# Patent: Canon EF-S 20mm f/2.8 STM



## Canon Rumors Guy (Jun 22, 2015)

```
Another lens patent from Canon, this time for an EF-S 20mm f/2.8. Are we going to see a series of inexpensive EF-S primes in the future? This is pretty close to the 24mm f/2.8 STM pancake though.</p>
<p>Patent Publication No. 2015-111192 (Google Translated)</p>
<ul>
<li>Published 2015.6.18</li>
<li>Filing date 2013.12.6</li>
</ul>
<p>Example 3</p>
<ul>
<li>Focal length 20.65mm</li>
<li>Fno. 2.88</li>
<li>Half angle of view ω = 33.48 °</li>
<li>Image height Y = 13.66mm</li>
<li>Overall length of the lens 64.00mm</li>
<li>BF 35.30mm</li>
</ul>
<p>Canon patents</p>
<ul>
<li>Negative ShiboTadashi</li>
<li>The pay-out the entire</li>
</ul>
<p>We’ve changed how we source things, the source link is at the bottom right of this post if you want to read more.</p>
```


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## SPKoko (Jun 22, 2015)

If you are not selling enough cameras, upsell cheap and nice lenses (10-18, 55-250, 20, 24, 40, 50 STM) to those who have already bought your cameras in the past... Canon sells something to current owners of Canon cameras (most of those people would never buy a >$300 lens anyway) and in addition, they get the users invested in the ecosystem!

Looks like a great strategy to me!


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## Dfunk99 (Jun 22, 2015)

I would prefer to see a nice new *20mm 2.8L *& not an ef-s lens.


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## neuroanatomist (Jun 22, 2015)

Dfunk99 said:


> I would prefer to see a nice new *20mm 2.8L *& not an ef-s lens.



Generally, primes within the range of a zoom need to offer something more than smaller size (faster aperture, macro, tilt/shift). Given the 16-35/2.8, I doubt we'll see a 20/2.8L. Now...a 20mm f/2L, that would be interesting.


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## ajfotofilmagem (Jun 22, 2015)

It seems like a pancake. Maybe I would buy it, but I really just buy a EF-S 20mm F2 or F1.8.
I'm not a big fan of pancakes, but I prefer lenses the same size as Sigma 30mm F1.4 Art.


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## Pixel (Jun 22, 2015)

Hallelujah! I'll be all over it. Perfect compliment to my EF 11-24 f4.


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## Antono Refa (Jun 22, 2015)

neuroanatomist said:


> Dfunk99 said:
> 
> 
> > I would prefer to see a nice new *20mm 2.8L *& not an ef-s lens.
> ...



Or maybe an EF 20mm f/2.8 IS USM


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## Sporgon (Jun 22, 2015)

SPKoko said:


> I you are not selling enough cameras, upsell cheap and nice lenses (10-18, 55-250, 20, 24, 40, 50 STM) to those who have already bought your cameras in the past... Canon sells something to current owners of Canon cameras (most of those people would never buy a >$300 lens anyway) and in addition, they get the users invested in the ecosystem!
> 
> Looks like a great strategy to me!



There must be some accurate logic there, but I'm not surprised that we're seeing Canon finally put out some EF-s prime lenses: they are small, light, high quality, relatively cheap - enough to acquire a few over time without feeling it - and the APS cameras are becoming so good and offer such good value over FF, with the exception of ultra low dof system when they actually become as expensive, I can see why Canon has a growing commitment to the crop camera system. 

The 'crop is dead' brigade are as deluded as the 'Exmor is King' brigade.


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## neuroanatomist (Jun 22, 2015)

Sporgon said:


> The 'crop is dead' brigade are as deluded as the 'Exmor is King' brigade.



The two brigades need to form a united front: Exmor crop sensors cameras will kill Canon FF cameras (in fact, DxO says they already have).


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## wsmith96 (Jun 22, 2015)

I'm surprised they put one so close in focal length to the 24. I would have put one more in the 15/16mm range for a crop camera.


