, but I never had a rectilear to compare against.

OK, here's a bit of de-fishing. The shot was taken with the 1D II, so it's a bit more "fishy" than it would be on a 20D or XT, but not as fishy as on a 5D.

Here's the original:

http://www.pbase.com/photosbytom/image/54055710.jpg

After some de-fishing with PTLens plugin in Photoshop ELements 3:

http://www.pbase.com/photosbytom/image/54055711.jpg

I can't compare it to the 10-22, though. Word is that a de-fished 15 mm fisheye has a field of view similar to a 12 or 13 mm rectilinear lens.

[tdaugharty]

Quite to the contrary ... I love my 20D along with L/EX glass and it takes in images far better than any of the Sony equipment used before. I paid $1600 bucks for a loaded Mavica 2MP CD1000 that could burn to a CD and unless I shot TIFF it produced really crappy pictures however it was cool at parties ;)

Now on the other hand my first real camera experience was my Dad's Pentax 35mm and after shooting with it going to a cropped frame takes getting used to. So using a FF digital has it's advantages. No FOV crop, True super wide angle, Lower frame noise, Shallower DOF.

Certainly advantages to smaller sensors which google can provide so it does come down to preference. So IMO FF digital at a consumer price would just enable me to use a little "old school" tact without having to break out a calculator to translate.

It's clear that Canon developed the EF-S lenses to torture those of you who think that full frame bodies are the be-all, end-all, and that 1.6x crop cameras aren't worth a tinker's damn. Sucks to be you, eh?

[scokar]

OK, here's a bit of de-fishing. The shot was taken with the 1D II, so it's a bit more "fishy" than it would be on a 20D or XT, but not as fishy as on a 5D.

Here's the original:[...]

I was expecting the aquarium to be empty :)

[jojohohanon]

Hey, Tom, thanks!

Hard to judge sharpness from save-for-web pix, but it does seem that some corner sharpness is lost by the defishing.

(as for Scokar: waka waka waka!)

[Tom W]

Hey, Tom, thanks!

Hard to judge sharpness from save-for-web pix, but it does seem that some corner sharpness is lost by the defishing.

(as for Scokar: waka waka waka!)

Yes, you will undoubtedly lose a little corner resolution as things are stretched and squeezed to make the image rectilinear (much like what a normal wide angle lens has to do), but it is useful for prints of reasonable size.

I have to say though that the fisheye is extremely wide on full-frame. It sees a full 180 degrees from corner to corner.

[Longwatcher]

Way back in the long ago days of D60 and 10D cameras there was a need for a wide angle capability. Noting this and the large growth in APS-C priced DSLR's Canon decided to create the EF-s lens series. Because of reasons mentioned before to make a proper wide angle for the APS-C sensor you had to move the back of the lens too close to the sensor plane and thus to avoid absent minded people like me forgetting that the mirror will connect with the lens if used on a FF camera, Canon decide to give it a distinct mount. Unfortunately the D60 and 10D came out before EF-s was available so too late to back fit.

Now Canon probably figures that they would be producing APS-C sized sensors for at least 7-10 years (2 of which have gone by already) and were nice enough to produce some wide angle lenses to go with the APS-C sensor. Thus giving us wide angle capabilities again.

My logic seems to be valid based on the fact that I know of no EF-s lens longer then 85mm and then only a zoom. The true anomoly to my theory appears to be the 60mm macro, which I am sure there is a valid need for that lens with APS-C sensors.
I expect few if any additional lenses to come out in the EF-s line and will really be surprised if they ever come out with an EF-s lens longer then 100mm (highly surprised if more then 200mm).

So with at least 5 years left of APS-C production that is a fairly long life for most people's camera before they would upgrade anyway.

And as to the market. consider if you will the number of 300D/350D versus 10D/20D versus the 5D and 1D sales. and the following is a guess, but I would guess for every 100,000 300D/350D sold; 10,000 10D/20D were sold and about 100 1D series. So there are 110,000 people out there who need wide angle lenses and 100 who have them. Looks like market demand to me.

just my opinion,

[suryad]

I just want to see some L glass released for EF-s models.

[Mark_Cohran]

I just want to see some L glass released for EF-s models.
I suppose it's possible, but I suspect it's highly unlikely.

Mark

[MrChad]

I just want to see some L glass released for EF-s models.

I agree a 10(12)-24mm f2.8L would be a delightful optic IMO. Seeing that I can create full frame 20"x30" prints from my 300D I'm not sure that I would ever need FF save for the want of a weather sealed body and all the goodies the newer models have but my photos won't get much better with newer gear. As long as Canon makes APS-C DSLR more affordable I'll likely stick with them.

That said I doubt a weather sealed APS-C Canon would ever debut, thus the need for an L wide angle EF-S is unlikely. And unless they make an 22-70mm f2.8(EF-S) a heck of alot lighter/smaller then my 24-70 f2.8L I don't see the need for that either.

I don't think too many more EF-S will debut either unless they refine the focal lengths already made or debut another prime lens, like a 30mm f1.4 to compete against the Sigma model already out. I might spring for one of those one day.