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

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.
Depends on the camera and settings used. It can be resolved with exposure and aperture previews turned on in cameras that support this setting combo.
 
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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...
I wonder how many actual buyers read one or more reviews, dig deep into test chart results, etc. No real idea, but the #1 mirrorless lens on amazon.com is the RF 50/1.8, which Klaus gives 3 stars of 5. Heck, the #7 mirrorless lens on Amazon is the RF 75-300, and even Bryan's rose-colored glasses struggle to find the silver lining there – "...it is not a high-performing model. If you are severely budget-constrained or using the lens in a high risk scenario (such as use by the kids), this lightweight lens might be the right choice for you."

I think your initial point is spot on, most people first look at spec and cost and make a decision mainly based mainly on that. It bears repeating – those of us discussing camera gear on the internet are not representative of most buyers.
 
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Which Canon bodies stop down during AF?
The newer ones can be set to "Exposure Simulation + DOF preview" where they will stop down in live view. This resolves the issue of focus shift with the 45mm f/1.2, 100mm f/2.8 L, and other lenses by letting you focus at the desired aperture rather than wide open.

This appears to only be available on RF lenses (when I tried adapting EF glass the option is not available, however this may be limited to a selection of lenses).

Bodies with Exposure Simulation + DOF preview:
R1
R3
R5 II
R6 II
R7
R8
R10
R50

Bodies which do not have this feature:
R
RP
R5
Ra
R100

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.

Focus shift is a property of the lens design, not a production issue.

Portraits should be fine as the issue is only noticeable at close shooting distances.
 
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The newer ones can be set to "Exposure Simulation + DOF preview" where they will stop down in live view. This resolves the issue of focus shift with the 45mm f/1.2, 100mm f/2.8 L, and other lenses by letting you focus at the desired aperture rather than wide open.
ExpSim + DoF Preview is my usual setting. Agree that it does resolve the issue of focus shift, though FYI it does not always let you focus at the desired aperture because if you stop down far enough, the camera may need to open the aperture somewhat to allow enough light for AF. Focus shift is evident close to wide open, stop down enough and the increased DoF mitigates the issue.

Here's an example with the R1 and 28-70/2. Stopped way down from wide open, you can see it open the aperture briefly (not to wide open, just 'enough') just before the first AF confirmation beep. I then opened the aperture up a bit (not to wide open, but to an aperture where focus shift could be an issue if this lens exhibited it, which it doesn't) and there is no aperture change before the second AF confirmation beep.

View attachment Stop down focus.mov
 
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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. :unsure:


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
No personal experience - it is from a mix of different videos about that lens, from some technical reviews and the lens design which is of the (modified) double gaussian type.
In my opinion close to the old EF 1.4 50 which I own.

Here the link to the TDP comparison: https://www.the-digital-picture.com...meraComp=979&SampleComp=0&FLIComp=0&APIComp=0

Here the pages on canon.jp for both the RF 45 and the EF 50 which show the lens configuration:
https://personal.canon.jp/product/camera/rf/rf45-f12/spec

https://faq.canon.jp/app/answers/detail/a_id/105318/~/【交換レンズ】ef50mm-f1.4-usm-機種仕様
 
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I anguished long and hard about what to do regarding this lens.

In the end, the review by Christopher Frost decided me - I fall into the subset of users that have the original R5, and, as I understand it from his review this lens has a focussing issue on all Canon cameras of that age or earlier. I didn't want to be at the mercy of Canon for a firmware update that may never happen (and likely won't happen).

The other aspect was the fact that I already had (the excellent) Sigma 85mm 1.4 Art which I attach using the Meike drop-in filter EF-RF adapter. For me, going for the Sigma 50mm 1.4 Art was a no brainer when you look at the quality of that lens. Literally the only thing counting against the Sigmas is weight, which is a fair comment. I also found that the need for a VND filter when shooting at 1.4 outdoors is often unavoidable, so the drop in filter adapter provided a very neat solution for this - conveniently available across all EF lenses with no fuss.

