# Patent: Lots of fast RF prime lens optical formulas



## Canon Rumors Guy (Aug 27, 2020)

> Keith over at Northlight Images has uncovered a patent at the USPTO that shows Canon working on a lot of fast RF prime lenses.
> The optical formulas in this patent include:
> 
> Canon RF 50mm f/1.8
> ...



Continue reading...


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## fox40phil (Aug 27, 2020)

Still hoping for: 
A 135 f/1.8 (like the Sigma & Sonys!)
A lightweight 120-300 f/2.8 (+ 2x of this zoomrange) etc...
And some new DO lenses! (A newer 400 4.0 II...with less then 3,3m focus distance!)


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## marathonman (Aug 27, 2020)

******* unless that 300mm is f/1.4 and only weighs 64g. It also needs to be smaller than the 40mm pancake. I've seen a few YouTube videos about The Bridge over the River Kwai, so I know a thing or too about engineering. If Canon don't do this, then it's clear they are simply trying to protect the feelings sales of their bigger white lenses....


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## BeenThere (Aug 27, 2020)

Canon Rumors Guy said:


> Continue reading...


The 80 and 85mm f~1.4 don’t make much sense after the near perfect RF 85mm f~1.2


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## keithcooper (Aug 27, 2020)

Reminder before the complaints roll in...
The examples in the patent just cover potential designs that fit a certain design principle - they are just optical desigs, not full lens designs.

There are lenses I want too, but they don't fit the examples n the patent application ;-)


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## BeenThere (Aug 27, 2020)

marathonman said:


> ******* unless that 300mm is f/1.4 and only weighs 64g. It also needs to be smaller than the 40mm pancake. I've seen a few YouTube videos about The Bridge over the River Kwai, so I know a thing or too about engineering. If Canon don't do this, then it's clear they are simply trying to protect the feelings sales of their bigger white lenses....


With their new blue diamond material front element, I think they can accommodate you.


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## SteveC (Aug 27, 2020)

marathonman said:


> ******* unless that 300mm is f/1.4 and only weighs 64g. It also needs to be smaller than the 40mm pancake. I've seen a few YouTube videos about The Bridge over the River Kwai, so I know a thing or too about engineering. If Canon don't do this, then it's clear they are simply trying to protect the feelings sales of their bigger white lenses....



We know they're holding back on the 1-1000mm f/1.0 superzoom that fits in the unused card slot when not in use, you know, to protect their other lenses.


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## marathonman (Aug 27, 2020)

BeenThere said:


> With their new blue diamond material front element, I think they can accommodate you.


The blue diamond material is actually thermal paste designed to passively cool the R5 and allow 3 weeks continuous recording in 8K.


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## SteveC (Aug 27, 2020)

BeenThere said:


> The 80 and 85mm f~1.4 don’t make much sense after the near perfect RF 85mm f~1.2



That depends...perhaps they're aimed at a much lower tier similar to the EF non L lenses.


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## BeenThere (Aug 27, 2020)

SteveC said:


> That depends...perhaps they're aimed at a much lower tier similar to the EF non L lenses.


Perhaps, but we don’t usually see that aperture on non L lenses.


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## Ruiloba (Aug 27, 2020)

Canon RF 300mm f/2.8 , could this be the first of the big one whites for wildlife? Want to see the 400mm F2.8 and 500mm F4


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## SecureGSM (Aug 27, 2020)

BeenThere said:


> The 80 and 85mm f~1.4 don’t make much sense after the near perfect RF 85mm f~1.2


One may argue that a $1800 85/1.4 L lens could sell a tad better than a much larger and heavier $3000 85/1.2?


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## Besisika (Aug 27, 2020)

Can't wait for the 135mm F2. Hope to shoot outdoor portraits wide open on that one.


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## Deleted member 381342 (Aug 27, 2020)

Ruiloba said:


> Canon RF 300mm f/2.8 , could this be the first of the big one whites for wildlife? Want to see the 400mm F2.8 and 500mm F4



I am expecting the RF 300 and 500 at the same time. 300 is lovely for some wildlife but I always need to crop in with mine.


