# Lens design comparison: Canon EF 50mm f/1.8 STM and the Canon RF 50mm f/1.8 STM



## Canon Rumors Guy (Oct 30, 2020)

> Here is a lens diagram comparison between the EF 50mm f/1.8 STM and the upcoming Canon RF 50mm f/1.8.  The new RF 50mm f/1.8 STM definitely looks like a brand new lens design and not simply making the EF mount version work with RF, which likely would never be worth the time and effort anyway.
> As pointed out by forum contributor privatebydesign, this is a “double-gauss” lens design.
> I expect to see this lens announced next week, if not sooner.



Continue reading...


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## H. Jones (Oct 30, 2020)

Very similar, same number of elements, but definitely different. I doubt this will cost much more than the EF 50mm, if not the same amount. 

It does seem like it at least takes advantage of the new mount by enlarging the rear-most element, so hopefully that in itself can improve IQ a bit. I'll be interested to see how it turns out. 

It's tough to tell, the diagrams aren't to scale, but looking at the rear mount bit, it does seem like the RF lens is slightly smaller, which is a big perk when you consider it's going on the R cameras without an adapter and will make a very small end result.


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## Andy Westwood (Oct 30, 2020)

Sooner the better! it will be interesting to know the price, dimensions, and weight of this little cutie! And to get some early feedback on performance.


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## Canon Rumors Guy (Oct 30, 2020)

I go back and forth between $149 and $199, the control ring may add a bit of cost.


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## heysavnac (Oct 30, 2020)

I was about to purchase a control ring adaptor and an EF 50mm 1.8, I’m so glad I waited! I assume it will be a price of $299, but most comments are mentioning a 149 to 249 price tag, and I’m hoping that’s the case. If it’s that cheap. I’m definitely buying this one, even if I have the RF 35 and 85, just because of its price, and size.


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## privatebydesign (Oct 30, 2020)

It is just the standard Double-Gauss design that has been around in innumerable formulae's since 1817.









Double-Gauss lens - Wikipedia







en.wikipedia.org





Uncle Roger has a great series of articles on optical designs too.









Lens Genealogy Part 1


In which I begin to answer the question "Why Do You Put the Lens Diagrams on Your Website?" Where do new lens designs come from? I knew that today's lenses are all designed using computer programs, but I was surprised to find new lenses aren't designed from scratch. Designers start with an...



www.lensrentals.com





What I actually find interesting is the element offset, the RF lens elements are set further forwards than the EF version and are an effective 'adapter', they are not using the advantages of the shorter flange distance here one bit, merely rejigging the thing to do the same. I'd expect performance to be somewhere between the EF 1.8 and EF 1.4, the key will be the way they have used the special element in green.


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## marathonman (Oct 30, 2020)

First response ******* posts are *******!


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## hunck (Oct 30, 2020)

Canon Rumors Guy said:


> I go back and forth between $149 and $199, the control ring may add a bit of cost.



The Nikon Z50 f/1.8 lens is some 600 euro... I agree, they market that one different, but still, it gives Canon an opportunity to ask 349,- for the RF50 f/1.8. Why not? I'll buy it.


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## slclick (Oct 30, 2020)

Canon is Domed!


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## Aaron D (Oct 30, 2020)

New optics are good. I'm more like to get than I was a couple hours ago.

And how does Nikon have to make theirs twice as big? I don't get it.


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## Skux (Oct 30, 2020)

They just moved the elements further down the barrel lol


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## Mt Spokane Photography (Oct 30, 2020)

I expect design and pricing to be similar to the RF 35mm f/1.8. It is certainly possible that it will be a cheap kit lens but most low end camera buyers want a zoom.


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## quiquae (Oct 30, 2020)

privatebydesign said:


> It is just the standard Double-Gauss design that has been around in innumerable formulae's since 1817.
> 
> 
> 
> ...


They are definitely taking advantage of the shorter back flange distance. Assuming that the diagrams are actually to scale, the RF version has a back flange distance of something like 30mm (20mm behind the lens and ~10mm inside the lens), whereas the EF mount has a minimum of 44mm.


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## EOS 4 Life (Oct 30, 2020)

Mt Spokane Photography said:


> I expect design and pricing to be similar to the RF 35mm f/1.8. It is certainly possible that it will be a cheap kit lens but most low end camera buyers want a zoom.


Lenses like these tend to be in a bundle instead of a zoom.
I would not rule out an f/1.8 bundle as a kit.


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## syder (Oct 30, 2020)

SwissFrank said:


> It's such an important focal length that I'd like them to make two: one with portability being first priority (should stick out no further than the front of the grip) and the other being image quality as first priority, like the Leica APO 50/2. Even if it's $3000 for 50/1.8, and huge, why not do it just as a halo product.



The RF 50 1.2 is the high quality 50mm rf prime. This will be the cheap & small one.


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## Maximilian (Oct 30, 2020)

I am glad to see that Canon is trying to improve the optical formula, even though they stay with double Gauss design. 
I am sure it is for a more cost effective production, maybe simpler mechanical parts and more automated assembly.
I hope the improvement is also for better IQ.

And I hope there will be a 50 mm lens with IS and better optics between this and the RF50L.


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## Maximilian (Oct 30, 2020)

Skux said:


> They just moved the elements further down the barrel lol


Not only that.
The basic double Gauss design stayed the same.
But I see different gaps between the elements.
And I see elements cut on both sides where one was only cut on one side (two working steps = more expensive).
And as the rear element seems to be bigger the exit pupil seems to be bigger, too.
= less refracting of the light rays in that last element = maybe less CA (but just guessing)

This is an at least much modifyed optical formula, if not totally redesigned (still based on the same double Gauss design).

_Edit: and you don't see just from this drawing if they maybe added some new and better coatings._


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## Antono Refa (Oct 30, 2020)

syder said:


> The RF 50 1.2 is the high quality 50mm rf prime. This will be the cheap & small one.



