# Patent: Canon RF 15-35mm f/4L



## Canon Rumors Guy (Nov 26, 2020)

> Canon News has uncovered a patent for a lens that will surely be coming in the future from Canon. I have reported that a Canon RF 14-35mm f/4L IS USM was on the way. Perhaps the “14mm” was a type and it will in fact be 15mm at the wide end.
> This patent also includes an optical formula that has a wide end of 16mm.
> I suspect we’re going to see this lens or something very similar announced in 2021.
> 
> ...



Continue reading...


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## analoggrotto (Nov 26, 2020)

1. Canon is *******. 

2. I really thought they would give the F4L wide zoom some more reach. 

3. bet this will be another supercompact wonder


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## SV (Nov 26, 2020)

These f/4's are nice for travel and hiking, being lighter and smaller.


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## BeenThere (Nov 26, 2020)

The EF 16-35 f~4 is a joy to use. I will hang on to that one. Also, using the EF version permits the filter adapter to be used (Thinking NDs from Breakthrough).


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## blackcoffee17 (Nov 26, 2020)

Why almost every mirrorless lens is focus by wire? Is there any technical limitation for mirrorless?


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## fred (Nov 26, 2020)

So... no IS anymore?


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## usern4cr (Nov 26, 2020)

The 16-35 f4L patent mentions a 10.35mm  backfocus at max wide angle. Wow, that's sticking the lens edge half way past the mount towards the sensor. And you still have to have room for the 1st & 2nd mechanical shutter and housing mechanism! Sometimes I'm just amazed at what they can design & build.


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## koenkooi (Nov 26, 2020)

usern4cr said:


> The 16-35 f4L patent mentions a 10.35mm  backfocus at max wide angle. Wow, that's sticking the lens edge half way past the mount towards the sensor. And you still have to have room for the 1st & 2nd mechanical shutter and housing mechanism! Sometimes I'm just amazed at what they can design & build.



And an ND filter stack on the C70!


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## danfaz (Nov 26, 2020)

fred said:


> So... no IS anymore?


The 2.8 has IS, don't see why this wouldn't.


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## usern4cr (Nov 26, 2020)

koenkooi said:


> And an ND filter stack on the C70!


Yeah, I forgot about the ND filter stack. I wonder if there will be a restriction on the C70 (or others) regarding some R lenses with a very small back focus (eg 10mm) where the lens might hit it?


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## sanj (Nov 26, 2020)

Canon Rumors Guy said:


> Continue reading...


Been waiting for this!!! It will have IS


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## sanj (Nov 26, 2020)

blackcoffee17 said:


> Why almost every mirrorless lens is focus by wire? Is there any technical limitation for mirrorless?


What does 'focus by wire' mean, please?


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## usern4cr (Nov 26, 2020)

sanj said:


> What does 'focus by wire' mean, please?


Assuming this is one of those "lost in translation" issues: "Focus by wire" is just a rotating ring with high resolution encoders that the camera sense so that it can adjust the AF mechanism accordingly. It removes the complexity of a mechanical user focus mechanism which would interfere with the latest high-tech AF mechanisms. I think "focus by wire" is the best thing you can have, provided they can make it feel smooth with proper damping/resistance with the proper range of motion from near-to-far and making it as par-focal as possible when combined with the mechanical zoom often used. It's also best (IMHO) when it's a fixed (predictable) focus range instead of a continuously spinning +/- one, but I'm sure others will prefer the other.


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## Doug7131 (Nov 26, 2020)

blackcoffee17 said:


> Why almost every mirrorless lens is focus by wire? Is there any technical limitation for mirrorless?


Focus by wire is usually cheaper and less mechanically complex. It also gives more freedom to use multiple focus groups in the lens without having to worry about mechanically linking them all to a single control ring. A bonus is that it (potentially) allows the user to customise how the focus ring behaves.


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## ColinJR (Nov 26, 2020)

I too was hoping they could get down to 14mm for the f/4 version... Alas. 

Side note, does anyone know why the 15-35 2.8 is backordered everywhere, and maybe when they might be back in stock?


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## Andy Westwood (Nov 26, 2020)

I'd be interested a new RF wide lens, make it small and compact please Canon


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## Rocksthaman (Nov 26, 2020)

I’m really hoping for an RF 24-70 F4. 

I love the size on the EF version.


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## Mr Majestyk (Nov 26, 2020)

BeenThere said:


> The EF 16-35 f~4 is a joy to use. I will hang on to that one. Also, using the EF version permits the filter adapter to be used (Thinking NDs from Breakthrough).


Zero reason at all to update that beauty. I use it on my Sony A7RIII and won't be swapping it for any native options.


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## sanj (Nov 27, 2020)

Mr Majestyk said:


> Zero reason at all to update that beauty. I use it on my Sony A7RIII and won't be swapping it for any native options.


Ok. But the RF will be lighter, smaller and slightly better overall IQ. Your decision. For me, I will buy it.


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## Skyscraperfan (Nov 27, 2020)

15.45 and 16.48 are suspicious numbers. It seems Canon want to be able to round down and sell them as 15mm and 16mm. I always hate cheating like that. I am not a lens engenieer, but if you have a formula for a 15.45mm lens, it should be technically possible to tweak some parameters and make it exactly 15mm. The same is true at the long end of tele lenses, where Canon often rounds up. 

It is good though that Canon brings slower versions of its very expensive lenses with f/2.8. With a powerful IBIS you do not need much light and I usually chose an aperture just below the diffraction limit of the camera to get as much depth of field as possible. That's f/11 at my 18 megapixel camera. So f/2.8 for me is just something that makes a lens twice as heavy and twice as expensive and I only need it for low light hand held shots.


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## sanj (Nov 27, 2020)

Andy Westwood said:


> I'd be interested a new RF wide lens, make it small and compact please Canon


It should be compact!


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## Joules (Nov 27, 2020)

Skyscraperfan said:


> 15.45 and 16.48 are suspicious numbers.


The patent numbers and what it is marketed as always differ. And of course the marketing tends to be the more optimistic one.

None of your lenses are truly what is written on them.


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## VICYASA (Nov 27, 2020)

If this has IS... it's a buy!!


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## [email protected] (Nov 27, 2020)

danfaz said:


> The 2.8 has IS, don't see why this wouldn't.



Did a comparison of the RF 15-35 f/2.8 versus these new lens designs. They're about identical. This suggests that there would have to be two things to make that design work: IS and the UD elements required for the f/2.8 design. Implications: it will be spendy. The 16-35 version of the new patent is significantly smaller than the 15-35 version.


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