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## H. Jones (Aug 27, 2020)

SecureGSM said:


> One may argue that a $1800 85/1.4 L lens could sell a tad better than a much larger and heavier $3000 85/1.2?



I'd preorder a 85mm f/1.4 on day one if it was smaller and cheaper than the 85 1.2. I love the EF 85 F/1.4, and was so close to buying one when the RF mount was announced and decided against it to start moving towards RF lenses.

I am half tempted to get the 85 1.2, but I think I would get more use out of a 1.4. A lot of my portraits with flash are stopped down anyway, but I'd still like something a little faster than the F/2 for lowlight. Portraits aren't my main source of income and I often use a 70-200 or 24-70, so it'd hard to justify the 1.2.


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## Antono Refa (Aug 27, 2020)

BeenThere said:


> The 80 and 85mm f~1.4 don’t make much sense after the near perfect RF 85mm f~1.2



I think there's room for an RF 85mm f/1.8 IS, which would benefit from being smaller, lighter, and cheaper.


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## jolyonralph (Aug 27, 2020)

Antono Refa said:


> I think there's room for an RF 85mm f/1.8 IS, which would benefit from being smaller, lighter, and cheaper.



Not with the RF 85mm f/2 IS out.


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## jolyonralph (Aug 27, 2020)

In terms of which of these might actually become products in the near(ish) future I'll say:


Canon RF 50mm f/1.8 - Obviously yes
Canon RF 80mm f/1.4 - Nope
Canon RF 85mm f/1.4 - Nope
Canon RF 85mm f/1.8 - More Nope 
Canon RF 100mm f/2 - I'm going to say no
Canon RF 135mm f/2 - Maybe
Canon RF 300mm f/2.8 - Yes

I know some people want a 135mm f/1.8 or 1.4 but the EF 135 2.0 has always been a spectacular lens, and part of this is due to the relatively small size and low weight. Not sure I'd want a more expensive and heavier version.


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## SteveC (Aug 27, 2020)

BeenThere said:


> Perhaps, but we don’t usually see that aperture on non L lenses.



My first thought was, wait a minute, I have one of those, it can't be uncommon.

Then I realized I was thinking of my *50* mm f/1.4, which of course is distinctly NOT an 85mm. And it's certainly not like my 85mm *f/1.8*; similar logic. (See "A is A" for further explanation.  ) Yes, an 85mm f/1.4 is probably too close to the f/1.2 to make much sense...unless it really is some sort of new mid-range option (oh, say about $1000-1200); even then, it might not be distinct enough.

So yeah, never mind what I said.


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## MaxDiesel (Aug 27, 2020)

BeenThere said:


> The 80 and 85mm f~1.4 don’t make much sense after the near perfect RF 85mm f~1.2



Cost and Size... a lineup always need 1.4 and 1.8 lenses. 
Canon EF as 85mm 1.2, 1.4, and 1.8 So it makes perfect sense.


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## MaxDiesel (Aug 27, 2020)

jolyonralph said:


> In terms of which of these might actually become products in the near(ish) future I'll say:
> 
> 
> Canon RF 50mm f/1.8 - Obviously yes
> ...



How can you say Nope to an 85mm 1.4 or 1.8 (for canon the 1.2 will never be a hot of the shelves lens) they need smaller lighter version that cost half the price. You might not need it but the lineup does.


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## Daner (Aug 27, 2020)

jolyonralph said:


> I know some people want a 135mm f/1.8 or 1.4 but the EF 135 2.0 has always been a spectacular lens, and part of this is due to the relatively small size and low weight. Not sure I'd want a more expensive and heavier version.



I'd be very happy if they released an RF 135 f/2L IS. Nano-USM and weather sealing are more important to me than 0.5x macro, but I certainly wouldn't mind it if they could include all three, as long as the IQ meets or exceeds that of the EF version, and the price and weight don't get completely out of hand.