RF 50mm f/1.2L USM is priced $2,300, about the same as the EF 70-200mm f/2.8L IS III USM @ $2,100

The RF 50mm f/1.8 STM will be priced say $300, 2.5x the price of the EF 50mm f/1.8 STM

Do you really think there's no place for an RF 50mm f/1.4 IS USM at $600 in between?

_______________________________________________________________________________________________________

Added in editing: Nikon, Sony, Sigma, and Zeiss all have a 50mm f/1.4 priced $1,000-$1,500. IIRC, someone wrote all those lenses are expensive pickle jars because the only way to make them fast & high IQ was a reverse telephoto design.

The RF mount cut the flange distance from 44mm to 20mm. Shouldn't that open the door for Canon to make a 50mm f/1.4 that combines the cheap double Gauss design with the high IQ of the above mentioned lenses? Is the RF 50mm f/1.8 it? Really no place for sub-$1K 50mm f/1.4 IS?


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## Sharlin (Oct 30, 2020)

Oh, so it was not the 7-element design found by canonnews after all. Interesting.


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## Ziz (Oct 30, 2020)

Antono Refa said:


> RF 50mm f/1.2L USM is priced $2,300, about the same as the EF 70-200mm f/2.8L IS III USM @ $2,100
> 
> The RF 50mm f/1.8 STM will be priced say $300, 2.5x the price of the EF 50mm f/1.8 STM
> 
> Do you really think there's no place for an RF 50mm f/1.4 IS USM at $600 in between?


A 50 1.4 IS USM that is even smaller than the EF version would be taking pride of place on my camera 90% of the time.


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## mb66energy (Oct 30, 2020)

Am I the only one who has seen the greenish lens (5th from left)? This is an ASPHERICAL LENS in canon.jp - color terminology. If this lens diagram is correct, this lens might be MUCH better than the older EF 1.8 iterations at least wide open.

My guess is 200 $ / € because aspherical lenses are found in cheap zooms today, 200 is a nice number and it has NO IS, NO control ring (like RF 24-240) and presumably NO macro function. An additional argument: It might be a good companion to a "below EOS RP" camera?!

And 24-240 + this one would make a good entry kit, 24-240 for the day, 1.8 50 for the "night" ...


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## Joules (Oct 30, 2020)

mb66energy said:


> Am I the only one who has seen the greenish lens (5th from left)? This is an ASPHERICAL LENS in canon.jp - color terminology.


Thanks for looking it up. I wasn't sure anymore if that color really meant aspherical. Nice to see that in there. I suspect this design will beat the pants of the old one. It also looks really nice in terms of build quality. 

Also, this lens does have a control ring, it just doubles as the MF ring. So MF is one of the options you can control with it, and you toggle it with the switch in the lens.


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## syder (Oct 30, 2020)

Antono Refa said:


> RF 50mm f/1.2L USM is priced $2,300, about the same as the EF 70-200mm f/2.8L IS III USM @ $2,100
> 
> The RF 50mm f/1.8 STM will be priced say $300, 2.5x the price of the EF 50mm f/1.8 STM
> 
> ...



I was responding to a specific claim that canon should have 2 different 50mm lenses...

But also no. Combining a cheap double gauss design with the price and iq of a $1k non double Gauss design isn't likely. There's a clear design choice between a cheap and simple lens and a more complex, larger and more expensive lens. 

Could canon make something like a slightly smaller sigma art 50 f1.4 for the RF mount, probably. But there are almost certainly a huge number of RF lenses they'll prioritize before making a 3rd RF 50mm.


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## MayaTlab (Oct 30, 2020)

Aaron D said:


> And how does Nikon have to make theirs twice as big? I don't get it.



It's a much more ambitious design, that's all (no focus breathing, fairly flat field with very low field dependent aberrations, internal AF, etc.). 

This Canon lens is meant to be (very) cheap and cheerful. So a completely different target.


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## Ale_F (Oct 30, 2020)

Gauss design is not negative. For a cheap lens is the best.
Remember that only Leica has the 50mm 0.95 Gauss version for FF (Noctilux). All others manufacturers used reverse telephoto design.


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## blackcoffee17 (Oct 30, 2020)

Aaron D said:


> New optics are good. I'm more like to get than I was a couple hours ago.
> 
> And how does Nikon have to make theirs twice as big? I don't get it.



The Nikon lens is a very high performance lens, at the level of Canons 1.2, except the aperture.


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## Greywind (Oct 30, 2020)

Aaron D said:


> New optics are good. I'm more like to get than I was a couple hours ago.
> 
> And how does Nikon have to make theirs twice as big? I don't get it.


That Z mount 50mm 1.8 is one of the sharpest 50mm, therefore the price.


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## Mistral75 (Oct 30, 2020)

Both the EF 50mm f/1.8 STM and RF 50mm f/1.8 STM are Planar derivatives.

The EF version has an Ultron design (split front doublet) whilst the RF one has a Pancolar design (split rear doublet).


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## Steve Balcombe (Oct 30, 2020)

mb66energy said:


> Am I the only one who has seen the greenish lens (5th from left)? This is an ASPHERICAL LENS in canon.jp - color terminology. If this lens diagram is correct, this lens might be MUCH better than the older EF 1.8 iterations at least wide open.
> 
> My guess is 200 $ / € because aspherical lenses are found in cheap zooms today,


I'm pretty sure the aspherical lens in the old EF-S 18-55 kit lens was plastic, which Canon didn't actively promote because quite honestly the idea of a plastic element doesn't come across well! Maybe this will be the same. I think it was stated in an early press release, but marketing material just describes it as "aspherical". If it works, who cares?!


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## peters (Oct 30, 2020)

Canon Rumors Guy said:


> I go back and forth between $149 and $199, the control ring may add a bit of cost.


