The Story of the Canon RF 45mm f/1.2 STM: The Tale of Different Reviews

[Richard CR]

The Canon RF 45mm f/1.2 STM, which was announced towards the end of 2025, brought a fresh outlook to Canon's RF mirrorless system. With a price tag of about $469, this small lens (78 x 75mm, 346g) promised to deliver shallow depth of field, beautifully blurred backgrounds, and nighttime performance without the high-end price tag […]

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[mb66energy]

I bought the EF 50 1.4 just before this lens was announced. Fits better in my bunch of EF lenses and can be used with a variable ND adapter.
R7 destroys that lens wide open - on FF with 24MPix it is very usable wide open. What I like is that the older EF version has low distortion and moderate CAs without any correction.
Now about the RF 1.2 45: It is close to these older designs in IQ, suffers from strong distortion and it has AF which is not the case for 3rd party lenses, a huge advantage!
Now my opinion about IQ wide open etc:
If you can use f/2.8 or f/4.0 and the lens is sharp, contrasty, gives good colors you can use it for landscape, lots of portrait situations, nature, architecture.
With f/1.2 or f/1.4 you have the option for low DOF or night shots which are not accessible with e.g. a f/4 or f/2.8 zoom. Some degradation in sheer sharpness is traded in to get the photo which is not possible with f/4 or f/2.8.

 

[Maximilian]

I haven't yet had a personal experience with this lens.
I am considering to get it, knowing that its IQ is limited.
I am not using f/1.x that often to justify the prices of the much better L lenses.
It was clear to me from the start that its sharpness wide open would be only good in the center to mid frame.
It was clear to me that the bokeh wide open exhibits “cat's eye” corners.
I thought, Canon could do a bit more about aberrations.
I am sure, I'll have to take a personal look at it.

Now about the RF 1.2 45: It is close to these older designs in IQ, suffers from strong distortion and it has AF which is not the case for 3rd party lenses, a huge advantage!
Now my opinion about IQ wide open etc:
...

Just to make it clear for me:
Your opinion is based on hands on experience or theoretical thoughts form MTF and the reviews in the web?
Thanks in advance for your clarification

 

[Snapster]

I'm surprised more of the reviews didn't catch the focus shift issue. Or it could be a quality control issue because of the cheap price?

If you can't get eyes in perfect focus at f/1.4 - f/2 on an R5 autofocus, the lens is absolutely a no go.

 

[roby17269]

I have had the EF 50 1.2 and I would agree it was legendary... in a bad way.
I did not like it at all.
If this lens is similar, then it is a no-go, regardless of the price. If I wanted something soft and quirky I'd buy a lens baby...
The RF 50 1.2 (which I have) may be much more expensive and heavier, but it delivers with almost no compromises.

 

[Tom R5R7]

I happen to have both this new 45/1.2 STM and the old EF 50/1.2L. I haven't run a full battery of tests, but what I can say from my limited comparisons is that the RF 45 is the sharper of the two, especially at wider apertures. Just a sharper lens.

On the other hand, the old 50/1.2L produces a creamier, smoother bokeh regardless of the harshness of the background. It is essentially a portrait lens. So 2 different animals with a similar purpose, perhaps, but one is considerably less expensive than the other is (or rather, was).

If I wanted ultimate sharpness, I'd get either the RF 50/1.4 or RF 50/1.2L lens - both appear to be spectacularly sharp and very well designed. But for my purposes, what I have now (along with the inexpensive 50/1.8 RF) will do the trick. I lean in favor of the RF 45 because of its size and weight, but I can't really say that I don't like what the EF 50/1.2L does for me either.

On focus shift, I hadn't paid a lot of attention to this issue, but I will be. Since I have the older R5, I don't have the ability to use "Display simulation" or whatever setting it is that people use to force the lens to autofocus with a smaller aperture than f/1.2. Whether this is a problem or not will be the subject of future testing and comparison to manual focusing.

 

[Tom R5R7]

I do wonder, however, why Canon didn't just take the optical formula for the EF 50/1.2L and transform it to the RF mount, kind of like what some third party lenses have done. It would have been easy and the development costs are minimal - basically make the adapter part of the lens. Optical formula unchanged.

But then they'd have 2 50/1.2 lenses.

 

[Berowne]

My fast 50mm Prime for a very affordable price (600€), excellent optical performance but quite slow AF is a second hand Zeiss Milvus 50mm/ f1.4. Only downside is the weight ...

 

[PinholeR5]

I have had the EF 50 1.2 and I would agree it was legendary... in a bad way.
I did not like it at all.
If this lens is similar, then it is a no-go, regardless of the price. If I wanted something soft and quirky I'd buy a lens baby...
The RF 50 1.2 (which I have) may be much more expensive and heavier, but it delivers with almost no compromises.