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## Pixel (Aug 27, 2020)

Ruiloba said:


> Canon RF 300mm f/2.8 , could this be the first of the big one whites for wildlife? Want to see the 400mm F2.8 and 500mm F4


Since they never updated the EF to vIII, I would say this is guaranteed next year before the Olympics and released with the EOS 1R. The longer great whites, I think we might be waiting a bit since the EF vIII's are still pretty new and work perfectly with the RF adaptor.


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## filmmakerken (Aug 27, 2020)

Is it possible that any of these Cine Primes?


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## keithcooper (Aug 27, 2020)

filmmakerken said:


> Is it possible that any of these Cine Primes?


Unlikely -see the specs in the patent. They are all full frame.
However I did note that several have quite a large back focus. RF lenses don't have to have a short distance.


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## Danglin52 (Aug 27, 2020)

Ruiloba said:


> Canon RF 300mm f/2.8 , could this be the first of the big one whites for wildlife? Want to see the 400mm F2.8 and 500mm F4


I want my RF 200-500 f4-f5.6 + integrated 1.4x TC @f6.3 & under 6lbs or less!!!!! I agree that this may be the first BW. I actually expected both the 300 & 500 since they did not get EF Mark III updates and weight reduction.


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## jeffa4444 (Aug 27, 2020)

BeenThere said:


> The 80 and 85mm f~1.4 don’t make much sense after the near perfect RF 85mm f~1.2


I disagree. Ive the EF 85mm f1.4L IS USM which I use often. I bought it because unlike the 1.2 it has IS and whilst the bokeh is different it’s still very creamy when I use it for portraits.


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## richperson (Aug 28, 2020)

If the 135mm f/2 is the fastest at this focal length I will be disappointed. Really want at least a 135mm f/1.8 or 70-135mm f/2.


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## vangelismm (Aug 28, 2020)

jolyonralph said:


> In terms of which of these might actually become products in the near(ish) future I'll say:
> 
> 
> Canon RF 50mm f/1.8 - Obviously yes
> ...



Canon is the maker of 03 85mm between 1.2 and 1.8...


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## Mr Majestyk (Aug 28, 2020)

Good to see the 300 f/2.8 patent, but where the hell is the 500 f/4. Hopefully Canmon will switch to linear drive motors too for the superteles and consider a 600 f/5.6L DO IS or 800 f/8L DO IS.

Other than that the 85 f/1.8 and 135 f/2 are welcome.


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## Jethro (Aug 28, 2020)

Could the 100mm f/2 be a macro?


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## RobbieHat (Aug 28, 2020)

Where are the UWA fast primes or fast zoom? Canon has ceded this market to Sigma and there are a lot of us that would shell out money for a native option. They have also been behind both Nikon and Sony in this space. Come on Canon, show us astrophotographers some love and what the RF Mount can do!


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## jonthegreat (Aug 28, 2020)

all these are minor variations of what we already have. i need a wide prime and a solid macro. please canon.


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## masterpix (Aug 28, 2020)

BeenThere said:


> The 80 and 85mm f~1.4 don’t make much sense after the near perfect RF 85mm f~1.2


If the price is half of the 1.2 than it will be, not all people can afford $2000+ lenses, and if Canon wants to increase their market, lenses is where the big deal is. For once you buy a body, you will probably use it until it dies out, those cameras, even 10 year old gives wonderful images. but you will always like to expand your choice in lenses.The same goes to the 600 and 800 F11 lenses, those are a good compromise between cash and focal length, many people who like to shoot animals will buy them cause now they can afford them instead of $3000+ white lenses.


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## Twinix (Aug 28, 2020)

keithcooper said:


> Unlikely -see the specs in the patent. They are all full frame.


C500 II


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## Daner (Aug 28, 2020)

Danglin52 said:


> I want my RF 200-500 f4-f5.6 + integrated 1.4x TC @f6.3 & under 6lbs or less!!!!! I agree that this may be the first BW. I actually expected both the 300 & 500 since they did not get EF Mark III updates and weight reduction.



