EF vs RF 50 1.8 STM MTF chart comparison

[stevelee]

The old 50 1.4 was one of Canon's 'misses', hopefully, if we se an RF replacement, they can make it a 'hit' this time round.

I see a lot of negative comments on this lens, but have not found anything to dislike about it. Perhaps it is because I used it as my portrait lens for my Rebel. If the corners were not sharp, that was a feature and not a bug. The background was blurry anyway from my choosing f/1.4 or f/2. Maybe if the center is not hypersharp, I could have taken that as making the portrait a bit more flattering. Since I have been shooting full frame, I have not had much occasion to use it. I was shooting a small group in a relatively low light setting, so I chose that lens. In retrospect, I could have stopped down slightly more, as one teen as standing slight farther back and was not quite as sharp as the others. But I see that more as a problem with the user rather than the lens.

So what is so bad about that lens? I’m curious, not that the answer will make me use it any more or even less.

 

[LogicExtremist]

I see a lot of negative comments on this lens, but have not found anything to dislike about it. Perhaps it is because I used it as my portrait lens for my Rebel. If the corners were not sharp, that was a feature and not a bug. The background was blurry anyway from my choosing f/1.4 or f/2. Maybe if the center is not hypersharp, I could have taken that as making the portrait a bit more flattering. Since I have been shooting full frame, I have not had much occasion to use it. I was shooting a small group in a relatively low light setting, so I chose that lens. In retrospect, I could have stopped down slightly more, as one teen as standing slight farther back and was not quite as sharp as the others. But I see that more as a problem with the user rather than the lens.

So what is so bad about that lens? I’m curious, not that the answer will make me use it any more or even less.

I suspect it got a bad reputation is because of its performance wide open and at brighter apertures, but there's a bit more to it.

To quote the DPR lens review:

Canon EF 50mm F1.4 USM review

The EF 50mm F1.4 USM is Canon's mid-level offering in a range stuffed full of 50mm primes, covering all budgets from the ultra-cheap 50mm F1.8 mkII through to the stratospherically-priced 50mm F1.2 L USM. Although it was introduced in June 1993, fully seven years after the birth of the EOS...

www.dpreview.com

Conclusion - Pros

Excellent image quality when stopped down
Essentially no lateral chromatic aberration
Fast and accurate autofocus with full-time manual override

Conclusion - Cons

Distinctly soft and 'dreamy' at wider apertures (F1.4-F1.8)
Bokeh chromatic aberration, most visible at wide apertures
Vignetting at wide apertures on full frame (essentially disappears by F2.8)
Somewhat susceptible to flare


Looking at the TDP review:

Canon EF 50mm f/1.4 USM Lens Review

Is the Canon EF 50mm f/1.4 USM Lens right for you? Learn all you need to know about the Canon EF 50mm f/1.4 USM Lens in The-Digital-Picture.com's review!

www.the-digital-picture.com

"The 50 f/1.4 finds a home with many photographers - from pro to casual - for several reasons.

The first reason for the popularity of this Canon lens is image quality.

Although it is soft wide open, the Canon EF 50mm f/1.4 USM Lens is sharp at f/2 and very sharp when stopped down to f/2.8 or narrower. Corners are soft until f/2 for 1.6x FOVCF bodies and f/2.8 on full frame bodies. Strong halation is present at f/1.4 (a soft, dreamy look) with some CA (Chromatic Aberration). Colors and contrast (after the halation diminishes at f/2 or so) are very nice. The 50 f/1.4's 8-blade aperture creates a good foreground/background blur quality. Light fall-off is noticeable through f/2 on a Full Frame body, When mounted on a 1.6x FOVCF body, light fall-off is noticeable only through f/1.6 or so. My exposures with this lens run about 1/3 stop brighter than with most of my other lenses."


The reviews look fairly good. The real reason why the lens gets a bad rap is value for money. To keep things in perspective, this lens was released in 1993. To quote the DPR review - "Although it was introduced in June 1993, fully seven years after the birth of the EOS system, it can actually trace its roots back much earlier, being based on the classic manual focus FD 50mm F1.4 design of 1971."