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## verysimplejason (Jun 22, 2015)

Antono Refa said:


> neuroanatomist said:
> 
> 
> > Dfunk99 said:
> ...



Yup. I'd love to have this...


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## Luds34 (Jun 22, 2015)

f/2.8 is a bit slow for a prime. While I personally would welcome some wider, ef-s primes, I'd prefer to see them in the f/2 range (or faster). Otherwise, the only advantage over the many normal zooms out there (from Canon and 3rd party) is size/weight. Possibly IQ as well, however the IQ of the normal zooms are probably "good enough" for that not to be a real factor.

If the 24mm pancake did not already exist, this would be a lot more exciting.


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## mrzero (Jun 22, 2015)

I would have bought this lens when I started in with a crop DSLR. I think the 24mm EF-S pancake is still too long on crop. 20mm works out to 32mm equivalent. However, a fast 14-16 EF-S prime would be spectacular.


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## Khalai (Jun 22, 2015)

neuroanatomist said:


> Dfunk99 said:
> 
> 
> > I would prefer to see a nice new *20mm 2.8L *& not an ef-s lens.
> ...



Perhaps even 20/1.8L to match or better exceed Nikon counterpart  Also while we're at it, I'd love 35/1.2L instead of mk II variant 

There is no thing as "fast enough prime"


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## gunnar997 (Jun 22, 2015)

I own the 20mm 2.8... I shoot 5D3.. 20mm is kind of an awkward focal length on crop cameras.. Just make an IS version for both please! I'd love an IS upgrade on my 20mm.. even better I'd love what everyone else is saying of a 20mm f/2 and even better a 20mm f/2 IS.


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## ashmadux (Jun 22, 2015)

Who would buy this? Probably one of the most boring lens patents in recent memory.

I would LOVE to have the 22/f2 in an EF-s version. That would be spectacular, love that little guy.

Cmon canon..


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## Woody (Jun 22, 2015)

Where is the EF-S 30 mm f/1.4???


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## Khalai (Jun 22, 2015)

Woody said:


> Where is the EF-S 30 mm f/1.4???



Umm, IIRC Sigma has 30/1.4 Art


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## ajfotofilmagem (Jun 22, 2015)

Khalai said:


> Woody said:
> 
> 
> > Where is the EF-S 30 mm f/1.4???
> ...


It's a shame that Sigma 30mm F1.4 Art does not have the same quality optics of 24, 35, 50 Art.


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## casperl (Jun 22, 2015)

ajfotofilmagem said:


> Khalai said:
> 
> 
> > Woody said:
> ...


The 30mm art is pretty good consider its size (not counting the huge hood came with it). I used it for more than a year but just recently upgraded to the 18-35 f1.8. Lovely lens despite the size.


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## 9VIII (Jun 22, 2015)

Right now the 40mm Pancake is probably my favourite lens, it's optically stellar. It's also pretty long for a crop sensor, if they can make a small 20mm lens as good as the 40mm Pancake then this is going to be one of the best crop lenses ever.
I do kind of wish it had IS, but if it's sharp and distortion free like the 40mm was then I'll take it.

I'm pleasantly surprised at the quality of optics Canon is selling in some of their budget lenses. The 40mm Pancake, the new 18-55 STM lenses (especially EF-M), and the 55-250 STM is almost as good as the original 100-400L (250mm on crop is equal to 400mm on full frame, so IQ should be directly comparable).
http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=856&Camera=963&Sample=0&FLI=5&API=1&LensComp=113&CameraComp=453&SampleComp=0&FLIComp=7&APIComp=0


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## preppyak (Jun 22, 2015)

9VIII said:


> Right now the 40mm Pancake is probably my favourite lens, it's optically stellar. It's also pretty long for a crop sensor, *if they can make a small 20mm lens as good as the 40mm Pancake* then this is going to be one of the best crop lenses ever.


Thing is, they basically already did this with the 24mm ef-s lens. Having used both, I cant tell the difference between the two at f/2.8. And I think the 24mm focuses faster.