I have enjoyed borrowing the EF 200-400 f/4L + 1.4x, but I have a hard time believing that it will be physically possible for them to add an additional 100mm of reach while simultaneously reducing the weight from 7.9 lbs to under 6 lbs. Much more realistic to consider the development from the EF 100-400L II to the RF 100-500L, which dropped a half a pound while adding a few mm in overall length.


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## blackcoffee17 (Aug 28, 2020)

Jethro said:


> Could the 100mm f/2 be a macro?



I would be pretty sad if they made 100 F2 Macro. I don't want to lug around an 1kg lens for macro. Or make an F4 version also who only needs it for macro and using no aperture wider than F8


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## TominNJ (Aug 28, 2020)

The EF 14mm 2.8 II dates to 2007 and is seemingly due for an upgrade.


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## esglord (Aug 28, 2020)

masterpix said:


> If the price is half of the 1.2 than it will be, not all people can afford $2000+ lenses, and if Canon wants to increase their market, lenses is where the big deal is. For once you buy a body, you will probably use it until it dies out, those cameras, even 10 year old gives wonderful images. but you will always like to expand your choice in lenses.The same goes to the 600 and 800 F11 lenses, those are a good compromise between cash and focal length, many people who like to shoot aimals will buy them cause now they can afford them instead of $3000+ white lenses.


Spot on for me at least. I will buy either the 600mm or 800mm before I upgrade my camera (even though I'm jealous of AF II). Also, if canon comes out with any one of a native RF f/1.4L prime in 35mm, 50mm, or 85mm for ~$1600, I will buy it immediately. I expect to wait a while though given the nice alternatives already available to be adapted from EF.


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## Random Orbits (Aug 28, 2020)

TominNJ said:


> The EF 14mm 2.8 II dates to 2007 and is seemingly due for an upgrade.



With the RF 15-35mm going down to 15mm at f/2.8, I don't see much of a reason for a 14mm f/2.8 prime, which is also very expensive. If Canon decides to produce a 14mm prime, I'm guessing it'd havea larger max aperture (f/2?) to better differentiate it from the zooms (RF 15-35, EF 11-24).


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## filmmakerken (Aug 28, 2020)

keithcooper said:


> Unlikely -see the specs in the patent. They are all full frame.
> However I did note that several have quite a large back focus. RF lenses don't have to have a short distance.


The full frame nature doesn't negate the possibility of Cinema lenses. The R5 shoots full frame video, Sigma makes a FF set of Cine lenses, and all Zeiss cinema lenses are full frame.
You're likely correct that these aren't Cine lenses but, with the announcement that Canon is releasing a RF-mount video camera, it seems Cine lenses should be coming.


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## Danglin52 (Aug 28, 2020)

Daner said:


> I have enjoyed borrowing the EF 200-400 f/4L + 1.4x, but I have a hard time believing that it will be physically possible for them to add an additional 100mm of reach while simultaneously reducing the weight from 7.9 lbs to under 6 lbs. Much more realistic to consider the development from the EF 100-400L II to the RF 100-500L, which dropped a half a pound while adding a few mm in overall length.


I think the comparison should be more with the 400 III & 600 III since the 200-400 is a large lens and some of the weight loss can come from using different materials on the barrel and other components. I would hope around 7lbs which would still be a big win. My first big white was the original 600mm @ almost 14lbs and I never would have imagined the 3rd generation would land at 6.7 lbs. You have to dream


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## RobbieHat (Aug 28, 2020)

TominNJ said:


> The EF 14mm 2.8 II dates to 2007 and is seemingly due for an upgrade.



and an improvement in f stop. Maybe a f1.8 (ala Sigma EF version) or even better an f 1.4. 

bob


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## TominNJ (Aug 28, 2020)

RobbieHat said:


> and an improvement in f stop. Maybe a f1.8 (ala Sigma EF version) or even better an f 1.4.
> 
> bob



correct for coma and I’d go all in on that. Canon made the Ra body. They should make a lens for it too.


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## Jasonmc89 (Aug 28, 2020)

I’ll have that 300mm 2.8 please!


