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RF 50mm f1.8 stm review.

Started Dec 29, 2020 | Discussions
Swerky Contributing Member • Posts: 793
RF 50mm f1.8 stm review.
1

The digital picture have finished the review of the RF 50mm 1.8. Wasn't the larger mount diameter supposed to bring, among other things, less vignette to the image? Perhaps I'm wrong.
https://www.the-digital-picture.com/Reviews/Lens-Vignetting-Test-Results.aspx?FLI=0&API=0&FLIComp=0&APIComp=0&Lens=1528&Camera=1508&LensComp=989

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Karl_Guttag Senior Member • Posts: 1,883
Re: RF 50mm f1.8 stm review.
1

Swerky wrote:

The digital picture have finished the review of the RF 50mm 1.8. Wasn't the larger mount diameter supposed to bring, among other things, less vignette to the image? Perhaps I'm wrong.
https://www.the-digital-picture.com/Reviews/Lens-Vignetting-Test-Results.aspx?FLI=0&API=0&FLIComp=0&APIComp=0&Lens=1528&Camera=1508&LensComp=989

I think that was the technical reason they gave for the RF mount over say Sony's E mount.  But then it seems all the canon lenses, even the L-lenses have significant vignetting without any digital correction (seems to get mentioned in every technical review). I don't think any of the vignetting is being caused by the diameter of the opening, but more a factor of the lens design.

At the same time, there is amazing little chroma aberrations after correction. I wonder if these issues are linked. It feels like the Canon designers are designing lenses with correction expected. The let parameters go that can be corrected in software. Of course, correction comes at some cost.

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R2D2 Forum Pro • Posts: 26,531
Re: RF 50mm f1.8 stm review.
6

Swerky wrote:

Wasn't the larger mount diameter supposed to bring, among other things, less vignette to the image?

Only when the lens design utilizes that advantage, as in the new RF 35mm f/1.8...

New RF 35 f/1.8 design on right.

However the new RF 50mm f/1.8 didn't incorporate a lot of that...

RF 50 f/1.8

Images courtesy TDP.

R2

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shawnphoto Senior Member • Posts: 1,307
Re: RF 50mm f1.8 stm review.

Swerky wrote:

The digital picture have finished the review of the RF 50mm 1.8. Wasn't the larger mount diameter supposed to bring, among other things, less vignette to the image? Perhaps I'm wrong.
https://www.the-digital-picture.com/Reviews/Lens-Vignetting-Test-Results.aspx?FLI=0&API=0&FLIComp=0&APIComp=0&Lens=1528&Camera=1508&LensComp=989

Welcome to the brave new world.

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moon1029 Regular Member • Posts: 304
Re: RF 50mm f1.8 stm review.
2

Karl_Guttag wrote:

Swerky wrote:

The digital picture have finished the review of the RF 50mm 1.8. Wasn't the larger mount diameter supposed to bring, among other things, less vignette to the image? Perhaps I'm wrong.
https://www.the-digital-picture.com/Reviews/Lens-Vignetting-Test-Results.aspx?FLI=0&API=0&FLIComp=0&APIComp=0&Lens=1528&Camera=1508&LensComp=989

I think that was the technical reason they gave for the RF mount over say Sony's E mount. But then it seems all the canon lenses, even the L-lenses have significant vignetting without any digital correction (seems to get mentioned in every technical review). I don't think any of the vignetting is being caused by the diameter of the opening, but more a factor of the lens design.

At the same time, there is amazing little chroma aberrations after correction. I wonder if these issues are linked. It feels like the Canon designers are designing lenses with correction expected. The let parameters go that can be corrected in software. Of course, correction comes at some cost.

I think that's a lens design trend rather than for technical reason. The EF 16-35 f/2.8L III has far more vignetting than the II version, and the RF 15-35 and EF-16-35 f/2.8L III are similar in this deparment. Canon's engineers are probably trading sharpness and contrast for vignetting.

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moon1029 Regular Member • Posts: 304
Re: RF 50mm f1.8 stm review.
1

shawnphoto wrote:

Swerky wrote:

The digital picture have finished the review of the RF 50mm 1.8. Wasn't the larger mount diameter supposed to bring, among other things, less vignette to the image? Perhaps I'm wrong.
https://www.the-digital-picture.com/Reviews/Lens-Vignetting-Test-Results.aspx?FLI=0&API=0&FLIComp=0&APIComp=0&Lens=1528&Camera=1508&LensComp=989

Welcome to the brave new world.

