# Optical Limits reviews Canon RF 15-35mm f/2.8 USM L IS



## AlanF (Mar 31, 2020)

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Canon RF 15-35mm f/2.8 USM L IS - Review / Test Report


Canon RF 15-35mm f/2.8 USM L IS - Review / Test Report




www.opticallimits.com




Superb image quality, extreme vignetting.


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## Viggo (Mar 31, 2020)

Thanks for sharing  yup, the vignetting is ridiculous for lens at this price point, no two ways about it...

I have tried it and it wasn’t as crazy as I expected, but I shot in a well lit store and at low iso so the files turned out okay. But any higher than 200 iso and this is a dealbreaker for me. Such a shame really...


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## SteveC (Apr 1, 2020)

Viggo said:


> Thanks for sharing  yup, the vignetting is ridiculous for lens at this price point, no two ways about it...
> 
> I have tried it and it wasn’t as crazy as I expected, but I shot in a well lit store and at low iso so the files turned out okay. But any higher than 200 iso and this is a dealbreaker for me. Such a shame really...



We are likely going to see more and more lenses that rely on the EVF to mask optical imperfections, since the camera will do the same thing. This is something new to an all-electronic (no optical viewfinder) camera; it could not have been done before.


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## privatebydesign (Apr 1, 2020)

SteveC said:


> We are likely going to see more and more lenses that rely on the EVF to mask optical imperfections, since the camera will do the same thing. This is something new to an all-electronic (no optical viewfinder) camera; it could not have been done before.


And the cameras are going to cook the 'RAW' files so you can't ever not see the lens aberrations, Canon already do it with the P&S's and Nikon do it with the Z's, I'm sure they aren't alone.


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## SteveC (Apr 1, 2020)

privatebydesign said:


> And the cameras are going to cook the 'RAW' files so you can't ever not see the lens aberrations, Canon already do it with the P&S's and Nikon do it with the Z's, I'm sure they aren't alone.



And you know, I can live with that for lower-tier cameras. Part of the price you pay for economy is lower intrinsic quality.

But now there's the RF 24-240 that couldn't be released without a firmware upgrade first...because it has horrific vignetting and barrel distortion at the shorter end, and so the camera had to be trained to hide it. If that were the alternative I had (and no, it isn't; plenty of others) I'd keep my 18-200 Tamron for the EF-M, which I'm pretty confident doesn't resort to such monkeyshines (why would Canon help Tamron sell lenses?). Yes, its crop frame which makes the job easier (barrel distortion gets worse as the projected image gets wider), but I doubt such distortion could be hidden even in a crop size. (And it's even an 11+:1 zoom versus 10:1.)


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## privatebydesign (Apr 1, 2020)

SteveC said:


> And you know, I can live with that for lower-tier cameras. Part of the price you pay for economy is lower intrinsic quality.
> 
> But now there's the RF 24-240 that couldn't be released without a firmware upgrade first...because it has horrific vignetting and barrel distortion at the shorter end, and so the camera had to be trained to hide it. If that were the alternative I had (and no, it isn't; plenty of others) I'd keep my 18-200 Tamron for the EF-M, which I'm pretty confident doesn't resort to such monkeyshines (why would Canon help Tamron sell lenses?). Yes, its crop frame which makes the job easier (barrel distortion gets worse as the projected image gets wider), but I doubt such distortion could be hidden even in a crop size. (And it's even an 11+:1 zoom versus 10:1.)


Well RAW cooking is going to come more and more prevalent, unfortunately. A sure benefit of MILC's, and progress.....


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## Deleted member 381342 (Apr 1, 2020)

privatebydesign said:


> Well RAW cooking is going to come more and more prevalent, unfortunately. A sure benefit of MILC's, and progress.....



If the end file looks good, I don't think I am going to mind. And as long as the end result is still real, multiple exposures to make a cleaner picture are a-ok with me(like a phone), but I draw the line when it is trying to digitally make the out of focus area smoother than the lens can produce so that it looks like a better lens.