I think its more likely on the higher end, maybe 180 USD. Maybe 220€ with tax here in europe. 
I think it is a lense for the masses, but the sexy control ring and the small form factor that you get combined with an R camera is something that will make the lense more interesting.
I hope for 150 USD though :-D


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## sulla (Oct 30, 2020)

This green lens is something special the EF version doesn't have. If it is an aspherical element, image quality could improve greatly, and as we can see from the EF 40, moulded aspherical elements are not really expensive to make. If it is "only" a low dispersion element or something like this, chromatic aberrations (and not so much sharpness) could improve. Either way, the RF lens looks to be more sophisticated than the EF one. Looks good to me.


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## Sporgon (Oct 30, 2020)

Mistral75 said:


> Both the EF 50mm f/1.8 STM and RF 50mm f/1.8 STM are Planar derivatives.
> 
> The EF version has an Ultron design (split front doublet) whilst the RF one has a Pancolar design (split rear doublet).


Looking at that I'd expect this RF lens to probably be very sharp at the expense of subject separation / bokeh.


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## Fran Decatta (Oct 30, 2020)

Antono Refa said:


> RF 50mm f/1.2L USM is priced $2,300, about the same as the EF 70-200mm f/2.8L IS III USM @ $2,100
> 
> The RF 50mm f/1.8 STM will be priced say $300, 2.5x the price of the EF 50mm f/1.8 STM
> 
> ...




For sure that there's a place for a 50 1.4 (IS or not) butI bet that would cost more than 1200€ if its well made with nice IQ and AF system. If a new designed 50 1.4 costs 600€ the price gap between 1.2 and 1.4 would make not deserve to pay that difference to have that 1.2.


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## Antono Refa (Oct 30, 2020)

Aaron D said:


> And how does Nikon have to make theirs twice as big? I don't get it.



Its a completely different design, with 12 elements, of which 2 are aspherical and 1 ED.


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## slclick (Oct 30, 2020)

OK, who's got the diagram with the DG vs reverse tele designs handy? Pickle jars vs compact. Anyone?


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## Absolutic (Oct 30, 2020)

I hope it is a different design from 50 1.8 STM, I have 50 1.8STM and I don't think it is great on my R5...... at least it is the weakest lens optically wide open on R5 out of all the ones I have. I hope they change design to make it better. I will def get one. As for pricing, who knows. Nikon Z 50 1.8 is a superb lens but $600. Sony 50 1.8 E is not a great lens but cheap ($250). I assume Canon one will be somewhere in between $249 and 600, maybe something like $399.


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## slclick (Oct 30, 2020)

Absolutic said:


> I hope it is a different design from 50 1.8 STM, I have 50 1.8STM and I don't think it is great on my R5...... at least it is the weakest lens optically wide open on R5 out of all the ones I have. I hope they change design to make it better. I will def get one. As for pricing, who knows. Nikon Z 50 1.8 is a superb lens but $600. Sony 50 1.8 E is not a great lens but cheap ($250). I assume Canon one will be somewhere in between $249 and 600, maybe something like $399.


The design in right there for us to see. Similar yet not the same as the EF counterpart. I'm not sure why this is a mystery to some, it will be good not great. Regardless, it will be welcome by many, especially those who want and need more choices. More is better.


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## Absolutic (Oct 30, 2020)

slclick said:


> The design in right there for us to see. Similar yet not the same as the EF counterpart. I'm not sure why this is a mystery to some, it will be good not great. Regardless, it will be welcome by many, especially those who want and need more choices. More is better.



I consider 35 1.8 RF great on R5. hope 50 1.8 RF is close, that's all I am hoping for


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## privatebydesign (Oct 30, 2020)

Sporgon said:


> Looking at that I'd expect this RF lens to probably be very sharp at the expense of subject separation / bokeh.


That is definitely the trend nowadays!


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## canonnews (Oct 30, 2020)

Canon Rumors Guy said:


> I go back and forth between $149 and $199, the control ring may add a bit of cost.


I'm going with $199 to $249.

RF mount tax


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## canonnews (Oct 30, 2020)

Absolutic said:


> I consider 35 1.8 RF great on R5. hope 50 1.8 RF is close, that's all I am hoping for


I wouldn't expect it as good as the RF 35mm.
I think people have to measure their expectations a bit. it's a pretty simple design. it's going to have it's flaws wide open.

you don't usually get small, cheap and optically great all in one package.

you get two of the three.


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## mb66energy (Oct 30, 2020)

privatebydesign said:


> [...]
> 
> What I actually find interesting is the element offset, the RF lens elements are set further forwards than the EF version and are an effective 'adapter', they are _*not using the advantages of the shorter flange distance*_ here one bit, merely rejigging the thing to do the same. I'd expect performance to be somewhere between the EF 1.8 and EF 1.4, the key will be the way they have used the *special element in green*.



I think that making a shorter 50mm leads to flatter angels of the light reaching the sensor and increases


Steve Balcombe said:


> I'm pretty sure the aspherical lens in the old EF-S 18-55 kit lens was plastic, which Canon didn't actively promote because quite honestly the idea of a plastic element doesn't come across well! Maybe this will be the same. I think it was stated in an early press release, but marketing material just describes it as "aspherical". If it works, who cares?!



I think so, it is much easier to mould. My glasses have too plastic lenses and they are optically very good - only contrast suffers after cleaning them several times compared to glass lenses - but the lens element in the RF 50 is not exposed so I think you are right: No problem here.


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## [email protected] (Oct 30, 2020)

Steve Balcombe said:


> I'm pretty sure the aspherical lens in the old EF-S 18-55 kit lens was plastic, which Canon didn't actively promote because quite honestly the idea of a plastic element doesn't come across well! Maybe this will be the same. I think it was stated in an early press release, but marketing material just describes it as "aspherical". If it works, who cares?!