The vignetting looks serious on the test chart. In real world use, with the low noise performance of R5/R6 at ISO as high as 25600 that's not a problem. Even after peripheral correction there is no visible noise in the corners. That's my experience with the RF 35mm f/1.8, which also has heavy vignetting on test charts.

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OP Swerky Contributing Member • Posts: 793
Re: RF 50mm f1.8 stm review.

moon1029 wrote:

Karl_Guttag wrote:

Swerky wrote:

The digital picture have finished the review of the RF 50mm 1.8. Wasn't the larger mount diameter supposed to bring, among other things, less vignette to the image? Perhaps I'm wrong.
https://www.the-digital-picture.com/Reviews/Lens-Vignetting-Test-Results.aspx?FLI=0&API=0&FLIComp=0&APIComp=0&Lens=1528&Camera=1508&LensComp=989

I think that was the technical reason they gave for the RF mount over say Sony's E mount. But then it seems all the canon lenses, even the L-lenses have significant vignetting without any digital correction (seems to get mentioned in every technical review). I don't think any of the vignetting is being caused by the diameter of the opening, but more a factor of the lens design.

At the same time, there is amazing little chroma aberrations after correction. I wonder if these issues are linked. It feels like the Canon designers are designing lenses with correction expected. The let parameters go that can be corrected in software. Of course, correction comes at some cost.

I think that's a lens design trend rather than for technical reason. The EF 16-35 f/2.8L III has far more vignetting than the II version, and the RF 15-35 and EF-16-35 f/2.8L III are similar in this deparment. Canon's engineers are probably trading sharpness and contrast for vignetting.

I don't know if vignetting is related to sharpness and contrast, but yes as you mentioned the EF 16-35 II has noticeably less vignetting than the third version, thus vignette is not only related to mount diameter and the lens design that takes advantage of that. Although I haven't checked in what area the 16-35 III is better than the II.

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RDM5546
RDM5546 Senior Member • Posts: 3,654
Re: RF 50mm f1.8 stm review.
2

Swerky wrote:

moon1029 wrote:

Karl_Guttag wrote:

Swerky wrote:

The digital picture have finished the review of the RF 50mm 1.8. Wasn't the larger mount diameter supposed to bring, among other things, less vignette to the image? Perhaps I'm wrong.
https://www.the-digital-picture.com/Reviews/Lens-Vignetting-Test-Results.aspx?FLI=0&API=0&FLIComp=0&APIComp=0&Lens=1528&Camera=1508&LensComp=989

I think that was the technical reason they gave for the RF mount over say Sony's E mount. But then it seems all the canon lenses, even the L-lenses have significant vignetting without any digital correction (seems to get mentioned in every technical review). I don't think any of the vignetting is being caused by the diameter of the opening, but more a factor of the lens design.

At the same time, there is amazing little chroma aberrations after correction. I wonder if these issues are linked. It feels like the Canon designers are designing lenses with correction expected. The let parameters go that can be corrected in software. Of course, correction comes at some cost.

I think that's a lens design trend rather than for technical reason. The EF 16-35 f/2.8L III has far more vignetting than the II version, and the RF 15-35 and EF-16-35 f/2.8L III are similar in this deparment. Canon's engineers are probably trading sharpness and contrast for vignetting.

I don't know if vignetting is related to sharpness and contrast, but yes as you mentioned the EF 16-35 II has noticeably less vignetting than the third version, thus vignette is not only related to mount diameter and the lens design that takes advantage of that. Although I haven't checked in what area the 16-35 III is better than the II.

I think the lenses are designed with greater consideration for the corrected image quality and less consideration for the pixel peeping in RAW images.   Their goal being to further distance them and their imaging performance from the camera evaluation metrics used by customers of the encroaching hordes making  smartphone alternatives.  Greater computational enhancement in camera using AI software in-camera and during post processing is the future of photography and video media creation.

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Claire Dupuis Senior Member • Posts: 1,917
Re: RF 50mm f1.8 stm review.
7

Swerky wrote:

The digital picture have finished the review of the RF 50mm 1.8. Wasn't the larger mount diameter supposed to bring, among other things, less vignette to the image? Perhaps I'm wrong.
https://www.the-digital-picture.com/Reviews/Lens-Vignetting-Test-Results.aspx?FLI=0&API=0&FLIComp=0&APIComp=0&Lens=1528&Camera=1508&LensComp=989

I LOVE vignetting in a lens, I find modern optics clear edge to edge wide open sad enough to make me cry. A little darkened corners give depth and character to a lens, I'm so glad this one exhibits some !