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## koenkooi (Apr 1, 2020)

Codebunny said:


> If the end file looks good, I don't think I am going to mind. And as long as the end result is still real, multiple exposures to make a cleaner picture are a-ok with me(like a phone), but I draw the line when it is trying to digitally make the out of focus area smoother than the lens can produce so that it looks like a better lens.



I'd still like the RAW to be, well, RAW and have DPP/LR/C1/etc do the cooking.


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## Del Paso (Apr 1, 2020)

koenkooi said:


> I'd still like the RAW to be, well, RAW and have DPP/LR/C1/etc do the cooking.


ME TOO !


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## koenkooi (Apr 1, 2020)

Del Paso said:


> ME TOO !



Don't get me wrong, I run every picture taken with a Canon lens through DPP+DLO, so I don't mind digital corrections, but DPP/LR have an actual update cycle, the camera firmware not so much. I can DLO pictures from my 1D, 20D and 7D in DPP!


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## Antono Refa (Apr 1, 2020)

privatebydesign said:


> And the cameras are going to cook the 'RAW' files so you can't ever not see the lens aberrations, Canon already do it with the P&S's and Nikon do it with the Z's, I'm sure they aren't alone.



A camera can cook back the 4.5 stops of light fall off in the corners so one can't ever see it?


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## privatebydesign (Apr 1, 2020)

Antono Refa said:


> A camera can cook back the 4.5 stops of light fall off in the corners so one can't ever see it?


Yes it can, it can do it to any camera in playback mode but if your camera has an EVF it can do it in the 'viewfinder' live feed too. Now many might say 'so what?' and most of the time I could agree, but if you are chasing the highest IQ you can then having the corners of your image already lifted 4 stops to 'correct' for the lens really starts to limit the artistic choices you have with that file. Personally one of the things I have liked about Canon has been their comparatively unfettered RAW files, I believe MILC's and the keen competition in the sector are going to force this kind of jiggery pokery onto all the manufacturers.


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## brad-man (Apr 1, 2020)

I'll take my RAW over-easy while I wait for the f/4 version of the lens this thread was about...


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## Antono Refa (Apr 2, 2020)

privatebydesign said:


> Yes it can, it can do it to any camera in playback mode but if your camera has an EVF it can do it in the 'viewfinder' live feed too.



I was referring to how it would look on a computer screen or printed, rather than EVF or the camera's screen.



privatebydesign said:


> if you are chasing the highest IQ you can then having the corners of your image already lifted 4 stops to 'correct' for the lens really starts to limit the artistic choices you have with that file.



Exactly. If the sensor has 10 stops of dynamic range, and the lens has ~4 stops of vignetting at the corners, that will leave 6 stops of dynamic range in the corners, and cooking in the camera can't add two more.


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## privatebydesign (Apr 2, 2020)

Antono Refa said:


> I was referring to how it would look on a computer screen or printed, rather than EVF or the camera's screen.



It will look on a computer screen as it would look in the EVF or back screen on review, it is baked into the RAW file so you can't undo it even third party programs like Lightroom etc won't be able to 'undo' the bake.


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## Del Paso (Apr 2, 2020)

I can understand why heavy vignetting can be (is) an issue for many of us.
Less for me, since I'd be using an ultrawide almost exclusively at F.8 or less, and at low ISO, for landscape photography.
Yet, I still dislike manufacturers relying more and more often on software to "correct" optical defects, like vignette, distorsion, c.a. etc...
So, for now, I'll keep using my 16-35 F4 and EF 14 F2,8.


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## SecureGSM (Apr 2, 2020)

My EF 16-35/F2.8 III L with around 5 stops of vignetting in extreme corners isn't much better. Sony E 16-35/F2.8 GM is a much better vignetting controlled lens of course. I was thinking Sigma 14-24/F2.8 at some stage but there are issues as well: a softness at 24mm end, CA levels and pronounced focus shift









Canon EF 16-35mm f/2.8L III USM Lens Vignetting


Review vignetting (peripheral shading) test results with f-stop contours for the Canon EF 16-35mm f/2.8L III USM Lens. Compare the results from this lens with other lenses.




www.the-digital-picture.com


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## Antono Refa (Apr 2, 2020)

privatebydesign said:


> It will look on a computer screen as it would look in the EVF or back screen on review, it is baked into the RAW file so you can't undo it even third party programs like Lightroom etc won't be able to 'undo' the bake.