2 things:
1) The "blue goo" tech that Canon put it some of its very best lenses, like the 35mm f/1.4 L II is essentially a plastic element. They cleverly call it an "organic optical compound," which essentially is code for plastic. I can't say anything bad about it, as the lenses in which it's been used have been amazing. The person who started the "blue goo" term was doing so to poke fun at their wording, referencing a Dr. Seuss book Fox in Sox.
2) The quality of the EF 50mm f/1.8 was excellent, but the autofocus consistency was pretty bad. People's unsharp results weren't due to the optical formula. The new design will likely be a small improvement relative to coatings improvements and (hopefully) a more reasonable focus registration.


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## gruhl28 (Oct 30, 2020)

Does anyone else find it odd that Canon makes "medium" quality and aperture lenses with IS in moderate wide angle (35mm RF, 24mm, 28mm, and 35 mm EF) and moderate telephoto focal lengths (85mm RF), but in the "standard" 50 mm they only make very high end and low end without IS? This was true in EF, and now it's the case with RF as well.

I'm actually surprised I haven't seen anyone complaining yet that this lens doesn't have IS. There is still no standard focal length prime lens from Canon with IS. Why?


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## privatebydesign (Oct 30, 2020)

gruhl28 said:


> Does anyone else find it odd that Canon makes "medium" quality and aperture lenses with IS in moderate wide angle (35mm RF, 24mm, 28mm, and 35 mm EF) and moderate telephoto focal lengths (85mm RF), but in the "standard" 50 mm they only make very high end and low end without IS? This was true in EF, and now it's the case with RF as well.
> 
> I'm actually surprised I haven't seen anyone complaining yet that this lens doesn't have IS. There is still no standard focal length prime lens from Canon with IS. Why?


Because the market isn’t there anymore. The concept of a ‘standard prime’ can be defined as a niche, that niche can be fairly subdivided into people new to the medium who are told over and over again “you need to get a nifty fifty” and committed amateurs and pros who actually love and use the focal length. The first group buy the cheap option the second either buy or aspire to the second,. The number of undecideds in between is a subgroup within a niche within a niche and from a corporate point of view simply not large enough to cater to.


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## RMac (Oct 30, 2020)

With an aspherical element and the fact that it's RF I'd wager a release price between $200-300. Hopefully it gets a nice boost in wide-open sharpness compared to the ef

This will yield a super-compact camera+lens!


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## Aaron D (Oct 30, 2020)

Antono Refa said:


> Its a completely different design, with 12 elements, of which 2 are aspherical and 1 ED.


They go to such lengths for sharpness; not compactness, not economy. And I'm sure it is a sharper lens, but the cheap old EF 50 is still one ofCanon's sharpest lenses...


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## gruhl28 (Oct 30, 2020)

privatebydesign said:


> Because the market isn’t there anymore. The concept of a ‘standard prime’ can be defined as a niche, that niche can be fairly subdivided into people new to the medium who are told over and over again “you need to get a nifty fifty” and committed amateurs and pros who actually love and use the focal length. The first group buy the cheap option the second either buy or aspire to the second,. The number of undecideds in between is a subgroup within a niche within a niche and from a corporate point of view simply not large enough to cater to.


I understand what you're saying, but is 50mm more of a niche than 35mm or 85mm (or 24 or 28 in EF)? You could say that every prime focal length is a niche, couldn't you?


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## mangobutter (Oct 30, 2020)

It's almost as if this (seemingly) double-gauss design was largely lifted from the EF version, tweaked with a replaced asph element, and the entire lens group was shifted forward to keep a similar distance to the sensor as it would with the SLR version. I imagine this to be better optically than the EF version--it has to... so my guess is it will be sharper wide open but I think that extra/added/replaced element in green is going to cause some slightly harsh bokeh (relative to the EF version) or at least be similar or same.

So in other words this will be a great value buy but don't expect image quality miracles. It'll be sharp and practical, but i dont think the rendering and softness quality will be blowing anyone away.

I'll still buy it just because =) $149 seems appropriate for such a lens.

Now Canon, can you replicate the 40mm pancake a la EF? =)


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## mangobutter (Oct 30, 2020)

canonnews said:


> I'm going with $199 to $249.
> 
> RF mount tax



On one hand I want to say $199 but that would prevent Canon from making this lens make headlines and gain people into the RF system. I think this lens has to be Canon's RF gateway drug to entice over SLR users. $199 limits how "big" this lens can get


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## privatebydesign (Oct 30, 2020)

gruhl28 said:


> I understand what you're saying, but is 50mm more of a niche than 35mm or 85mm (or 24 or 28 in EF)? You could say that every prime focal length is a niche, couldn't you?


Yes, and it is, and it is a shrinking niche which bodes poorly for more options. I do not believe the RF line will ever have the depth and range the EF line had.


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## SUNDOG04 (Oct 30, 2020)

Aaron D said:


> New optics are good. I'm more like to get than I was a couple hours ago.
> 
> And how does Nikon have to make theirs twice as big? I don't get it.


I don’t get it either that the S lens is so long. But, it is optically outstanding and the same price (or it was) as a Nikon Z body with a 24-70 f4 when purchased as a kit.


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## GMCPhotographics (Oct 30, 2020)

privatebydesign said:


> Yes, and it is, and it is a shrinking niche which bodes poorly for more options. I do not believe the RF line will ever have the depth and range the EF line had.