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## privatebydesign (Aug 28, 2020)

I’m a little surprised I haven’t seen any rumors for a 35 L yet, it is such a staple focal length for so many photographer.


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## Olivier11986 (Aug 29, 2020)

Ruiloba said:


> Canon RF 300mm f/2.8 , could this be the first of the big one whites for wildlife? Want to see the 400mm F2.8 and 500mm F4


I don't want to see the price though


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## Olivier11986 (Aug 29, 2020)

Codebunny said:


> I am expecting the RF 300 and 500 at the same time. 300 is lovely for some wildlife but I always need to crop in with mine.


I like the handholdability of the 300 2.8 and with a 2X TC you get a very good 600!


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## Deleted member 381342 (Aug 29, 2020)

Olivier11986 said:


> I like the handholdability of the 300 2.8 and with a 2X TC you get a very good 600!



Mine isn't hand holdable much, but mine is the non IS 1988 edition. It lives on a monopod for me.


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## Franklyok (Aug 29, 2020)

Finally 135 mm update.

85 madness, sounds like canon can't get over it.


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## Franklyok (Aug 29, 2020)

Franklyok said:


> Finally 135 mm update.
> 
> 85 madness, sounds like canon can't get over it.



Is the 135 mm big enough, to give 8 stops ibis?


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## scyrene (Aug 29, 2020)

RobbieHat said:


> and an improvement in f stop. Maybe a f1.8 (ala Sigma EF version) or even better an f 1.4.



Two stops wider? You don't want much!


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## jolyonralph (Aug 30, 2020)

vangelismm said:


> Canon is the maker of 03 85mm between 1.2 and 1.8...



And there are already 3 85mm lenses for the RF mount. A fourth? No.


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## jolyonralph (Aug 30, 2020)

MaxDiesel said:


> How can you say Nope to an 85mm 1.4 or 1.8 (for canon the 1.2 will never be a hot of the shelves lens) they need smaller lighter version that cost half the price. You might not need it but the lineup does.



Because they already have two 85mm 1.2 lenses, and an 85mm f2 lens for those without deep pockets. There is room for a 1.4L IS eventually, but I don't think that time is now.


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## MaxDiesel (Aug 30, 2020)

jolyonralph said:


> Because they already have two 85mm 1.2 lenses, and an 85mm f2 lens for those without deep pockets. There is room for a 1.4L IS eventually, but I don't think that time is now.


Of course there is... the F1.2 and F1.2DS are beasts and not for everyone... the f/2 isn’t enough for most. We need a 1.4 or 1.8 with IS... and the time is NOW. You wont make people switch from Sony/Nikon without these staple lenses. I was surprised they jumped onto the F1.2 primes and F/2 zooms first.


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## DennisHuiberts (Aug 30, 2020)

What I don't see to grasp (and I hope somebody does know the answer) is the proclaimed benefit of the new mirrorless mounts (both Canon and Nikon). We've been told that the new mounts can results in new/better optical formulas. We haven't seen any "extremes" however. Yes, ofcourse we now have the 600mm and 800mm F11 which weren't possible with DSLR autofocus sytems, but besides that, most that is offered in RF mount is also available in EF. Does somebody know and could please explain what the real world benefits of these new mounts are?


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## DennisHuiberts (Aug 30, 2020)

Jasonmc89 said:


> I’ll have that 300mm 2.8 please!



May I ask what your reasoning is in getting this one instead of the EF mount one? Thanks.


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## Jasonmc89 (Aug 31, 2020)

DennisHuiberts said:


> May I ask what your reasoning is in getting this one instead of the EF mount one? Thanks.


Because I want an R5 and I shoot wildlife. Why wouldn’t I?


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## ldbee (Aug 31, 2020)

Really want the 50mm announcement, my current EF 50 I’ve had for 9 years, and it appears to be on the fritz


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## tron (Sep 1, 2020)

Daner said:


> I have enjoyed borrowing the EF 200-400 f/4L + 1.4x, but I have a hard time believing that it will be physically possible for them to add an additional 100mm of reach while simultaneously reducing the weight from 7.9 lbs to under 6 lbs. Much more realistic to consider the development from the EF 100-400L II to the RF 100-500L, which dropped a half a pound while adding a few mm in overall length.