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sobrien
sobrien Senior Member • Posts: 1,756
Re: RF 50mm f1.8 stm review.
3

Swerky wrote:

The digital picture have finished the review of the RF 50mm 1.8. Wasn't the larger mount diameter supposed to bring, among other things, less vignette to the image?

The RF mount diameter isn’t larger than the EF one.

The RF flange distance is shorter, though, which I understand means light hitting the sensor at more oblique angles which I believe could contribute to the greater vignetting, though I stand to be corrected on that by someone who understands this stuff better than I do.

Perhaps I'm wrong.
https://www.the-digital-picture.com/Reviews/Lens-Vignetting-Test-Results.aspx?FLI=0&API=0&FLIComp=0&APIComp=0&Lens=1528&Camera=1508&LensComp=989

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Karl_Guttag Senior Member • Posts: 1,883
Flange distance and Sensor Illumination Angles

sobrien wrote:

Swerky wrote:

The digital picture have finished the review of the RF 50mm 1.8. Wasn't the larger mount diameter supposed to bring, among other things, less vignette to the image?

The RF mount diameter isn’t larger than the EF one.

The RF flange distance is shorter, though, which I understand means light hitting the sensor at more oblique angles which I believe could contribute to the greater vignetting, though I stand to be corrected on that by someone who understands this stuff better than I do.

Perhaps I'm wrong.
https://www.the-digital-picture.com/Reviews/Lens-Vignetting-Test-Results.aspx?FLI=0&API=0&FLIComp=0&APIComp=0&Lens=1528&Camera=1508&LensComp=989

It is a very interesting question as to how much the illumination angle of the sensor affects the vignetting. A simple sensor illuminated at an oblique angle would be expected to have vignetting effects in the corners, Things like microlenses on the sensor would help but not eliminate the issue.

I'm don't know what The Digital Picture is doing to test the Lens. It looks like they are using some kind of lab equipment and not just taking pictures with the camera for the vignetting image.

It would be interesting if some cameras/sensors exhibit more or less vignetting with the same lens.

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shawnphoto Senior Member • Posts: 1,307
Re: RF 50mm f1.8 stm review.
2

Claire Dupuis wrote:

Swerky wrote:

The digital picture have finished the review of the RF 50mm 1.8. Wasn't the larger mount diameter supposed to bring, among other things, less vignette to the image? Perhaps I'm wrong.
https://www.the-digital-picture.com/Reviews/Lens-Vignetting-Test-Results.aspx?FLI=0&API=0&FLIComp=0&APIComp=0&Lens=1528&Camera=1508&LensComp=989

I LOVE vignetting in a lens, I find modern optics clear edge to edge wide open sad enough to make me cry. A little darkened corners give depth and character to a lens, I'm so glad this one exhibits some !

I find heavy vignette to be the realm of cornball photography. A small amount of vignette is pleasant and adds a subtle depth to the image. 1-2 stops max in the corners. Even then it will look stupid against a clear sky and require removal.

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tkbslc Forum Pro • Posts: 17,522
Re: RF 50mm f1.8 stm review.
1

Swerky wrote:

The digital picture have finished the review of the RF 50mm 1.8. Wasn't the larger mount diameter supposed to bring, among other things, less vignette to the image? Perhaps I'm wrong.
https://www.the-digital-picture.com/Reviews/Lens-Vignetting-Test-Results.aspx?FLI=0&API=0&FLIComp=0&APIComp=0&Lens=1528&Camera=1508&LensComp=989

The mount diameter is the same as EF.

axlotl Senior Member • Posts: 2,273
Re: RF 50mm f1.8 stm review.

R2D2 wrote:

Swerky wrote:

Wasn't the larger mount diameter supposed to bring, among other things, less vignette to the image?

Only when the lens design utilizes that advantage, as in the new RF 35mm f/1.8...

New RF 35 f/1.8 design on right.

However the new RF 50mm f/1.8 didn't incorporate a lot of that...

RF 50 f/1.8

Images courtesy TDP.

R2

I have both RF 50mm f1.8 and RF 35mm f1.8 and they each exhibit substantial corner shading of similar degree despite their different approaches to lens design.

Andrew

axlotl Senior Member • Posts: 2,273
Re: RF 50mm f1.8 stm review.
1

Swerky wrote:

The digital picture have finished the review of the RF 50mm 1.8. Wasn't the larger mount diameter supposed to bring, among other things, less vignette to the image? Perhaps I'm wrong.
https://www.the-digital-picture.com/Reviews/Lens-Vignetting-Test-Results.aspx?FLI=0&API=0&FLIComp=0&APIComp=0&Lens=1528&Camera=1508&LensComp=989

R5, 50mm f1.8 at f11  hand held.