I've always found if frustrating and slightly amusing that Canon just couldn't seem to be able to design and build a good / sharp 50mm. 85mm f1.2...double gauss optics...really sharp. 35mm f1.4 retrofocus double gauss...again...really sharp. 50mm f1.2...50mm f1.4 USM all soft wide open...all double Gauss designs. I use an original metal mount 50mm f1.8 from the first year of EOS manufacture which came bundled with my EOS 650. It's way sharper wide open than any of the 50mm f1.2 L's I've handled and the F1.4 USM's too. 
It'll be interesting if this new RF lens will be any sharper than the current EF version. IF it is...then Canon really could have built a better EF version if they wanted too. 
Looking at the lens placement, it looks like they ahve moved the optics forwards and the mechanicals back to where the mirrir box flange would normaly be. It's basically an EF lens with a space behind the rear optic. The old EF design sets the machanicals in front and round the set back optics to act as a sort of integral hood. So i'm guessing that this lens will have a much larger hood becuase the elements are very close to the front of the lens body.


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## ctk (Oct 30, 2020)

Maximilian said:


> Not only that.
> The basic double Gauss design stayed the same.
> But I see different gaps between the elements.
> And I see elements cut on both sides where one was only cut on one side (two working steps = more expensive).
> ...


ff
I'm going to go against my gut and look at this optimistically. The EF 50 1.8 STM's optical design was unchanged from the original 50 1.8 from the 80s, so the starting point for improvement is basically ground zero. Modern design + manufacturing and new coatings might go a really long way.


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## swkitt (Oct 30, 2020)

If I was Canon I would make it the same price as EF version, as the chinese will certainly be able to copy this quite easily and sell it for 50 bucks.


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## jvillain (Oct 30, 2020)

My guess is that we will see a decent increase in IQ from better tooling & CAD being available now as compared to when the plastic fantastic first rolled out.


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## jvillain (Oct 30, 2020)

gruhl28 said:


> Does anyone else find it odd that Canon makes "medium" quality and aperture lenses with IS in moderate wide angle (35mm RF, 24mm, 28mm, and 35 mm EF) and moderate telephoto focal lengths (85mm RF), but in the "standard" 50 mm they only make very high end and low end without IS? This was true in EF, and now it's the case with RF as well.
> 
> I'm actually surprised I haven't seen anyone complaining yet that this lens doesn't have IS. There is still no standard focal length prime lens from Canon with IS. Why?


With IBIS now becoming a thing in Canon land that will dampen some of the demand for IS in the lenses.


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## mangobutter (Oct 30, 2020)

SUNDOG04 said:


> I don’t get it either that the S lens is so long. But, it is optically outstanding and the same price (or it was) as a Nikon Z body with a 24-70 f4 when purchased as a kit.



Because the Nikon is using a modern, multi-element design with plenty of correction. It's better optically, but also expensive, heavy, large.

This new RF lens, to me, appears to be a simplistic double-gauss design. I'll take it a step further and say it even seems to be simply the EF 50 STM with lens groups shifted forward to make up for the flange distance with some (probable) slight projection tweaking and an additional element (maybe aspherical?) for improved sharpness wide open. Think about what the RF EF adapter is doing when you mount this lens, it's simply moving the elements forward. I think that's what this re-work is.

In other words, this new RF lens, to me, looks like a low-investment re-work of the 50 STM for mirrorless flange distance and RF mount, albeit with small changes to the lens formula to further enhance IQ (over the EF STM version)


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## BeenThere (Oct 30, 2020)

If you want cheap, don’t expect groundbreaking design or build. As always, you get (at best) what you pay for.


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## slclick (Oct 30, 2020)

Hasn't every iteration of the Nifty Fifty been a simplistic and low end engineering cost retooling? Oh and as for Prime niches, I live in the 40/135 niche group. I don't do 50mm, 40 just feels right to me. What's that? I should just take a few steps back?


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## lawny13 (Oct 30, 2020)

privatebydesign said:


> It is just the standard Double-Gauss design that has been around in innumerable formulae's since 1817.
> 
> 
> 
> ...



That isn't how lens design works. The centre of the lens elements for a lens of 50 mm FL needs to be about 50 mm away from the focal plane in a design that is as simple as possible. This is why it is the wider angles that tend to get smaller on mirrorless because the flange distance is smaller.

Additional glass is needed. when this FL to focal plane deviates.

Why do you think that the 70-200 nikon and sony lenses are about the same size as the DSLR ones? Why do you think the 50s are bigger than the nifty fifties from the DSLR cameras? Though the canon 70-200 is small when zoomed out it is about the same size as the rest zoomed in. 

What canon can gain from the flange distance though is the fact that the rear lens can be bigger, and thus it should allow for better sharpness across the frame. 

If this 50 is sharp wide open, and sharp in the corners it is already big gain over the EF50 stm. If it were quite as well.... that would be great.


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## dwarven (Oct 30, 2020)

I bet it will be $250. If it's sharper at f/1.8 than the EF version then it will be worth it. The one I have is quite smooshy wide open.


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## privatebydesign (Oct 30, 2020)

lawny13 said:


> That isn't how lens design works. The centre of the lens elements for a lens of 50 mm FL needs to be about 50 mm away from the focal plane in a design that is as simple as possible. This is why it is the wider angles that tend to get smaller on mirrorless because the flange distance is smaller.
> 
> Additional glass is needed. when this FL to focal plane deviates.
> 
> ...


Canon have made a cheap lens cheaply, which I am not criticizing them for by the way. They have taken a tried and true design and made modest optical formula changes despite the fact they had the opportunity to reinvent the wheel with a different mount.

The rear element is slightly larger in the new lens if the diagrams are to scale, and I would expect the RF 50 f1.8 to be an improvement over the EF version. But come on, designing a Doube-Gauss 50mm lens isn't rocket science even if you have the chance to throw in a moulded aspherical element, even the much maligned EF 50 f1.4 is sharper than the 100 L Macro at f5.6. That lens design has built in limitations as explained in the article I previously linked to, it is an interesting read.