The cheaper 50mm lens at the time was the Canon EF 50mm f/1.8 II, and people back then were asking how much more the EF 50mm f/1.4 was offering considering its much higher cost.

When the Canon EF 50mm f/1.8 STM was released in 2015 (22 years after the release of the f/1.4 lens), with its low price, improved IQ over the previous budget nifty-fifties, and better build quality, it was considered excellent value for money, which made the higher priced but much older f/1.4 lens harder to justify for the money.

This might be justification for not buying the lens (because there may be better value-for-money options) many years after its release date, but that's no reason to not use it if you already have it, and don't have a better compact 50mm!

 

[SwissFrank]

And Canon has to use double gaussian design for the 50mm f/1.8 because...?

I think, because it's so compact? The new-school designs (like the new Nikon 50/1.8, RF 50/1.2, Leica APO ASPH 50/2, Otus whatever it is) are all 2-5x bigger volume than the double Gaussian.

I don't know that there's not any "new" design that would be as compact/cheap/light as the double Gauss, but just knowing corporations, if there was anything with better IQ, or smaller/cheaper/lighter than the double G SOMEONE would be making it. And I see no such thing.

 

[SwissFrank]

It would be nice if tests yielded consistent results!

Thanks again, LogicExtremist!

THIS test matches exactly what I expected. On this test, to my eye the RF 1.2 totally beats the RF 1.8 both at f/2.0 and wide open even though its a full stop faster (f/1.2 vs. f/1.8). If you took the 50/1.8 instead of the 50/1.2, you'd be kicking yourself for the rest of your life over the lost sharpness.

Meanwhile vs. the 24-105/4, the RF 50/1.8, at least, isn't worse IQ than the zoom, and may be a bit better, at f/4, and gives you 2 1/3 more stops if you want it. It also has the same 26-27mm aperture so the bokeh is comperable in amount to the 24-105/4 at 105mm. In short, if you leave the house with the 50/1.8 purely for portability purposes (I like to have a camera in my backpack) at least you won't be sacrificing sharpness and bokeh amount at the same time you're sacrificing zoomability.

I should probably pick up the 50/1.8 basically to use as a compact/portable 24-105/4, not a compact/portable 50/1.2, which it is totally crushed by in terms of image quality (based on this second test site you reference).

 

[SwissFrank]

The cheaper 50mm lens at the time was the Canon EF 50mm f/1.8 II, and people back then were asking how much more the EF 50mm f/1.4 was offering considering its much higher cost.

When the Canon EF 50mm f/1.8 STM was released in 2015 (22 years after the release of the f/1.4 lens), with its low price, improved IQ over the previous budget nifty-fifties, and better build quality, it was considered excellent value for money, which made the higher priced but much older f/1.4 lens harder to justify for the money.

When EF mount came out in 1987, Canon wanted pros to use the f/1.0 (astigmatic as hell) or the f/1.8 "MkI" as I call it. I felt this was a marketing/business decision, given how simple, and well-researched, a 50/1.4 would have been. I think they hoped people would rather compromise "up" by buying the f/1 lens than compromising "down" to get the f/1.8.

They F I N A L L Y came out with the f/1.4 six years later, at which point the 50/1.8 MkII came out, super-decontented (plastic everything including mount if I recall correctly). Both pros and financially-comfortable amateurs would use the 50/1.4, while the MkII 1.8 was for really budget-conscious customers.

(Similarly they had the excellent-sharpness-and-bokeh-but-horrible-literally-everything-else 85/1.2, or non-USM 85/1.8. I envied Nikon users their 85/1.4 and finally we got one for Canon.)

So I got the 50/1.8 MkI used and paid nearly a 50/1.4 price for it. Except for the 5-sided diagram, it seemed usefully smaller than the 50/1.4 and I used it quite a bit: any time I was leaving the house and not planning on taking photos, I'd take the camera with the 50/1.8.

