Review: Canon RF 16mm f/2.8 STM by Christopher Frost

Random Orbits

EOS 5D Mark IV
Mar 14, 2012
2,455
331
That would definitely be a cause for concern, even more so for photos than video. It would be interesting to see how much those software-corrected images would hold up to extensive post processing like what is usually done with landscape photos, to see how the details hold up or whether the images begin to fall apart and start producing artifacts more readily.
It depends on what you're comparing this to. It's a $300 lens. Yes, something like the RF 15-35 f/2.8L IS would be better, but that is over 2k. For absolute IQ, I'd choose the L lens, but this might come in handy if weight is a primary factor or for snapshots where the subject is in the center. If I'm trying to save weight, I might opt for the ultrawide zoom, the nifty fifty and a telephoto. Some my opt for this RF 16, a standard zoom and a telephoto. I do like that it's the same size as the RF 50 f/1.8.
 

BBarn

EOS M6 Mark II
Nov 2, 2020
69
54
If geometric distortion correction caused a substantial reduction in sharpness, the corners of the RF 14-35 (which requires substantial geometric correction) wouldn't be sharp. But they are. Easy peasy. Geometric distortion correction can be accomplished with relatively little negative impact to image sharpness. If you want to know why the RF 16 isn't sharp in the corners, look elsewhere.
 
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gruhl28

Canon 70D
Jul 26, 2013
175
63
That would definitely be a cause for concern, even more so for photos than video. It would be interesting to see how much those software-corrected images would hold up to extensive post processing like what is usually done with landscape photos, to see how the details hold up or whether the images begin to fall apart and start producing artifacts more readily.
It would also be interesting to know whether jpg's and Raws processed in DPP lose 29% of their pixels, or whether Canon is actually doing something to "construct" additional pixels, whether that is simple interpolation or AI.
 

Aussie shooter

https://brettguyphotography.picfair.com/
Dec 6, 2016
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For those doubting focus by wire with the 16/2.8, perhaps autofocus will work.

With my R5 I can autofocus on many stars with my 20/1.4 Sigma, 35/1.4 Tamron, 70-200/2.8 L IS, and my 31 year old 300/2.8 L. One needs to find a reasonably good star well above the horizon and it is a good idea to turn the lens to manual focusing once accurate auto focus has been achieved. I have accidentally pressed the focus button while astro photography was going on and had to start over again. Also, my M6 ii will autofocus the 22/2 on night skies.
I have the R6(which auto focuses at the same level as the R5) and absolutely get better focus by manually focusing while zoomed in ten times.
 

neuroanatomist

I post too Much on Here!!
CR Pro
Jul 21, 2010
26,049
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If I didn't have the EF lens, and I wanted the get a wide angle f/4 zoom, the 14-35mm is the only one available for the RF mount and I would consider it rather than invest in an old mount lens. The two considerations are value for money and image quality. If the IQ is suitable for your requirements, then it might be a matter of waiting till the Xmas or EOFY sales arrive!
I just sold my EF 16-35/4L IS.

The degree of cropping are reported for the 16/2.8 seems excessive, and given that it was an unsubstantiated comment on a review I take it with a large grain of salt. Regardless, to deliver the camera’s full resolution, the cropped images must be upscaled.

I also don’t find a comparison between two corrected profiles (Canon 14-35 vs Samyang 14) to be especially compelling. Distortion correction changes framing, and the degree to which distortion is corrected may differ between the profiles.

I am pretty sure that if Canon labels a lens 16mm or 14mm, the FoV delivered in the final images will be that. Keep in mind that focal length is specified at infinity focus. Since people testing for lens distortion aren’t using charts or walls large enough to fill the frame with the lenses focused at infinity, focus breathing must be considered. For example, the EF-S 18-200mm at the long end frames at ~150mm equivalent with a close subject, the EF 100/2.8L Macro frames like ~67mm at 1:1. The 16/2.8 probably has a fair bit of breathing, the 14-35 less so.

For me, an additional factor is the small size of the 14-35, compared to the 16-35/4 (with adapter). Also, the relevant comparison to me is both lenses at the wide end, so even if the 14-35 isn’t quite 14mm, it’s wider than 16mm, and smaller and lighter in my bag.

I ordered the RF 14-35, once it arrives I’ll run some comparisons, including vs my EF 11-24 for FoV.
 

LogicExtremist

Lux pictor
Sep 26, 2021
173
106
I just sold my EF 16-35/4L IS.

The degree of cropping are reported for the 16/2.8 seems excessive, and given that it was an unsubstantiated comment on a review I take it with a large grain of salt. Regardless, to deliver the camera’s full resolution, the cropped images must be upscaled.

I also don’t find a comparison between two corrected profiles (Canon 14-35 vs Samyang 14) to be especially compelling. Distortion correction changes framing, and the degree to which distortion is corrected may differ between the profiles.