I wasn't too impressed by the EF 50mm F1.2 either. I got it just a bit before the RF 45mm F1.2 came out.

I happen to have both this new 45/1.2 STM and the old EF 50/1.2L. I haven't run a full battery of tests, but what I can say from my limited comparisons is that the RF 45 is the sharper of the two, especially at wider apertures. Just a sharper lens.

On the other hand, the old 50/1.2L produces a creamier, smoother bokeh regardless of the harshness of the background. It is essentially a portrait lens. So 2 different animals with a similar purpose, perhaps, but one is considerably less expensive than the other is (or rather, was).

If I wanted ultimate sharpness, I'd get either the RF 50/1.4 or RF 50/1.2L lens - both appear to be spectacularly sharp and very well designed. But for my purposes, what I have now (along with the inexpensive 50/1.8 RF) will do the trick. I lean in favor of the RF 45 because of its size and weight, but I can't really say that I don't like what the EF 50/1.2L does for me either.

On focus shift, I hadn't paid a lot of attention to this issue, but I will be. Since I have the older R5, I don't have the ability to use "Display simulation" or whatever setting it is that people use to force the lens to autofocus with a smaller aperture than f/1.2. Whether this is a problem or not will be the subject of future testing and comparison to manual focusing.

I ended up with both lenses as well. I did a quick comparison (not very scientific) using an R5 II with a link to the CRAW files for those interested:

P

Post in thread 'A Look at the RF 45mm f/1.2 STM, it seems compact.'

Dec 7, 2025

Got the RF 45mm F1.2 last week. I had bought a used EF 50mm F1.2 a few weeks before the 45mm was announced (lucky me).

So I decided to do a bit of comparing the two. I used my R5 II (all in electronic shutter) fo comparing. Every time I try to do this, I gaine renewed respect for folks who do reviews online. Doing these comparisons is hard and labor intensive!!

My comparison is only loosely controlled and somewhat ad-hoc. However, for what it's worth, my overall feeling is:

- These lenses are much more similar than they are different.
- The RF 45mm F1.2 is sharper
- The EF 50mm...

• PinholeR5

• 

 

[noname]

An 80mm f/1.2 STM will be released within 2027.

 

[Del Paso]

"If you are looking to purchase a lens and you know you will demand the most out of its optical performance, OpticalLimits is really the place to go to see how it performs."(Quote)
OK, then, according to O.L, the RF 28-70 is absolutely miserable at 70mm (corners). TDP's "Optical Quality" results being also underwhelming at 28mm.
What or who shall I believe now? Meanwhile, many forum members or moderators seem to really like it...
Reliability of reviews, no matter by whom, is very relative.
I'll never base a buying decision on reviews, good or bad, but on my own testing of a rented lens with the option to buy it if satisfied.

 

[EricN]

I have had the EF 50 1.2 and I would agree it was legendary... in a bad way.
I did not like it at all.
If this lens is similar, then it is a no-go, regardless of the price. If I wanted something soft and quirky I'd buy a lens baby...
The RF 50 1.2 (which I have) may be much more expensive and heavier, but it delivers with almost no compromises.

The 45mm is a little closer to 35 by 5mm. It's not much, but at least it wasn't 55mm, right?

 

[DocInfoSci]

I'm always fascinated by the hate for the EF 1.2. What do people use it for and on which body that it becomes unfit for purpose? I use the EF 50 1.2 for portraits of people and animals. I have always loved the outcome. On an R6 it's great, and with DLO it's amazing. In my humble opinion and for my purpose, of course.

To the article's point, I love the fact that both types of reviews are available. I feel strongly that hardware should first be evaluated on the merit of the hardware, and then next on the merit of the purpose with the vendor's pipeline considered.

Why? Because it's nice to know a) what the software is doing for me, so that I can plan for it; and b) so that I know what I can expect in a nominal situation with all of the pipeline included. The fact that Canon's software portion of the pipeline might need to correct for a) 5 (!) stops of darkness on the edge (noise bump?) and potentially multiple planes of sharp focus (wavy field) is really important to know. But, just like the EF 1.2, at the end of the day a killer shot is a killer shot. If the 45mm gets me there...

 

[Exploreshootshare]

It's gotten to a point where I really despise all these online reviews. Pixel peeping and looking at 300% views... nobody ever does that in the real world... so why the heck base a lens purchase on that review? Not the mention the "so, the lens has two switches, an aperture ring..." bullshit nobody needs. Optical limits only tells me if a lens is "clinical sharp" or not, it doesn't tell me anything about how usable the images actually are.