That review is thorough as  usual from Bryan Carnarthan. However I think he ends up underselling the lens a bit, I wonder if he got a slightly-not-quite-up-to spec copy ?

His copy did not show sharp corners until f11. Mine is sharp in the corners from f4-f5.6. He also describes the lens as being suitable for "beginners and kids..." My experience is that it can deliver very high levels of image detail  on the R5 and is entirely suitable for enthusiast and/or professional use.

Andrew

R2D2 Forum Pro • Posts: 26,531
Re: RF 50mm f1.8 stm review.

axlotl wrote:

R2D2 wrote:

Swerky wrote:

Wasn't the larger mount diameter supposed to bring, among other things, less vignette to the image?

Only when the lens design utilizes that advantage, as in the new RF 35mm f/1.8...

New RF 35 f/1.8 design on right.

However the new RF 50mm f/1.8 didn't incorporate a lot of that...

RF 50 f/1.8

Images courtesy TDP.

R2

I have both RF 50mm f1.8 and RF 35mm f1.8 and they each exhibit substantial corner shading of similar degree despite their different approaches to lens design.

Andrew

I own both also, and the 50 exhibits more vignetting than the 35 (they’re indeed both pretty heavy). The 35 also has better corners overall. Maybe there’s copy variation, but my observations line up with those from TDP.

R2

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pawn Veteran Member • Posts: 3,261
Re: RF 50mm f1.8 stm review.
1

Swerky wrote:

The digital picture have finished the review of the RF 50mm 1.8. Wasn't the larger mount diameter supposed to bring, among other things, less vignette to the image? Perhaps I'm wrong.
https://www.the-digital-picture.com/Reviews/Lens-Vignetting-Test-Results.aspx?FLI=0&API=0&FLIComp=0&APIComp=0&Lens=1528&Camera=1508&LensComp=989

Thanks Swerky for sharing

I know that vignetting can be corrected in software.  What are issues in doing this correction in software?  Some people even add some vignettes to their images.

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R2D2 Forum Pro • Posts: 26,531
Re: RF 50mm f1.8 stm review.
1

pawn wrote:

Swerky wrote:

The digital picture have finished the review of the RF 50mm 1.8. Wasn't the larger mount diameter supposed to bring, among other things, less vignette to the image? Perhaps I'm wrong.
https://www.the-digital-picture.com/Reviews/Lens-Vignetting-Test-Results.aspx?FLI=0&API=0&FLIComp=0&APIComp=0&Lens=1528&Camera=1508&LensComp=989

Thanks Swerky for sharing

I know that vignetting can be corrected in software. What are issues in doing this correction in software? Some people even add some vignettes to their images.

It can add noise and/or lead to loss of detail (no free lunch).  It also takes more time and processing cycles.

R2

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OP Swerky Contributing Member • Posts: 793
Re: RF 50mm f1.8 stm review.
1

Claire Dupuis wrote:

Swerky wrote:

The digital picture have finished the review of the RF 50mm 1.8. Wasn't the larger mount diameter supposed to bring, among other things, less vignette to the image? Perhaps I'm wrong.
https://www.the-digital-picture.com/Reviews/Lens-Vignetting-Test-Results.aspx?FLI=0&API=0&FLIComp=0&APIComp=0&Lens=1528&Camera=1508&LensComp=989

I LOVE vignetting in a lens, I find modern optics clear edge to edge wide open sad enough to make me cry. A little darkened corners give depth and character to a lens, I'm so glad this one exhibits some !

True vignette can be attractive in some cases, but it is nevertheless a flaw, and removing it in post introduces noise. Specially against the sky, noise can be pretty obvious the more the vignette is heavy.

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quiquae Senior Member • Posts: 2,265
Re: RF 50mm f1.8 stm review.

R2D2 wrote:

pawn wrote:

Swerky wrote:

The digital picture have finished the review of the RF 50mm 1.8. Wasn't the larger mount diameter supposed to bring, among other things, less vignette to the image? Perhaps I'm wrong.
https://www.the-digital-picture.com/Reviews/Lens-Vignetting-Test-Results.aspx?FLI=0&API=0&FLIComp=0&APIComp=0&Lens=1528&Camera=1508&LensComp=989

Thanks Swerky for sharing

I know that vignetting can be corrected in software. What are issues in doing this correction in software? Some people even add some vignettes to their images.

It can add noise and/or lead to loss of detail (no free lunch). It also takes more time and processing cycles.

R2

The processing cost is negligible--it's just one of many corrections that go into RAW processing. The noise problem is real, though.

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