Ultimately, I think I could live with all of the "issues" the 45mm has, except the focussing one which is a deal breaker in my case. A lot of people want the "character" of an older lens, and many folks including me often put a small vignette in their photos in post anyway, so a lot of these things really come down to a matter of taste.

Mark.
 
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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.
Pretty much all online reviews and information should be read with a grain of salt, so to speak. They are best viewed as entertainment, in my opinion, and not as serious research into making purchase decisions. When it comes to cameras and lenses, the reality is that they are all very good to excellent, they all can do the job (especially if you understand what job they are best suited for), and all differences are minor. Of course, any online reviewer who would say such a thing, would soon have nothing to say. So they must do the opposite, to stay relevant. Slight differences are exaggerated. Images, as you say, are evaluated in conditions that are nowhere near what any actual photographer would view them under. And, of course, there is always the fact that anyone can produce a blog, podcast or website with no actual expertise.
 
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"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.

we talked about that one actually. it's one of the few reviews that I think Klaus messed up on and got a bad lens copy. for bad copy / transport damage reasons yes, you should always take results that especially don't make sense against the MTF as suspect.


I'm not sure if we could use that judgment as much in early EF days, especially in film, but certainly in the age of mirrorless and automated manufacturing. IMO, MTF is a good "idiot check" against a lens copy issue.
 
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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.

1) we literally wrote the article the day after the lens was announced. I didn't realize we were supposed to transport a copy of the lens and physically test it before writing about it ;)
2) the MTF does atypically match on abberations, constrast and resolution - so if you are looking for clinical optical quality, it's a decent judge.
3) what artifical conditions? yes, the MTF is calculated in Canon's case but their elements and most lenses are manufactured by machines, not humans anymore; the odds that the MTF will match reality have a fairly strong correlation.

"color rendering, contrast, bokeh, distortion, autofocus behavior, and practical usability"

color rendering: Canon's coatings are well known at this time. One important point of coatings is to make color rendering consistent.
contrast: is literally exhibited by the 10lp/mm MTF line pairs
bokeh: can be more or less determined by the MTF.
autofocus behaviour: you don't know how STM, USM, or VCM works?

I know the style of shooting that the 45mm was for, and as I said in that article, I just don't it anymore - it's not for me.

I can easily make that determination from an MTF, and as I stated, there are some that will love this lens:

As many of you know, I’m pretty huge on the bang for the buck lenses, but this lens, I think, prioritizes “character” a little too much to make it a general-purpose lens that would have a greater utility. If you are the type of photographer who loves candid portraits, in the studio, or even street shooting, then this may be an incredibly wonderful bargain lens to add to your kit. For me, I don’t shoot those disciplines much anymore, and if I did want to have that option, I’d probably find the RF 50mm F1.8 STM perfectly suitable as a substitute at 50% of the price.

For those seeking to reclaim the magic of the Canon EF 50mm f1.2L USM in a lighter, smaller, and more modern lens, this is a lens absolutely for you.


And we wrote that before the reviewers released their full reviews on the lens, and I'm pretty sure our take was spot on.
 
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Has anyone compared the optical quality of the 45mm f/1.2 to the assorted inexpensive Chinese fast fifties? Aside from autofocus, is it clearly better than, e.g., the TTArtisan 50mm f/1.2, or others of that ilk?

(If nothing else, presumably having available digital lens corrections is an advantage.)
 
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Has anyone compared the optical quality of the 45mm f/1.2 to the assorted inexpensive Chinese fast fifties? Aside from autofocus, is it clearly better than, e.g., the TTArtisan 50mm f/1.2, or others of that ilk?

(If nothing else, presumably having available digital lens corrections is an advantage.)

you mean the cheap manual focus ones? alot of those chinese primes you can get for a dime a dozen, from a fun factor, they are great. I found some of the manual focus ones (7artisans in particular) to have odd lens layouts that would trip me up (aperture and focus dials switched from what we'd traditionally expect).
 
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