EF vs RF 50 1.8 STM MTF chart comparison

ctk

Refurb EOS R Kit
Mar 25, 2020
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According to Canon, the RF 50 1.8 is significantly softer than the EF 50 1.8 and RF 35 1.8.

EF vs RF (RF mirrored for comparison):

RFvsEF.png

35 1.8 below:

rf35mm_f18_macro_is_stm_mtf.gif


Admittedly the EF 50's chart seems incredibly optimistic, but if we compare it to the 35 it's basically softer across the entire frame. I will wait for reviews and more sample shots (there are some pretty limited ones here) but the more I see about this lens the less optimistic I am. May still replace my Sigma 50 EX but I've been mulling getting the Samyang 50 XP and I think this just pushed me over since I'm not in the RF 50 1.2's tax bracket. Also still holding out hope for the Samyang 45 1.8 to get ported over but w/e. Thought this would be useful to you guys
 
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ctk

Refurb EOS R Kit
Mar 25, 2020
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Update- Canon did update their MTF methodology. Here is an apples to apples comparison:

1604507198421.png

Really really marginal improvement, at least in MTF. Hopefully Canon managed to clean up the LoCA.
 
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koenkooi

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Stop following me! Lol. Updated.

I'm in a work meeting and have enough brain space left to read all the forums that talk about the RF50 I just pre-ordered :)
 
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Maximilian

The dark side - I've been there
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Update- Canon did update their MTF methodology. Here is an apples to apples comparison:
Thanks for sharing, ctk.
Really really marginal improvement, at least in MTF. Hopefully Canon managed to clean up the LoCA.
I didn't expect much more, so every little bit is welcome.
Esp. when you look a little bit away from the middle (eg. at "10") there is pretty much gained.
Keep in mind that this D. Gauss design is well known and pretty much exhausted in R&D.
That why the modern Sigma and RF and other 50 mm designs are much bigger and complex - and much more expensive ;)
 

Mt Spokane Photography

I post too Much on Here!!
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I'd have been disappointed if Canon made a $800 lens with a different design. They went for a very low cost lens that likely costs $40 to manufacture over one costing several times more. Its likely able to make use of the same machinery in Taiwan for making the EF50. They hope to churn out a million of these, and that means every penny is squeezed out of the cost.

Could this be a kit lens for the rumored new very low cost FF R body. It seems unlikely since consumers like the idea of zoom lenses. However, Canon does not yet have a pair of cheap kit lenses just the RF 24-105, no ultra cheap telephoto zoom. If Canon wants their new low cost FF body to end up in stores, they need ultra low cost kit lenses to keep the 2 lens kit price around $1500. So, is there a $400 RF100-300mm low priced zoom coming to put in kits?
 

ctk

Refurb EOS R Kit
Mar 25, 2020
65
68
I'd have been disappointed if Canon made a $800 lens with a different design.
Why do you think this is the only alternative? Canon made a much more complex 35 1.8 "Macro" for $450. A truly new and good 50 1.8 without the macro capability probably could have launched for about $300 (with a sale price of $250 or so), and actually would have been worth buying over an EF 50 STM + adapter.
 

LogicExtremist

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Sep 26, 2021
501
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I have both of these 50mm F/1.8 lenses. The build quality of the RF lens feels a bit better, but it costs a lot more, and only has one switch for function ring and manual focus selection. Filter thread RF 43mm vs EF 49mm.

From the tests I've seen the image quality of the two is almost the same. The RF is slightly better at the edges, and slightly better in the centre when wide open..

 
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LogicExtremist

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Many thanks for the link.

I was surprised by his description of the corner sharpness/contrast. I thought his test images showed a VERY notable improvement in the corners in sharpness and in coma, and if anything not quite the improvement in the center he described.

Well, I found this quite depressing. I was really hoping they'd have a considerable improvement here. I do understand they have to choose between a big heavy modern lens design with great sharpness (as the RF 50/1.2, Leica APO-ASPH 50/2, Otus and even Nikon 50/1.8), and the cheap and compact. But I guess if you care about sharpness more than size, you can just mount the 50/1.2 and shoot it at 1.8.

So I'm left wondering which direction they'll jump with a 50/1.4? Will it also be a near-copy of the relatively crap EF, as this 1.8 has shown to be? Will it be a new-school design like the RF 50/1.2 and Nikon 50/1.8? My hope is for a third approach: old-school design but cost-no-object, like the non-APO Leica M 50/2. Keep it light and compact but spend whatever you have to for IQ.

I'd also like to see a halo lens of 50/0.7. It needn't be cheap or common, instead it could be like the old 1200/5.6, almost more a lens to talk about than to own,
I think the RF 50 f/1.8 has a slightly different look from its EF counterpart. it seems to have more contrast overall. That's something I believe I also see with the RF 35 f/1.8 and 24-105 f/4 L lenses that I own, but I'm just speculating here. I bought the RF 50 f/1.8 secondhand, barely used, and I'm glad I did, it's good value for money. From f/2.0 and higher the images look excellent.