Given that most images are viewed on smaller screens and most prints are smaller as well, the lenses should be evaluated in that regard. I recently made Christmas pics of my students (4th grade) in challenging lighting conditions with the 85mm F2. In Lightroom, some images looked "slightly blurry" or not perfectly sharp at 100-300%. The prints (20cm x 30cm which is 8x12 inches) turned out perfectly. One couldn't tell if anything wasn't sharp or "the edges fell apart". Good lenses don´t necessarily have to be super sharp and great at 300% crop.

I just wished lenses reviewers would acknowledge that fact. But I'm ultimately guessing, not clinging to test-charts and actually reviewing the lenses for the purposes they are made for and forming a judgment without intensive chart-testing would require a skill most reviewers don't have: knowing how to shoot and what to shoot.

Funnily, some of favorite lenses have gotten bad reviews such as the 85mm F2, 100-400mm F5.6-8 and RF 16mm F2.8. The 85mm was recommended to me by a people photographer on a German camera website and it is a bargain. The 100-400mm was recommended to me by AlanF (among others) here at CR and it is great. It even produces great images with the TC attached. The 16mm was praised by photographer who hikes in the alps and so far, almost every time I used it delivered. All recommendations came from photographers who actually used the lenses, know their value despite their caveats. But the caveats don´t really matter if know how to work around them or know how theses lenses were intended to be used.

 

[roby17269]

The 45mm is a little closer to 35 by 5mm. It's not much, but at least it wasn't 55mm, right?

I guess I just don't care

 

[Exploreshootshare]

I, of course, weighed in with the MTF inspection of this lens, and left the conclusion that it really depends on your use case for the lens. I personally wasn't a fan. […]

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Did you honestly base your opinion on solely on the MTF chart? I´m asking because it kinda sounds (reads) like it.
To me, that would be like judging a car for an article for a magazine by only looking at a picture of it. Take it out for a spin, would you please?!

Basing an opinion about a camera lens solely on an MTF is fundamentally flawed imo because an MTF chart measures only one narrow aspect of performance under artificial conditions or sometimes - afaik are just simple calculations. (not sure about the calculations part, I've read some contradicting information). Real-world image quality depends on many factors it can’t show—such as color rendering, contrast, bokeh, distortion, autofocus behavior, and practical usability.

Basing a lens purchase on chart testing alone is misguided imo because test charts evaluate lenses in controlled, artificial conditions that rarely reflect how they are actually used. Charts emphasize measurable sharpness and contrast at specific distances, but they ignore critical real-world factors such as rendering style, color and micro-contrast, flare behavior, bokeh, autofocus reliability, handling, and how the lens performs across varied lighting and subject matter. A lens that excels on a chart can still produce uninspiring images in practice, while one that tests “worse” may deliver more pleasing and usable results in real photography.

 

[AlanF]

Funnily, some of favorite lenses have gotten bad reviews such as the 85mm F2, 100-400mm F5.6-8 and RF 16mm F2.8. The 85mm was recommended to me by a people photographer on a German camera website and it is a bargain. The 100-400mm was recommended to me by AlanF (among others) here at CR and it is great. It even produces great images with the TC attached. The 16mm was praised by photographer who hikes in the alps and so far, almost every time I used it delivered. All recommendations came from photographers who actually used the lenses, know their value despite their caveats. But the caveats don´t really matter if know how to work around them or know how theses lenses were intended to be used.

I have all three of those! OL actually gives the RF 85mm/2 a highly recommended and 8.5/10 for optical quality. Even though they pan the 16mm, they have to admit "A 16mmm f/2.8 for this kind of money is an insane bargain even with the mentioned limitations." The RF 100-400mm gives best telephoto bang for the bucks of any telephoto and very decent quality.

 

[Exploreshootshare]

I´ve read the article a second time and I somehow get the feeling that something gets overlooked what a lot of customers want:
- First of all: they want lenses and cameras to fit their budget.
- furthermore, they want good, sometimes great images, that are better than their SP. Otherwise why buy a camera...
- secondly: they want creative control (not all, some just shoot in automode)

A lot of customers don't demand "clinically perfect" images and lenses. But most reviewers don't get that...

 

[EricN]

I guess I just don't care

Probably nobody cares...

 

[roby17269]

I'm always fascinated by the hate for the EF 1.2. What do people use it for and on which body that it becomes unfit for purpose? I use the EF 50 1.2 for portraits of people and animals. I have always loved the outcome. On an R6 it's great, and with DLO it's amazing. In my humble opinion and for my purpose, of course.

I used it for fashion portraiture but, imho, it did not hold a candle to the 85 1.2 II and, especially for the money, I found its performance unacceptable. Never understood the point of a 1.2L lens that was not useable at 1.2
Just to be clear, I absolutely do not mind you liking it, but I reserve my right to loathe it