A back screen's resolution is ~3" diagonal and ~150K pixel, making it much easier to hide aberrations.


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## Quirkz (Apr 2, 2020)

SteveC said:


> And you know, I can live with that for lower-tier cameras. Part of the price you pay for economy is lower intrinsic quality.
> 
> But now there's the RF 24-240 that couldn't be released without a firmware upgrade first...because it has horrific vignetting and barrel distortion at the shorter end, and so the camera had to be trained to hide it. If that were the alternative I had (and no, it isn't; plenty of others) I'd keep my 18-200 Tamron for the EF-M, which I'm pretty confident doesn't resort to such monkeyshines (why would Canon help Tamron sell lenses?). Yes, its crop frame which makes the job easier (barrel distortion gets worse as the projected image gets wider), but I doubt such distortion could be hidden even in a crop size. (And it's even an 11+:1 zoom versus 10:1.)



Despite the rf24-240 requiring in camera correction at the wide end, it’s still an excellent lens. Reasonable compromises vs great portability/range. 

There’s a lot of clickbait hate on the optical correction out there, but there are also more in depth reviews. Plus it’s wider than the tampon 18-200, 24 vs 28mm equivalent, which I prefer. 

Is it great? No. But it’s pretty damn good, and the wide angle distortion is less of an issue than people make it out to be.


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## AlanF (Apr 2, 2020)

It's pretty well inevitable with a short sensor-rear element distance that you will get heavy vignetting. The light from, for example, the extreme right of the rear element strikes the extreme left of the sensor at a very sharp angle. So you have to correct for it either electronically or physically. A flexible concave sensor would be one answer, but I think that would be rather too esoteric. These problems don't worry me as I mainly use telephotos and these have the rear elements well inside the lens. My Sony RX10IV gives excellent images despite heavy corrections for distortion and vignetting.


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## SecureGSM (Apr 3, 2020)

AlanF said:


> It's pretty well inevitable with a short sensor-rear element distance that you will get heavy vignetting. The light from, for example, the extreme right of the rear element strikes the extreme left of the sensor at a very sharp angle. So you have to correct for it either electronically or physically. A flexible concave sensor would be one answer, but I think that would be rather too esoteric. These problems don't worry me as I mainly use telephotos and these have the rear elements well inside the lens. My Sony RX10IV gives excellent images despite heavy corrections for distortion and vignetting.



The Sony E 16-35/F2.8 GM is also designed for a short sensor-rear element distance. and "only" 3.5 stops of vignetting in extreme corners. Uncorrected.. so..


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## joestopper (Apr 5, 2020)

AlanF said:


> __
> 
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> 
> ...



Vignetting appears the price to pay for IS ...


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## Chris.Chapterten (Apr 7, 2020)

I really hope the rumored 35mm f1.2 doesn't suffer from this level of vignetting


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## Viggo (Apr 7, 2020)

Chris.Chapterten said:


> I really hope the rumored 35mm f1.2 doesn't suffer from this level of vignetting


The RF50 has pretty severe vignetting, but only at infinity focus, so for normal distance shooting it’s just fine, the RF 85 is excellent with vignetting. So wider seems worse, so a 35 f1.2 might be pretty bad...


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## Chris.Chapterten (Apr 8, 2020)

Viggo said:


> The RF50 has pretty severe vignetting, but only at infinity focus, so for normal distance shooting it’s just fine, the RF 85 is excellent with vignetting. So wider seems worse, so a 35 f1.2 might be pretty bad...


I have the RF50mm and haven't found the vignetting to be as bad as I thought it would be. I never shoot at infinity focus so that may explain things, thanks for clarifying. 