I never looked at the final 50/1.8. My understanding is that all EF 50/1.8's had the exact same glass in them but maybe the 50/1.8 had substantially better coatings?

I also picked up the 50/1.2 but probably used it for less than 100 or so shots, but also stopped using my 50/1.4 too. Strangely I stuck mostly with the MkI until selling most of my EF outfit when I bought the R.

 

[Antono Refa]

I think, because it's so compact? The new-school designs (like the new Nikon 50/1.8, RF 50/1.2, Leica APO ASPH 50/2, Otus whatever it is) are all 2-5x bigger volume than the double Gaussian.

I don't know that there's not any "new" design that would be as compact/cheap/light as the double Gauss, but just knowing corporations, if there was anything with better IQ, or smaller/cheaper/lighter than the double G SOMEONE would be making it. And I see no such thing.

IIRC, when the the uber-fifties were released (Nikon AF-S NIKKOR 58mm f/1.4G, Sigma 50mm f/1.4 ART, ZEISS Otus 55mm f/1.4, etc), some forums members explained those were sharp because they were designed as medium telephoto lenses, and pickle jars because, given the flange distances, that meant they also had to be retrofocal.

So, with the RF's short flange distance, shouldn't Canon be able to make a 50mm lens designed like a medium telephoto, but EF 85mm f/1.8 size & weight, rather than uber fifties size & weight.

 

[stevelee]

...

Conclusion - Cons

Distinctly soft and 'dreamy' at wider apertures (F1.4-F1.8)
Bokeh chromatic aberration, most visible at wide apertures
Vignetting at wide apertures on full frame (essentially disappears by F2.8)
Somewhat susceptible to flare


Looking at the TDP review:

Canon EF 50mm f/1.4 USM Lens Review

Is the Canon EF 50mm f/1.4 USM Lens right for you? Learn all you need to know about the Canon EF 50mm f/1.4 USM Lens in The-Digital-Picture.com's review!

www.the-digital-picture.com

"The 50 f/1.4 finds a home with many photographers - from pro to casual - for several reasons.

The first reason for the popularity of this Canon lens is image quality.
...

When the Canon EF 50mm f/1.8 STM was released in 2015 (22 years after the release of the f/1.4 lens), with its low price, improved IQ over the previous budget nifty-fifties, and better build quality, it was considered excellent value for money, which made the higher priced but much older f/1.4 lens harder to justify for the money.

This might be justification for not buying the lens (because there may be better value-for-money options) many years after its release date, but that's no reason to not use it if you already have it, and don't have a better compact 50mm!

Thanks. That makes sense. The vignetting didn’t show up on my Rebel. The bit of softness wide open was a virtue not a vice for my usage. The lens didn’t cost a lot by the time I bought it. So the cons were real enough, but just didn’t much apply to me.

 

[Sporgon]

I never looked at the final 50/1.8. My understanding is that all EF 50/1.8's had the exact same glass in them but maybe the 50/1.8 had substantially better coatings?

also…..

With the 50 STM Canon claimed “optimal placement” of the lenses. Having used one I think they succeeded with this, as they are doing with more recent lenses, and that’s the main reason it’s better than the II in the centre when shot wide open. Sharpness still drops off dramatically mid frame, but doesn’t alter the fact you can still make world class images with it.

 

[SwissFrank]

IIRC, when the the uber-fifties were released (Nikon AF-S NIKKOR 58mm f/1.4G, Sigma 50mm f/1.4 ART, ZEISS Otus 55mm f/1.4, etc), some forums members explained those were sharp because they were designed as medium telephoto lenses, and pickle jars because, given the flange distances, that meant they also had to be retrofocal.

So, with the RF's short flange distance, shouldn't Canon be able to make a 50mm lens designed like a medium telephoto, but EF 85mm f/1.8 size & weight, rather than uber fifties size & weight.

The group of lenses you cite as uber-fifties were SLR lenses?