...


RobbieHat said:


> and an improvement in f stop. Maybe a f1.8 (ala Sigma EF version) or even better an f 1.4.
> 
> bob


 although I would be delighted to see that allow me a slight correction : that is a completely new lens not an improvement...


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## tron (Sep 1, 2020)

Also I do have Sigma 14 1.8 and it works just fine with EF-RF adapter on my EOS R so say a 3K Canon 14 1.8 would have a competition.


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## Rivermist (Sep 1, 2020)

Franklyok said:


> Finally 135 mm update.
> 
> 85 madness, sounds like canon can't get over it.


Agreed, while 85mm is a key focal length I find 135mm to be the ideal portrait and mid-telephoto lens, making more sense as a prime since 85mm is included in most mid-zooms (close to the 70mm of a 24-70, inside the 24-105 bracket), whereas if I want to have the mid-zoom + 2 large(r) aperture primes then a 24, 28 or 35mm prime + a 135mm prime provides an expansion of the available focal lengths associated with the 24-70 or 24-105. 
Hopefully these primes will have IS so that I don't have to buy the R6 (yet) to get IS. 
An aperture of f:2.0 is good enough, I would not want the lens to be a monster, otherwise one might as well get the RF 70-200L IS 2.8. 
I owned and loved the EF 135 f:2, and also many years ago the FD 135mm f:2.5. Both allowed for great intimate pictures of people and creative street photography.


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## RobbieHat (Sep 1, 2020)

tron said:


> ...
> although I would be delighted to see that allow me a slight correction : that is a completely new lens not an improvement...



New lens for Canon. Something Sigmas has had out for a few years now.


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## Rivermist (Sep 1, 2020)

DennisHuiberts said:


> What I don't see to grasp (and I hope somebody does know the answer) is the proclaimed benefit of the new mirrorless mounts (both Canon and Nikon). We've been told that the new mounts can results in new/better optical formulas. We haven't seen any "extremes" however. Yes, ofcourse we now have the 600mm and 800mm F11 which weren't possible with DSLR autofocus sytems, but besides that, most that is offered in RF mount is also available in EF. Does somebody know and could please explain what the real world benefits of these new mounts are?


Well there are some interesting lenses such as the 28-70 f:2.0 (which can use the IBIS of R5 / R6), the 15-35 L f:2.8 which gets IS (with the EF mount only the f:4.0 has IS), ditto the 24-70 f:2.8 IS. The 70-200 f:2.8 IS is extraordinarily compact, not sure of course whether Canon could have produced the same lens in EF but chose to have all it's L lenses in 70-200 be internal focusing only. The 35mm f:1.8 is interesting because the large glass is camera-side and the front lens is small, contrary to the EF 35mm f:2.0 (not quite sure what to make of that, but interesting). I am personally waiting for the 70-135mm L f:2.0, as far as I know nothing similar in EF. To your point I think that the benefits of RF in terms of optical design decrease as one goes to longer telephoto lenses, with only the electronics of RF (4 additional pins, faster data transfers, interaction of IBIS and lens IS) and a slightly wider diameter allowing for some innovation. The biggest difference s of course the distance to sensor, without a mirror the glass can extend closer to the sensor. It is surprising that more wide angle lenses have not come out yet because that is where I would expect the RF to deliver a bigger impact, e.g. for the successor to the 11-24mm, or a 14mm / 17mm / 20mm prime (the latter two were present in the FD lineup but never had an EF equivalent).
_If the “back focus” distance between a lens’ rear element and the camera’s sensor is too far, the light entering the rear element is condensed and is harder to do aberration correction on. Lenses counteract this by making the front element (and whole lens) larger and bulkier. But by moving the rear element closer to the sensor (i.e. a short back focus), Canon spreads out the light rays passing through the rear element, making it easier to reduce aberration. _(https://petapixel.com/2019/06/17/canon-this-is-why-rf-lenses-are-outstanding/). Does this answer your question (full disclosure I am just a camera enthusiast, not an optical engineer).