I agree with others, if this was a 16mm prime to compete with what rokinon/samyang offers, I'd be interested. Or if it was a longer, cheaper ef-s prime (85mm or 100mm) it'd be interesting. At 20mm, it'd have to outperform the 24mm to be able to be priced higher.

Good that Canon is at least patenting EF-S designs though


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## unfocused (Jun 23, 2015)

I'm with the "if it were just a bit wider" crowd. Something closer to a 24-28mm equivalent would be nice. I really don't understand Canon's EF-S prime strategy. 

40 mm f2.8 (okay, I know it's not an EF-S...but.) = 64mm 
24 mm f2.8 EF-S = 45 mm

and now a 20 mm, which would equal 32mm

They just seem like bizarre and not particularly useful focal lengths. 

I'm glad they are doing some EF-S primes, but it seems like they would be a lot more useful if they were a little wider at the wide end and a little longer at the long end.

17-18 mm would get them a nice 28mm equivalent.
60 mm would get you close to a 100mm equivalent.

Together, they'd make a nice set of primes for the SL-2 when it comes out.


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## quiquae (Jun 23, 2015)

unfocused said:


> I'm with the "if it were just a bit wider" crowd. Something closer to a 24-28mm equivalent would be nice. I really don't understand Canon's EF-S prime strategy.
> 
> 40 mm f2.8 (okay, I know it's not an EF-S...but.) = 64mm
> 24 mm f2.8 EF-S = 45 mm



Your math is wrong. 24mm x 1.6 = 38.4mm. It's very close to the 40mm on full frame.



> and now a 20 mm, which would equal 32mm
> 
> They just seem like bizarre and not particularly useful focal lengths.



32mm is fairly close to the 35mm prime focal length, which is a favorite of many. I agree that 64mm equivalent is a weird focal length; 40mm STM is more useful on full frame, I think.



> I'm glad they are doing some EF-S primes, but it seems like they would be a lot more useful if they were a little wider at the wide end and a little longer at the long end.
> 
> 17-18 mm would get them a nice 28mm equivalent.
> 60 mm would get you close to a 100mm equivalent.



EF-S 60mm already exists (f/2.8 macro). 17-18mm probably doesn't exist because it'd be relatively expensive and people wouldn't be inclined to buy expensive EF-S primes.


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## unfocused (Jun 23, 2015)

quiquae said:


> unfocused said:
> 
> 
> > I'm with the "if it were just a bit wider" crowd. Something closer to a 24-28mm equivalent would be nice. I really don't understand Canon's EF-S prime strategy.
> ...



Yeah, I mis-typed I guess.


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## Matthew Saville (Jun 23, 2015)

Why 20mm @ 1.6x? 32mm? This seems to be a little too close to the 24mm EF-S in utility, to be honest.

I'd rather have an 18mm or 15mm EF-S, even if the optics had to be a bit larger and $100-200 more.

Interesting that Canon is doing more new 2.8 primes than any other type. (I started counting new non-L primes with the 24 2.8 EF IS, the 28 2.8 EF IS, the 35 f/2 EF IS, and the 50 1.8 EF STM...)

I'm sure that most folks don't need a lens faster than 2.8, especially casual APS-C shooters, but I would still love to see more fast-but-affordable primes. A redesigned 50 1.4 EF STM and 85 1.8 EF STM are definitely needed, if Canon is going to stop the bleeding to Sigma Art.


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## Maximilian (Jun 23, 2015)

unfocused said:


> I'm with the "if it were just a bit wider" crowd. Something closer to a 24-28mm equivalent would be nice. I really don't understand Canon's EF-S prime strategy.
> 
> 40 mm f2.8 (okay, I know it's not an EF-S...but.) = 64mm
> 24 mm f2.8 EF-S = 45 mm 38mm


I am with you, at least in principle...

Seeing the quality per price ratio of the two pancakes and how they sell (and the supposed profit margin, because they are not "Made in Japan") I can understand Canon trying to continue this success story.