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## lawny13 (Oct 30, 2020)

privatebydesign said:


> Canon have made a cheap lens cheaply, which I am not criticizing them for by the way. They have taken a tried and true design and made modest optical formula changes despite the fact they had the opportunity to reinvent the wheel with a different mount.
> 
> The rear element is slightly larger in the new lens if the diagrams are to scale, and I would expect the RF 50 f1.8 to be an improvement over the EF version. But come on, designing a Doube-Gauss 50mm lens isn't rocket science even if you have the chance to throw in a moulded aspherical element, even the much maligned EF 50 f1.4 is sharper than the 100 L Macro at f5.6. That lens design has built in limitations as explained in the article I previously linked to, it is an interesting read.



Look... personally I loved the ZA 55. I had hoped that canon would give me a good quality weather sealed and internally focusing 50. The ZA 55 was my walk around lens when I had the A7III, and I was wishing for a good one for RF. So... I am disappointed. My comment was mainly that it wasn't about moving the elements forward to have an adapter built in, but with this simple design the lens internals simply need to be moved forward. 

If canon doesn't give us a sharp, good 50. Then I will basically keep my EF stm adapted and just wait for a sigma or Tamron 50 prime to appear for the RF system down the road. I have bigger fish to fry, like the RF 100-500 and the RF 70-200.


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## jolyonralph (Oct 30, 2020)

I must admit I was hoping for something a bit more modern - something closer to the Sony/Zeiss 55mm FE lens which has 7 elements including a concave front element looks like this is going to be pretty close to the current 50mm EF lens in quality. But if it's cheap that's not a bad thing, but I think anything over $200 is going to be too much.


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## privatebydesign (Oct 31, 2020)

slclick said:


> Hasn't every iteration of the Nifty Fifty been a simplistic and low end engineering cost retooling? Oh and as for Prime niches, I live in the 40/135 niche group. I don't do 50mm, 40 just feels right to me. What's that? I should just take a few steps back?


No.

And no. I have zooms, I have primes, my most used lenses are manual focus TS-E primes, when I get an R5 it will be accompanied by the bargain 35 and 85 primes. But that doesn’t change the numbers, nor the economics when looked at from Canon’s perspective, as I said, I doubt we will ever have the breadth of lenses in the RF line we had in the EF line not least of which reasons is because it spanned such a developmental era of the camera industry.

The FL saw little comparative change, the FD went from the FL manual everything to auto aperture with a single failed stab at AF. The EF went from 135 format film through three different sized digital sensors and pioneered fully electronic communications, step less apertures, leading AF and IS, CAD, more development in exotic glass and molded aspheric lenses than you could shake a stick at and is current and world class even now three decades later.


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## stevelee (Oct 31, 2020)

slclick said:


> Hasn't every iteration of the Nifty Fifty been a simplistic and low end engineering cost retooling? Oh and as for Prime niches, I live in the 40/135 niche group. I don't do 50mm, 40 just feels right to me. What's that? I should just take a few steps back?


The idea is that a “normal” lens has a focal length equal to the diagonal of the sensor size. For “full frame” that is about 43mm. So it should be no surprise that 40mm seems more “normal“ to you than does 50mm. My first 35mm camera was a Yashica rangefinder camera with a 45mm lens. I took many of the best pictures I have ever taken with that camera. Because I was using the same focal length all the time, I didn’t have to put the camera up to my eye to focus the shot. It was almost like I had that frame in my brain and could look at the world that way. I eventually realized that a great benefit of doing photography for me was in how I see things, perceiving beauty or order in the ordinary.


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## stevelee (Oct 31, 2020)

I bought the EF 50mm f/1.4 to use on my T3i as a portrait lens more than anything else. It worked great for that purpose, and I didn’t experience anything that would justify complaints like I read here about that lens. If it is not terribly sharp in the corners, I would know about that, for example. I was using a crop sensor, so I wasn’t seeing the corners of FF. Also, in portraits, soft corners at most are a feature and not a bug. I don‘t recall the actual complaints, just that there is a lot of poopooing that lens.

Since I got the 6D2, I have not had occasion to use that lens. I don’t know what I’d need it for. My 85mm f/1.8 has taken over what I was using it for, and my kit zoom covers that focal length. It may be that I zoom to c. 50mm reasonably often, but I’m unaware of it. So I really can’t relate to the frequent laments here for 50mm lenses to suit various tastes.


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## slclick (Oct 31, 2020)

privatebydesign said:


> No.
> 
> And no. I have zooms, I have primes, my most used lenses are manual focus TS-E primes, when I get an R5 it will be accompanied by the bargain 35 and 85 primes. But that doesn’t change the numbers, nor the economics when looked at from Canon’s perspective, as I said, I doubt we will ever have the breadth of lenses in the RF line we had in the EF line not least of which reasons is because it spanned such a developmental era of the camera industry.
> 
> The FL saw little comparative change, the FD went from the FL manual everything to auto aperture with a single failed stab at AF. The EF went from 135 format film through three different sized digital sensors and pioneered fully electronic communications, step less apertures, leading AF and IS, CAD, more development in exotic glass and molded aspheric lenses than you could shake a stick at and is current and world class even now three decades later.



I see where you are coming from except for where you missed one of my words. Nifty.


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## canonnews (Oct 31, 2020)

lawny13 said:


> What canon can gain from the flange distance though is the fact that the rear lens can be bigger, and thus it should allow for better sharpness across the frame.
> 
> If this 50 is sharp wide open, and sharp in the corners it is already big gain over the EF50 stm. If it were quite as well.... that would be great.


yeah I admire your enthusiasm and positive outlook, but if canon wanted a sharp wide open lens, it wouldn't be a 6 element design. it also doesn't have the "RF classical" large rear element design either. it's basically 30-35mm backfocus distance lens dovetailed for the RF mount.


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## Tangent (Oct 31, 2020)

canonnews said:


> yeah I admire your enthusiasm and positive outlook, but if canon wanted a sharp wide open lens, it wouldn't be a 6 element design. it also doesn't have the "RF classical" large rear element design either. it's basically 30-35mm backfocus distance lens dovetailed for the RF mount.