If that is the case with the RF35 1.2 I wonder if it would be better to adapt the 35mm 1.4L ii instead? If they can match the vignetting of the RF50mm and not be any worse than that.. that would be fine by me... but I suppose it's looking unlikely


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## YuengLinger (Apr 8, 2020)

Chris.Chapterten said:


> I have the RF50mm and haven't found the vignetting to be as bad as I thought it would be. I never shoot at infinity focus so that may explain things, thanks for clarifying.
> 
> If that is the case with the RF35 1.2 I wonder if it would be better to adapt the 35mm 1.4L ii instead? If they can match the vignetting of the RF50mm and not be any worse than that.. that would be fine by me... but I suppose it's looking unlikely


The ef 35mm 1.4L II works and balances beautifully on the R.


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## mkamelg (Apr 8, 2020)

Viggo said:


> The RF50 has pretty severe vignetting, but only at infinity focus, so for normal distance shooting it’s just fine, the RF 85 is excellent with vignetting. So wider seems worse, so a 35 f1.2 might be pretty bad...



Loss of light in the frame corners in currently produced 35mm focal length lenses with autofocus, with aperture values f/1.2 and f/1.4.

Sigma Art 35mm f/1.2 DG DN Sony FE mount: 73% (−3.76 EV)

Sigma Art 35mm f/1.4 DG HSM Canon EF mount: 66% (−3.16 EV)

Tamron SP 35mm f/1.4 Di USD Canon EF mount: 66% (−3.13 EV)

Canon EF 35mm f/1.4L II USM: 64% (−2.95 EV)


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## Viggo (Apr 8, 2020)

mkamelg said:


> Loss of light in the frame corners in currently produced 35mm focal length lenses with autofocus.
> 
> Sigma Art 35mm f/1.2 DG DN Sony FE mount: 73% (−3.76 EV)
> 
> ...


Non of these are made for very short flange distance like the RF mount, so seeing the 1,4 mk II at three stops, I suspect a 1.2 RF version will have 5 stops, at least, which is just ridiculous.


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## Chris.Chapterten (Apr 9, 2020)

mkamelg said:


> Loss of light in the frame corners in currently produced 35mm focal length lenses with autofocus, with aperture values f/1.2 and f/1.4.
> 
> Sigma Art 35mm f/1.2 DG DN Sony FE mount: 73% (−3.76 EV)
> 
> ...


Very useful information, thanks for posting. If the RF 35mm really does have 5 stops of vignetting it definitely looks like an adapted 35mm 1.4L ii is the way to go!

Edit: just had a look at the RF 35mm 1.8 and that lens has 3.8 stops of vignetting at f1.8. What are the chances of the L version being better than that? I really hope it is!


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## SecureGSM (Apr 9, 2020)

Viggo said:


> Non of these are made for very short flange distance like the RF mount, so seeing the 1,4 mk II at three stops, I suspect a 1.2 RF version will have 5 stops, at least, which is just ridiculous.


The Sigma 35/1.2 DN is a Sony E mount lens. designed for a short flange distance with 3.76 stop of vignetting in extreme corners. However, it seems that Canon engineers being quite relaxed about their vignetting levels on RF mount.


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## Chris.Chapterten (Apr 9, 2020)

SecureGSM said:


> The Sigma 35/1.2 DN is a Sony E mount lens. designed for a short flange distance with 3.76 stop of vignetting in extreme corners. However, it seems that Canon engineers being quite relaxed about their vignetting levels on RF mount.


Does not correcting for vignetting improve the lens in other ways? Or do you think it is just down to a design flaw?


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## Viggo (Apr 9, 2020)

SecureGSM said:


> The Sigma 35/1.2 DN is a Sony E mount lens. designed for a short flange distance with 3.76 stop of vignetting in extreme corners. However, it seems that Canon engineers being quite relaxed about their vignetting levels on RF mount.


Thanks, I missed the one 

quite relaxed indeed...


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## Viggo (Apr 9, 2020)

Chris.Chapterten said:


> Does not correcting for vignetting improve the lens in other ways? Or do you think it is just down to a design flaw?


None of them, it’s due to extreme angles that ligh has to bend when the rear element is that close to the sensor.


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