But 64 mm length makes it three times longer than the EF-S24/2.8STM and 1.6 times longer than the EF50/1.8STM.  
EDIT: _I made a mistake here in misunderstanding the patent. It is a pancake, see my post #32_

So definitely not another pancake and for this size 
I would have expected it to be at a FL of 15 to 17 mm but not 20 mm. 

Maybe it's just a "dead" patent that will never get to the market and they decided for the EF-S24/2.8STM instead ... 
(see also filing date 2013.12.6) 8)


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## Antono Refa (Jun 23, 2015)

Dfunk99 said:


> I would prefer to see a nice new *20mm 2.8L* & not an ef-s lens.



Canon has L and non-L versions of the 24mm, 35mm, 50mm, 85mm, 135mm, and 200mm, 300mm, and 400mm lenses.

If Canon made a 20mm f/2.8 non-L over 20 years ago, and never bothered making a 20mm f/1.4L (or even f/2L), I guess it's because Canon knows there's no profit in it.

Then again, if Nikon made a new 20mm f/1.8 lens, maybe it's just a matter of not being as profitable or PRable as other lenses, e.g. the fisheye zoom and 11-24mm, so it just might pop up eventually.


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## Maximilian (Jun 23, 2015)

9VIII said:


> ... if they can make a small 20mm lens as good as the 40mm Pancake then ...


Hi 9VIII! 

As I've noted befor the patent says the lens will be *64 mm long*, so not small and definitely no pancake. 
I don't know if it's possible to make a pancake lens at 20mm or shorter as good the EF-S 24.
But this patent is not that solution.
EDIT: _I made a mistake here in misunderstanding the patent. It is a pancake, see my post #32_


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## insanitybeard (Jun 23, 2015)

Personally, I'd be interested in seeing an ultrawide EF-S prime, say in the region of 10-14mm to give an equivalent full frame focal length of 16-20mm. I've got the 10-22 EF-S and it's a good lens, but having recently bought a 16-35 f4 IS to use as a walkaround on my crop body, a small and compact ultrawide prime would make a nice compliment when 16mm isn't wide enough. I know, I know- I'm probably in a minority here and the focal length is covered by existing EF-S lenses, but if they're making a range of compact EF-S primes, why not an ultrawide?!


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## 9VIII (Jun 23, 2015)

Maximilian said:


> 9VIII said:
> 
> 
> > ... if they can make a small 20mm lens as good as the 40mm Pancake then ...
> ...



Thanks for clarifying that.

It's almost better that this one isn't a pancake. Honestly I was a little disappointed with the 24mm pancake because of the distortion and CA. I know it's not bad compared to most lenses, and especially considering the price, but I was really hoping the characteristics of the first Pancake would carry over to the second. Hopefully as a larger lens a 20mmf2.8 could have better correction (again, not that it's very common to see in that focal length, at any price).
I guess as soon as I start talking about buying multiple inexpensive prime lenses this really is where the Sigma 18-35 comes into its own (which I already have). It is distortion free at 24mm and at 18mm it's the same as the 24mm Pancake, and with the f1.8 aperture it's a no-brainer, except that you're giving up the portability and the freedom of using a $150 lens.


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## neuroanatomist (Jun 23, 2015)

Maximilian said:


> 9VIII said:
> 
> 
> > ... if they can make a small 20mm lens as good as the 40mm Pancake then ...
> ...



If you've noted this before, I must tell you've been wrong on more than one occasion. You're making the (very common) mistake of believing that this is a patent for a lens. Rather, what's being patented is really an _optical formula_ for a lens. So, when the patent states, "Overall length of the lens: 64.00mm," understand that means the length all the way back to the image plane (sensor) as shown in the diagram. Look back at the patent for the EF 40mm f/2.8 (embodiment two), which lists the total length as 62.5mm. 

Once you subtract the flange focal distance of 44mm from the overall length of this 20/2.8 design, you've got a physical lens that's *20 mm long* (actually a bit longer, since filter threads protrude a bit in front of the optical formula). 

So...yes, this is a pancake lens design.


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## Maximilian (Jun 23, 2015)

neuroanatomist said:


> Maximilian said:
> 
> 
> > 9VIII said:
> ...