I am pretty sure that if Canon labels a lens 16mm or 14mm, the FoV delivered in the final images will be that. Keep in mind that focal length is specified at infinity focus. Since people testing for lens distortion aren’t using charts or walls large enough to fill the frame with the lenses focused at infinity, focus breathing must be considered. For example, the EF-S 18-200mm at the long end frames at ~150mm equivalent with a close subject, the EF 100/2.8L Macro frames like ~67mm at 1:1. The 16/2.8 probably has a fair bit of breathing, the 14-35 less so.

For me, an additional factor is the small size of the 14-35, compared to the 16-35/4 (with adapter). Also, the relevant comparison to me is both lenses at the wide end, so even if the 14-35 isn’t quite 14mm, it’s wider than 16mm, and smaller and lighter in my bag.

I ordered the RF 14-35, once it arrives I’ll run some comparisons, including vs my EF 11-24 for FoV.
When you test your RF 14-35mm f/4, can you please compare the uncorrected and software corrected images to confirm the extent of cropping that occurs? Thanks :)
 

gruhl28

Canon 70D
Jul 26, 2013
175
63
EXIF data shows the corrected image sizes of both RAW and JPG (large) files taken with the RF 16mm f/2.8 match the full sensor pixel count.
Thanks. So the image is being upscaled. How is the sharpness before vs. after correction?
 

BBarn

EOS M6 Mark II
Nov 2, 2020
69
54
Here's a quick shot with an RP using the RF 16mm (processed in DPP).

IMG_2783s.jpg


I'm just getting started with PS Elements so I could easily be doing something wrong, but below are two lower right corner areas from the same pic. The first is a JPG from Canon DPP (which automatically applies distortion correction). The second is of the approximately the same area from Photoshop Elements (which was uncorrected). I assume the brightness/contrast/color differences are from the different JPG engines. I don't see much difference in sharpness, but I'll leave that to others.

DPP (corrected)
IMG_2783 corner 600 sq.JPG


Photoshop Elements (uncorrected)
IMG_2783pse no dist comp corner.jpg


Even though the 100% crops are of the same area, the DPP crop is 600x600 pixels, and the PSE crop is 433x433 pixels.
 
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Frodo

EOS RP
Nov 3, 2012
428
109
A DPReview subscriber (crusliq) posted some images taken with the RF 16mm on an EOS R. Although not shot at infinity they give a sense of the degree of correction undertaken to remove barrel distortion. All @ f/2.8.
The first is the uncorrected image 6720 x 4480 pixels
In the second I applied +100 distortion correction in Lightroom.
The third is cropped such that the full vertical image is retained. This is 4994 x 3329 pixels or 16.6 MP, compared to 30.1 MP for the uncorrected image.
While this may be okay for an R5, the R6 is left with a little more than 11MP before the image is upscaled. I presume that this also applies for in-Camera corrections.

eosr_rf16mm_f2.8.jpg
eosr_rf16mm_f2.8-2.jpg
eosr_rf16mm_f2.8-3.jpg
 
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HMC11

Travel
CR Pro
Sep 5, 2020
63
59
There's another review (https://admiringlight.com/blog/review-canon-rf-14-35mm-f-4l-is-usm/) which indicated that the distortion became mild to moderate by 16mm. Here's his take:

"Thankfully, the distortion is really only truly severe at the 14mm setting. By 15mm, there is still a lot of barrel distortion, and the image circle is just barely not large enough, but by 16mm, the distortion is only mild to moderate and there are no truly dark corners. The mild barrel distortion persists through about 20mm, but by 24mm, the lens is essentially distortion free, before exhibiting a slight pincushion distortion at 35mm. Despite the absolutely severe distortion shown at 14mm, for most of the range, distortion control is pretty good."

Treating this as essentially a ligher & smaller RF 16-35 f4 with the added bonus of fairly usable 14-15mm FoV images might make it easier to go for this lens.

Eagerly awaiting your test results.
 
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LogicExtremist

Lux pictor
Sep 26, 2021
173
106
A DPReview subscriber (crusliq) posted some images taken with the RF 16mm on an EOS R. Although not shot at infinity they give a sense of the degree of correction undertaken to remove barrel distortion. All @ f/2.8.
The first is the uncorrected image 6720 x 4480 pixels
In the second I applied +100 distortion correction in Lightroom.
The third is cropped such that the full vertical image is retained. This is 4994 x 3329 pixels or 16.6 MP, compared to 30.1 MP for the uncorrected image.
While this may be okay for an R5, the R6 is left with a little more than 11MP before the image is upscaled. I presume that this also applies for in-Camera corrections.

View attachment 201054 View attachment 201055 View attachment 201056
It looks like theres a definite crop, warping and upscaling required to deliver a usable software-corrected image on the RF 16mm f/2.8.
 

LogicExtremist

Lux pictor
Sep 26, 2021
173
106
I think I found the RF 16mm f/2.8 lens equivalent EF lens in terms of specs and performance, but it's an EF-S lens...