When it comes to the fancy 50mm lenses, the old EF 50 f/1.2 was expensive, and a big deal at the time, but compared to the RF 50 f/1.2 it's quite soft looking back. I got the Sigma 50mm f/1.4 Art lens way back then, almost as good, and much sharper than the EF 50 1.2, but lacking the 'look' that some want, for less than half the price. 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.

Right now, the whole Canon lens range is a bit of a mess, only overpriced top-tier or budget entry-level lens lines, with nothing in the middle. I reckon it will probably pay to wait, to see if Canon will finally fill the missing middle tier, or get out of the way and allow Sigma or another third-party to do so.
 
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LogicExtremist

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In my experience the RF 24-105 has the image quality of the EF MkII with the size of the far smaller EF MkI. The result is so good (and today's cameras so good in lower light thx to IS and low-noise sensors) that I've gone to using it as my go-to lens after shooting primes
Same here, totally agree, I now use the RF 24-105 F/4 L lens as go-to work lens because it's really sharp and produces great image quality.

From https://www.digitalcameraworld.com/reviews/canon-rf-24-105mm-f4-l-is-usm-review

vMg8XpDNmZFgu87BUA8ccf-970-80.png.webp


"Even wide open the RF 24-105mm is impressively sharp at all focal lengths and stays so up to f/11. The new Nikon Z 24-70mm is still the lens to beat for centre sharpness, but the Canon comes close for edge sharpness, despite its larger focal range."


Here's the RF 50mm f/1.8 for comparison.

From https://www.digitalcameraworld.com/reviews/canon-rf-50mm-f18-stm-review

5rcrWnQ2myRb4MGeP5vhj3-970-80.png.webp

"Centre sharpness is respectable wide open and at f/2, and by f/2.8 it's simply superb. These centre sharpness scores are actually comparable to the far pricier RF 50mm f/1.2! Corner sharpness is nothing special at larger apertures, but it gets much better if you stop down to f/4. A peculiarity with the lens is its mid-frame sharpness (the region surrounding the centre). With most optics, this area is usually softer than the centre, but sharper than the edges of frame. However, our RF 50mm f/1.8 sample was consistently softer in the mid-frame than at the edges, though the difference won't be very noticeable in real-world shooting."


How does the RF 50mm f/1.2 L lens compare?

From https://www.digitalcameraworld.com/reviews/canon-rf-50mm-f12l-usm-review

Uoz2ywxuTpVMEQAGFCopcf-970-80.png.webp

"It's usual for a lens to be this sharp at such a large maximum aperture, but the new RF-mount 50mm delivers great results right up to f/11, and maintains impressive edge sharpness, too."
 
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Antono Refa

EOS R
Mar 26, 2014
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Between the shorter flange distance and 60% markup, I expected Canon to improve IQ significantly.
 
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Antono Refa

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flange distance is a godsend wider than 50mm, but for the classic double-gaussian I don't think it helps much. If you look at the comparison of the lens shapes and locations, I think the designers could have easily put the same formula on the EF mount.
And Canon has to use double gaussian design for the 50mm f/1.8 because...?
 
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LogicExtremist

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LogicExtremist, thx for gathering all the graphs and posting them. I'm surprised it doesn't quite jive with my experiences though.

I love the RF 24-105 but if it's as sharp as my 50/1.2 in the center I had no idea at all. I always ranked the 24-105 as great but the 50/1.2 as superb.

And I found ALL the EF 50s to be only marginally usable*, and the graph of the 50/1.8 doesn't seem much better, so I'm shocked to see the RF 50/1.8 rated so highly,.

*Well I bought most of them when I shot with 1N and 1V and often on 1600 or push-processed 400, and all the 50s were as good as they needed to be for that film.
They use software to do the testing, not sure how it compares to real world use. According to the graphs, the RF 50mm f/1.8 is sharper at the centre then the f/1.2 L lens at f/4, and both of them as well as the RF 24-105mm f/4 L are equally sharp at f/5.6!

The TDP test contradicts this, using the R5, the RF 50mm f/1.8 appears less sharp at the centre then the f/1.2 L lens at f/4 and f5.6


On the EOS R, at f/5.6, there seems to be no difference in centre sharpness between the RF 24-105mm f/4 L and the Rf f/1.2 L lens:


It would be nice if tests yielded consistent results! :oops:
 
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stevelee

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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

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Sep 26, 2021
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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:


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:


"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! :)
 
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Antono Refa

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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

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...

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:


"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.
 
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Sporgon

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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.