Along that train of thought... I was scanning the 50 1.8 EF STM reviews on B&H and found four leading quality complaints in the 1 and 2 star reviews to be: noisy AF, manual focus ring dodgy in use, lens hard to mount on camera, and, as mentioned, lens soft. It will be interesting to see if Canon addressed these other three quality "opportunities" as well.


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## lawny13 (Oct 31, 2020)

jolyonralph said:


> I must admit I was hoping for something a bit more modern - something closer to the Sony/Zeiss 55mm FE lens which has 7 elements including a concave front element looks like this is going to be pretty close to the current 50mm EF lens in quality. But if it's cheap that's not a bad thing, but I think anything over $200 is going to be too much.



I do am fine with that, but then my opinion is that canon should also have a mid range option sometime. 200 vs 2700 dollar options is a massive gap. Same goes for size. Think they would be able to sell a good F1.4 well. In particular to R6 and R5consumers


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## mb66energy (Oct 31, 2020)

canonnews said:


> yeah I admire your enthusiasm and positive outlook, but if canon wanted a sharp wide open lens, it wouldn't be a 6 element design. it also doesn't have the "RF classical" large rear element design either. it's basically 30-35mm backfocus distance lens dovetailed for the RF mount.


I am another person who thinks that this lens will be a very good lens in absolute terms:
The upcoming RF 50 has only 6 elements and 5 groups so contrast will be really good (if they use high quality coatings) but correction will be at a slightly lower level compared to e.g. an RF 50 1.2. Why slightly? An aspherical element is essential to make a reasonably good f/1.2 lens (EF 50 f/1.2) but it will enable a very good f/1.8 max aperture!
Spherical aberration (due to the typical spherical lens surfaces) is the strongest enemy for high aperture lenses at high apertures and he best antidote is ... an aspherical lens.


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## JTPhotography (Oct 31, 2020)

$229


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## Antono Refa (Oct 31, 2020)

lawny13 said:


> That isn't how lens design works. The centre of the lens elements for a lens of 50 mm FL needs to be about 50 mm away from the focal plane in a design that is as simple as possible. This is why it is the wider angles that tend to get smaller on mirrorless because the flange distance is smaller.



I'm far from being an expert, but shouldn't it be the aperture, rather than the center of the lens elements?



lawny13 said:


> Additional glass is needed. when this FL to focal plane deviates.
> 
> <snip>
> 
> What canon can gain from the flange distance though is the fact that the rear lens can be bigger, and thus it should allow for better sharpness across the frame.



My impression was the additional glass would not be needed for the FL range between RF's 20mm and EF's 44mm.


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## WoodyWindy (Oct 31, 2020)

Interesting discussion. As with a few others, I immediately honed in on the facts that 
1. the whole set of elements was shifted "outward" to stay very close to the same focal plane distance. 
2. the "inner" groupings are inverted compared to the classic design.
3. the actual silhouettes clearly show differences.

I don't have the optics expertise to know exactly how these changes affect the resultant image, but Canon is not known for making changes for their own sakes. We have to assume we're going to see some pretty significant improvement over the classic 50 f1.8 offerings.


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## jolyonralph (Oct 31, 2020)

WoodyWindy said:


> Interesting discussion. As with a few others, I immediately honed in on the facts that
> 1. the whole set of elements was shifted "outward" to stay very close to the same focal plane distance.
> 2. the "inner" groupings are inverted compared to the classic design.
> 3. the actual silhouettes clearly show differences.
> ...



There are two reasons to change a design that's worked well in the past - one is to improve quality and the other is to reduce production cost. Or, very occasionally, both.


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## Sporgon (Oct 31, 2020)

jolyonralph said:


> There are two reasons to change a design that's worked well in the past - one is to improve quality and the other is to reduce production cost. Or, very occasionally, both.


Do designs that have worked well in the past still meet the demands and expectations required to be considered as working well to day ?


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## privatebydesign (Oct 31, 2020)

Sporgon said:


> Do designs that have worked well in the past still meet the demands and expectations required to be considered as working well to day ?


For photographers, almost without exception, YES. For forum nerds, self appointed YouTube experts, ‘reviewers’, and people that just love to argue, no.


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## Sporgon (Oct 31, 2020)

privatebydesign said:


> For photographers, almost without exception, YES. For forum nerds, self appointed YouTube experts, ‘reviewers’, and people that just love to argue, no.


 So true !


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## deleteme (Oct 31, 2020)

The fact that the elements are offset to the front illustrates the thinness of the argument that mirrorless bodies will always give us smaller, lighter lenses. Some designs may benefit but even the WA lenses are not seeing the dramatic reduction in mass that was promised.


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## SteveC (Nov 1, 2020)

Sporgon said:


> Do designs that have worked well in the past still meet the demands and expectations required to be considered as working well to day ?





privatebydesign said:


> For photographers, almost without exception, YES. For forum nerds, self appointed YouTube experts, ‘reviewers’, and people that just love to argue, no.



But what about lens design rot? I'm sure I've seen designs rot with age.

(And yes, I guess that makes me a "people that just love to argue" even if only in jest.)


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## Eowhiskass (Nov 1, 2020)

I hope it would be compatible with es-68 lens hood


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## WoodyWindy (Nov 1, 2020)

jolyonralph said:


> There are two reasons to change a design that's worked well in the past - one is to improve quality and the other is to reduce production cost. Or, very occasionally, both.


The classic 50 f1.8 optical formula is as old as the hills, and has been applied to/reused in multiple generations and iterations of this lowest-cost prime lens in the EF series, including the post-digital age. You could say, it is "well proven", and is probably VERY cost effective to produce.  Therefore, the low-cost option for a native RF mount version would have stopped at shifting the optics out, and fixing up the mount.