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## Franklyok (Sep 3, 2020)

And none was 1.0 like fuji 50mm 1.0


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## Franklyok (Sep 3, 2020)

Rivermist said:


> Well there are some interesting lenses such as the 28-70 f:2.0 (which can use the IBIS of R5 / R6), the 15-35 L f:2.8 which gets IS (with the EF mount only the f:4.0 has IS), ditto the 24-70 f:2.8 IS. The 70-200 f:2.8 IS is extraordinarily compact, not sure of course whether Canon could have produced the same lens in EF but chose to have all it's L lenses in 70-200 be internal focusing only. The 35mm f:1.8 is interesting because the large glass is camera-side and the front lens is small, contrary to the EF 35mm f:2.0 (not quite sure what to make of that, but interesting). I am personally waiting for the 70-135mm L f:2.0, as far as I know nothing similar in EF. To your point I think that the benefits of RF in terms of optical design decrease as one goes to longer telephoto lenses, with only the electronics of RF (4 additional pins, faster data transfers, interaction of IBIS and lens IS) and a slightly wider diameter allowing for some innovation. The biggest difference s of course the distance to sensor, without a mirror the glass can extend closer to the sensor. It is surprising that more wide angle lenses have not come out yet because that is where I would expect the RF to deliver a bigger impact, e.g. for the successor to the 11-24mm, or a 14mm / 17mm / 20mm prime (the latter two were present in the FD lineup but never had an EF equivalent).
> _If the “back focus” distance between a lens’ rear element and the camera’s sensor is too far, the light entering the rear element is condensed and is harder to do aberration correction on. Lenses counteract this by making the front element (and whole lens) larger and bulkier. But by moving the rear element closer to the sensor (i.e. a short back focus), Canon spreads out the light rays passing through the rear element, making it easier to reduce aberration. _(https://petapixel.com/2019/06/17/canon-this-is-why-rf-lenses-are-outstanding/). Does this answer your question (full disclosure I am just a camera enthusiast, not an optical engineer).



As long as there is no patent to 70-135, there is no hope.


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## Rivermist (Sep 3, 2020)

Franklyok said:


> As long as there is no patent to 70-135, there is no hope.


This 70-135 f:2.0 lens has been mentioned a few times earlier this year https://www.canonrumors.co/tag/canon-rf-70-135mm-f-2l-usm-lens/ as well as a 14-28 f:2.0. Nothing much since then, maybe delays due to COVID disruptions.


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## tron (Sep 3, 2020)

Rivermist said:


> Well there are some interesting lenses such as the 28-70 f:2.0 (which can use the IBIS of R5 / R6), the 15-35 L f:2.8 which gets IS (with the EF mount only the f:4.0 has IS), ditto the 24-70 f:2.8 IS. The 70-200 f:2.8 IS is extraordinarily compact, not sure of course whether Canon could have produced the same lens in EF but chose to have all it's L lenses in 70-200 be internal focusing only. The 35mm f:1.8 is interesting because the large glass is camera-side and the front lens is small, contrary to the EF 35mm f:2.0 (not quite sure what to make of that, but interesting). I am personally waiting for the 70-135mm L f:2.0, as far as I know nothing similar in EF. To your point I think that the benefits of RF in terms of optical design decrease as one goes to longer telephoto lenses, with only the electronics of RF (4 additional pins, faster data transfers, interaction of IBIS and lens IS) and a slightly wider diameter allowing for some innovation. The biggest difference s of course the distance to sensor, without a mirror the glass can extend closer to the sensor. It is surprising that more wide angle lenses have not come out yet because that is where I would expect the RF to deliver a bigger impact, e.g. for the successor to the 11-24mm, or a 14mm / 17mm / 20mm prime (the latter two were present in the FD lineup but never had an EF equivalent).
> _If the “back focus” distance between a lens’ rear element and the camera’s sensor is too far, the light entering the rear element is condensed and is harder to do aberration correction on. Lenses counteract this by making the front element (and whole lens) larger and bulkier. But by moving the rear element closer to the sensor (i.e. a short back focus), Canon spreads out the light rays passing through the rear element, making it easier to reduce aberration. _(https://petapixel.com/2019/06/17/canon-this-is-why-rf-lenses-are-outstanding/). Does this answer your question (full disclosure I am just a camera enthusiast, not an optical engineer).