I think the new lenses in the family I'm talking about (RF 50/1.2, Nikon's new 50/1.8, Leica's new APO ASPH 50/2) are fresh, computer-generated designs that don't owe much if anything to previous generations of medium teles.

And yes, you don't need retrofocus on mirrorless/rangefinder bodies. Canon aren't morons: they're not going to have the brains to develop a new lens like this yet be so stupid as to forget to remove a retrofocus group or something like that.

 

[SwissFrank]

With the 50 STM Canon claimed “optimal placement” of the lenses. Having used one I think they succeeded with this, as they are doing with more recent lenses, and that’s the main reason it’s better than the II in the centre when shot wide open. Sharpness still drops off dramatically mid frame, but doesn’t alter the fact you can still make world class images with it.

1) why wouldn't the elements have been optimally placed before? 2) how can you tell from using a lens that the elements are "optimally placed?"

I think the phrase you're referring to is just marketing nonsense. The elements have always been placed optimally.

The three EF 50/1.8's indeed have identical optics.

Here's the 50mm f/1.8 MkI (the pro-quality built one), from https://global.canon/en/c-museum/product/ef259.html



Here'e the 50mm f/1.8 MkII (the plastic consumer one):



Here's the EF 50/1.8 STM: https://global.canon/en/c-museum/product/ef451.html

"In addition to maintaining the proven optical design of its predecessor, the new prime lens employs a lens coating that is optimized for shooting with digital cameras to minimize the occurrence of ghosting and flare. Furthermore, it includes a 7-bladed aperture—an improvement over the previous model’s 5-bladed aperture"

 

[Antono Refa]

The group of lenses you cite as uber-fifties were SLR lenses?

I think the new lenses in the family I'm talking about (RF 50/1.2, Nikon's new 50/1.8, Leica's new APO ASPH 50/2) are fresh, computer-generated designs that don't owe much if anything to previous generations of medium teles.

No, I'm not referring to any of those. As I wrote, I'm referring to the Nikon AF-S NIKKOR 58mm f/1.4G, Sigma 50mm f/1.4 ART, ZEISS Otus 55mm f/1.4, and possibly a couple more released at the time. Note two of them have a stated focal length slightly longer than 50mm.

 

[Sporgon]

1) why wouldn't the elements have been optimally placed before? 2) how can you tell from using a lens that the elements are "optimally placed?"

I think the phrase you're referring to is just marketing nonsense. The elements have always been placed optimally.

The three EF 50/1.8's indeed have identical optics.

Here's the 50mm f/1.8 MkI (the pro-quality built one), from https://global.canon/en/c-museum/product/ef259.html

View attachment 201397

Here'e the 50mm f/1.8 MkII (the plastic consumer one):

View attachment 201398

Here's the EF 50/1.8 STM: https://global.canon/en/c-museum/product/ef451.html

"In addition to maintaining the proven optical design of its predecessor, the new prime lens employs a lens coating that is optimized for shooting with digital cameras to minimize the occurrence of ghosting and flare. Furthermore, it includes a 7-bladed aperture—an improvement over the previous model’s 5-bladed aperture"

View attachment 201399

1) Poor assembly / tolerances. You don’t think that the lenses we buy for the price we pay are all perfectly assembled do you ? Far from it, hence why we get copy to copy variation.
2) Improved performance over the older versions despite using exactly the same lens formula.

Actually I don’t think it is marketing BS. Nor does Roger Cicala from Lens Rentals. If you search it on his blog I think you’ll find he had some observations regarding the matter.

 

[Nemorino]

1) why wouldn't the elements have been optimally placed before?

The RF has the focussing close to the sensor and the EF at the front.

Lens design comparison: Canon EF 50mm f/1.8 STM and the Canon RF 50mm f/1.8 STM

Here is a lens diagram comparison between the EF 50mm f/1.8 STM and the upcoming Canon RF 50mm f/1.8. The new RF 50mm f/1.8 STM definitely looks like a brand

www.canonrumors.com

This is a benefit of the shorter flange distance.