Canon didn't do that. Instead, here there is clear evidence of substantial work on the optical formula. That bodes well for improvement in the output, including both the image quality (aberrations, vignetting) at the edges, probably overall color/contrast, and I would guess minimum focus distance as well. (how many folks have inverted a 50 f1.8 to create an "instant" macro lens?)

In the end, I'm excited to see what this baby can do.


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## Sporgon (Nov 1, 2020)

WoodyWindy said:


> The classic 50 f1.8 optical formula is as old as the hills, and has been applied to/reused in multiple generations and iterations of this lowest-cost prime lens in the EF series, including the post-digital age. You could say, it is "well proven", and is probably VERY cost effective to produce.  Therefore, the low-cost option for a native RF mount version would have stopped at shifting the optics out, and fixing up the mount.
> 
> Canon didn't do that. Instead, here there is clear evidence of substantial work on the optical formula. That bodes well for improvement in the output, including both the image quality (aberrations, vignetting) at the edges, probably overall color/contrast, and I would guess minimum focus distance as well. (how many folks have inverted a 50 f1.8 to create an "instant" macro lens?)
> 
> In the end, I'm excited to see what this baby can do.



Well maybe. I think you might be giving Canon more praise for working a new optical variation of the classic double gauss than they deserve.

If the block diagram at the beginning of this thread is correct it looks like Canon have reused their lens design from the 1964 Canonet rangefinder camera ( " the poor man's Leica") that has a 45mm f/1.7 lens, and replaced one element with the aspherical one. If you go to the wiki page for Double Gauss lens that PBD linked to at the beginning of this thread you can see the Canonet block diagram at the bottom of the first diagram page.




Canon have given the first doublet a curved matting which is much more expensive to do than the straight bond in the 1964 lens, and this should give a more pleasant rendering. However my guess would still be that the lens is going to be sharper at the expense of rendering / bokeh. In other words it will chart well.


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## WoodyWindy (Nov 1, 2020)

Sporgon said:


> Well maybe. I think you might be giving Canon more praise for working a new optical variation of the classic double gauss than they deserve.
> 
> If the block diagram at the beginning of this thread is correct it looks like Canon have reused their lens design from the 1964 Canonet rangefinder camera ( " the poor man's Leica") that has a 45mm f/1.7 lens, and replaced one element with the aspherical one. If you go to the wiki page for Double Gauss lens that PBD linked to at the beginning of this thread you can see the Canonet block diagram at the bottom of the first diagram page.
> 
> ...


Reposting the original for easy reference. (I actually had one of those old Canonet cameras, by the way). The differences are still pretty significant. I'm sure it will chart, the question is, will this dog hunt? We'll see in a few weeks.


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## gruhl28 (Nov 1, 2020)

jvillain said:


> With IBIS now becoming a thing in Canon land that will dampen some of the demand for IS in the lenses.


True, but they put IS in the 35mm and 85mm. Granted, those were released before a body with IBIS, but this just leads to the question of why they decided to release low to mid-price 35mm and 85mm lenses before the 50mm.


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## maves (Nov 2, 2020)

I'm cautiously optimistic about what this lens will be. I really hope that it's a star, Leica have shown that you can make a simple 50mm double gauss design absolutely stellar. Not that I'm expecting a summicron, but the fact that it's a double gauss design doesn't put me off in the slightest.


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## lawny13 (Nov 2, 2020)

Antono Refa said:


> I'm far from being an expert, but shouldn't it be the aperture, rather than the center of the lens elements?
> 
> 
> 
> My impression was the additional glass would not be needed for the FL range between RF's 20mm and EF's 44mm.



FL is from the optical center of the lens to the optical center.

They cover it quite well here: https://photographylife.com/what-is-focal-length-in-photography#definition-of-focal-length

And just as they imply in there, things can get complicated real fast once you dive into the physics of it all. Simply based on this explanation you can see why lenses end up being what they are. The flange distance directly contributes to the distance of the optical center vs the sensor/film plane. 

My point about additional glass had to do with WA lenses. A 14 mm lens is already by definition further in mm regarding its optical center compared to the optical plane. And thus additional glass is required to shift that projection. That is why WA lenses tended to be huge on DSLRs. With smaller flange distances less glass is needed to shift this focal point. 

50s and 40s typically were relatively small on DLSRs due to the flange distance and lens FL. But for MILC with the flange being further back you end up with a longer lens. So when people talk as if the 50 mm lenses aren't taking advantage of the shorter flange distance they simply don't know what they are talking about.


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## jolyonralph (Nov 2, 2020)

gruhl28 said:


> True, but they put IS in the 35mm and 85mm. Granted, those were released before a body with IBIS, but this just leads to the question of why they decided to release low to mid-price 35mm and 85mm lenses before the 50mm.



Probably because a significant percentage of upgraders already have an EF 50mm of one kind or another (I have four: 50mm f/1.8II, 50mm f/2.5 macro, Yongnuo 50mm 1.4 and the EF 50mm f/1.2L), and even with the EF-RF adaptor it's still a lightweight small combination.

Moving this to RF makes sense now if it's cheap enough most RF mount users will upgrade.


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## Del Paso (Nov 3, 2020)

Sporgon said:


> Do designs that have worked well in the past still meet the demands and expectations required to be considered as working well to day ?


I'm using on a regular basis a 1969 Leica M 50mm f2 Summicron.
Sharpness and contrast (edge to edge !!!) are still outstanding, even on EOS R cameras, and , for closeups, on high MP EOS DSLRs.
So: a BIG, AN ENORMOUS YES


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## SwissFrank (Sep 23, 2022)

WoodyWindy said:


> (how many folks have inverted a 50 f1.8 to create an "instant" macro lens?)


My old Rollei SL66 (kind of a Hasselblad but with bellows) could mount the 80/2 backwards for macro.


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