RF 15-35 2.8L IS yes and I got it but Tamron has already IS so it can be done in EF mount
RF 24-70 2.8 L IS ditto for Tamron in EF mount and Nikon in F mount (the 24-70 2.8E VC)

The 15-35 is NO better than 16-35 2.8L III (and unfortunately It has the same vignetting)

The 50 1.2 and 85 1.2 are definitely better in RF version but the EF versions were very old designs so I believe Canon could improve them if they wanted to.

Canon EF L lenses were/are very good so to me it is the trend that makes them go to the mirrorless direction.


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## Franklyok (Sep 4, 2020)

Rivermist said:


> This 70-135 f:2.0 lens has been mentioned a few times earlier this year https://www.canonrumors.co/tag/canon-rf-70-135mm-f-2l-usm-lens/ as well as a 14-28 f:2.0. Nothing much since then, maybe delays due to COVID disruptions.



It must be very well hidden patent. Looking forward to end of 2020.


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## DennisHuiberts (Sep 7, 2020)

Rivermist said:


> Well there are some interesting lenses such as the 28-70 f:2.0 (which can use the IBIS of R5 / R6), the 15-35 L f:2.8 which gets IS (with the EF mount only the f:4.0 has IS), ditto the 24-70 f:2.8 IS. The 70-200 f:2.8 IS is extraordinarily compact, not sure of course whether Canon could have produced the same lens in EF but chose to have all it's L lenses in 70-200 be internal focusing only. The 35mm f:1.8 is interesting because the large glass is camera-side and the front lens is small, contrary to the EF 35mm f:2.0 (not quite sure what to make of that, but interesting). I am personally waiting for the 70-135mm L f:2.0, as far as I know nothing similar in EF. To your point I think that the benefits of RF in terms of optical design decrease as one goes to longer telephoto lenses, with only the electronics of RF (4 additional pins, faster data transfers, interaction of IBIS and lens IS) and a slightly wider diameter allowing for some innovation. The biggest difference s of course the distance to sensor, without a mirror the glass can extend closer to the sensor. It is surprising that more wide angle lenses have not come out yet because that is where I would expect the RF to deliver a bigger impact, e.g. for the successor to the 11-24mm, or a 14mm / 17mm / 20mm prime (the latter two were present in the FD lineup but never had an EF equivalent).
> _If the “back focus” distance between a lens’ rear element and the camera’s sensor is too far, the light entering the rear element is condensed and is harder to do aberration correction on. Lenses counteract this by making the front element (and whole lens) larger and bulkier. But by moving the rear element closer to the sensor (i.e. a short back focus), Canon spreads out the light rays passing through the rear element, making it easier to reduce aberration. _(https://petapixel.com/2019/06/17/canon-this-is-why-rf-lenses-are-outstanding/). Does this answer your question (full disclosure I am just a camera enthusiast, not an optical engineer).



Thanks for the explanation. It makes a lot more sense now. As far as I understand is that the enhancements by the RF mount mostly result in increased image quality. About that RF 70-200mm, the fact that it is a pumper zoom put me off from it. Had the Nikon 200-500mm F5.6 which is a pumper zoom as well and it got quite dirty inside when you use it a lot outdoors. The possibility of placing larger elements more to the back with the RF mount makes me quite interested in what a RF 400mm F2.8 or 600mm F4 can shave off in weight. Both Sony and Canon have managed to shave quite some weight off of their latest super long telephotos by placing the elements more to the back and therefore be able to shrink them quite significantly.


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