Canon RF 16mm F2.8 STM @ f/8 on an R5 vs Canon EF-S 10-18mm f/4.5-5.6 IS STM @ 10mm f/4.5 on a 7D Mark II

Equivalent focal length and aperture comparison, with a some very major advantages in favour of the RF lens - RF prime on 2020 release 45MP full-frame sensor vs EF-S zoomon 2014 release 20.2MP APSC sensor.


Even with this test skewed heavily in favour of the RF 16mm, can anybody spot a difference in image quality?
The centre sharpness is hard to call, may be sharper on the RF 16mm, mid-frame is a close call, but the EF-S lens appears to be sharper and have better contrast in the periphery to me. :oops:
 
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gruhl28

Canon 70D
Jul 26, 2013
175
63
A DPReview subscriber (crusliq) posted some images taken with the RF 16mm on an EOS R. Although not shot at infinity they give a sense of the degree of correction undertaken to remove barrel distortion. All @ f/2.8.
The first is the uncorrected image 6720 x 4480 pixels
In the second I applied +100 distortion correction in Lightroom.
The third is cropped such that the full vertical image is retained. This is 4994 x 3329 pixels or 16.6 MP, compared to 30.1 MP for the uncorrected image.
While this may be okay for an R5, the R6 is left with a little more than 11MP before the image is upscaled. I presume that this also applies for in-Camera corrections.

View attachment 201054 View attachment 201055 View attachment 201056
Wow, that's even more being cropped out than previously reported.
 

Czardoom

EOS RP
Jan 27, 2020
346
733
Wow, we probably have never seen such amazing analysis and page long essays regarding the auto-correction of a lens!

Thank goodness, as a photographer, all I care about is the final image. If the Digital Picture's Image comparison tool is reasonably accurate, and the corners are indeed considerably better than the EF 17-40L and not too much worse than the EF 16-35L, then that is good enough for me.

Just curious, but to all those that are despairing about the auto-correction, do you not do any distortion correction in post-processing? Keystone or perspective corrections? Do you ever use the new image enlarging programs (such as GigaPixel) or comands in Photoshop or any other software? Those enlargement programs or commands create a great deal of new pixels, does that mean you won't use them? Or does doing the same thing the camera does on your computer make you forget all about your concerns?
 
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RexxReviews

I'm New Here
Sep 3, 2021
23
14
Wasn't the RF mount supposed to allow easier engineering of better designs without these optical weaknesses? Watching this review, the way the focus sounds like the original nifty fifty... It feels like they just slapped this together for lowest possible cost.

Meanwhile, I'm kicking myself. Two years ago I had a chance to purchase a 24-70 F/4 for $550, and I thought... meh, that's kinda pricey. Now it's going for $1200 on ebay from reputable places. The 16-35 F/4 is also skyrocketing. Maybe supply disruptions are a part of this, but there's still so much demand in good EF lenses, and they're optically no worse than the RF versions. Is Canon leaving money on the table?
What do you consider "sky rocketing"? I just picked up another 16-34 f4 about a month ago for around $700 in mint condition, new its still at the same retail price of around 1099. I have purchased many of this lens in the last few years as its what we use on our real estate training cameras and the only time I've seen them under $600 were usually very heavily used lenses and every blue moon a good shaped one that someone was selling far lower than they realized on FB marketplace.
 

RexxReviews

I'm New Here
Sep 3, 2021
23
14
Wow, that's even more being cropped out than previously reported.
People are not taking in consideration that the lens is shooting much wider than 16mm so that the corrected version is at around 16mm. I have tested this against my 16-35 f4. The corrected RF16mm is even a tad wider than the 16mm of the 16-35
 

neuroanatomist

I post too Much on Here!!
CR Pro
Jul 21, 2010
26,049
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People are not taking in consideration that the lens is shooting much wider than 16mm so that the corrected version is at around 16mm. I have tested this against my 16-35 f4. The corrected RF16mm is even a tad wider than the 16mm of the 16-35
But if the RF 16/2.8 is giving you a much lower MP image that is then being upscaled, to me that's a concern.
 
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Frodo

EOS RP
Nov 3, 2012
428
109
Just curious, but to all those that are despairing about the auto-correction, do you not do any distortion correction in post-processing? Keystone or perspective corrections? Do you ever use the new image enlarging programs (such as GigaPixel) or comands in Photoshop or any other software? Those enlargement programs or commands create a great deal of new pixels, does that mean you won't use them? Or does doing the same thing the camera does on your computer make you forget all about your concerns?
That is the entire point. Take astro photography. This involves a lot of image manipulation, stacking, compositing. If I start with a 20 or 30 MP file that is "clean" out of the camera, I have much more scope for subsequent processing than one which has had such heavy preprocessing.
It is clear that I am asking more than this relatively cheap lens (its still USD500 in New Zealand) can deliver. Probably fine for lots of other photographers.