Thank you for correcting me.

I didn't recognize that before. :-[
My mistake was reading "Overall length of the lens" and "BF" listed up seperately so I understood these two not as beeing BF a part of the lens but to be added up.  So in my wrong conclusion the overall lengh of the optical formula would have been lengh + BF. But that was wrong. Sorry.

*New conclusion:*
If it's indeed another pancake, then the focal lengh is still too close to the EF-S 24mm. 
(Still the question, if it's an alternative or an addition to it)
If it's the shortest FL possible for a pancake with good IQ, then Canon bring it on. 
Otherwise make its FL shorter.


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## TWI by Dustin Abbott (Jun 23, 2015)

neuroanatomist said:


> If you've noted this before, I must tell you've been wrong on more than one occasion. You're making the (very common) mistake of believing that this is a patent for a lens. Rather, what's being patented is really an _optical formula_ for a lens.....



Not only is true, but let me tell you as one that is occasionally privy to inside information from a few companies, some of these patents are actually filed as smokescreens while a slightly different lens (or mount) is being developed.


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## Matthew Saville (Jun 26, 2015)

insanitybeard said:


> Personally, I'd be interested in seeing an ultrawide EF-S prime, say in the region of 10-14mm to give an equivalent full frame focal length of 16-20mm. I've got the 10-22 EF-S and it's a good lens, but having recently bought a 16-35 f4 IS to use as a walkaround on my crop body, a small and compact ultrawide prime would make a nice compliment when 16mm isn't wide enough. I know, I know- I'm probably in a minority here and the focal length is covered by existing EF-S lenses, but if they're making a range of compact EF-S primes, why not an ultrawide?!



If you want high-end lenses dedicated for your crop body, you bought the wrong system.

You should have bought a Ni- ...wait nevermind. They haven't built a high-end DX lens in generations either.

Maybe you should have bought a Pentax? Wait, they don't have anything wider/faster than 12mm f/4, either.

Okay so, buy a Rokinon 10mm f/2.8 or a Tokina 11-20mm f/2.8, and call it a day. Sorry.

But seriously folks, there are in fact tons of great crop-sensor options for ultra-wide zooms, if you're willing to consider third parties. Canon's 10-22 EF-S is no slouch either, for sharpness, in fact despite it falling short of the new 16-35 f/4, it actually beats most copies of the 16-35 2.8 and 17-40. Then there's the Rokinon 10mm f/2.8 if you're really into astro-landscapes, or there's the Tokina 11-16 or 11-20 if you want a zoom but still need 2.8, or there's the Tokina 12-28 if you want the most zoom range possible, and don't need a fast aperture. All of those lenses are so incredibly sharp, they give their full-frame equivalents quite a run for their money. So, unless you're absolutely in need of weather sealing, I'd say you're okay. It is a shame that Canon decided to deliver zero "L" lenses for EF-S, though, that was a corporate tactical error that I think their lens engineers are still shaking their heads over...


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## LonelyBoy (Jun 26, 2015)

Matthew Saville said:


> It is a shame that Canon decided to deliver zero "L" lenses for EF-S, though, that was a corporate tactical error that I think their lens engineers are still shaking their heads over...



I still swear I saw a line from a Canon rep, somewhere, that L means, among other things, it will work on all EOS cameras, so no EF-S L lenses will be produced.

Last time I said this someone brought up a fixed-lens bridge camera with a red ring and L on its lens, which is sort of a side point to a standalone lens.


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## neuroanatomist (Jun 26, 2015)

LonelyBoy said:


> Matthew Saville said:
> 
> 
> > It is a shame that Canon decided to deliver zero "L" lenses for EF-S, though, that was a corporate tactical error that I think their lens engineers are still shaking their heads over...
> ...



There are also the 10x42L IS binoculars.


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## LonelyBoy (Jun 30, 2015)

neuroanatomist said:


> LonelyBoy said:
> 
> 
> > Matthew Saville said:
> ...



Interesting.

I'm still extremely comfortable in saying they'll never make an EF-S L lens.


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