Canon 50 1.2 vs Sigma 50 art specifically for low light photos

[YuengLinger]

Sarpedon, I'm very sorry to hear about your gear. :-[

Hector1970, glad you are not frustrated with yours.

Together, you are persuasive about the 50 1.2, but for every few stories like yours, I hear too many negative experiences.

I was wrong, earlier, to say I wouldn't touch it "with other people's money." I'd borrow one from somebody who has a known good copy and give it a whirl, but still might hold out, as eventually Canon will release some kind of update. Maybe.

 

[Larsskv]

Sarpedon, I'm very sorry to hear about your gear. :-[

Hector1970, glad you are not frustrated with yours.

Together, you are persuasive about the 50 1.2, but for every few stories like yours, I hear too many negative experiences.

I was wrong, earlier, to say I wouldn't touch it "with other people's money." I'd borrow one from somebody who has a known good copy and give it a whirl, but still might hold out, as eventually Canon will release some kind of update. Maybe.

I think may of the negative stories come from those who shoot it mainly at f1.2, where it is soft and has lots of chromatic aberration. At f2, unless you pixel peep in the corners (which usually are blurry) sharpness is very decent, and bokeh, color, contrast is beautiful.

 

[snoke]

...
to make long story short:

In relatively good light (7EV+ approx.) AF consistency is good on 6D and 5D III.
In low light (under 6EV) AF consistency on 5D III is poor.

My understanding is that the 6d centre AF point low light sensitivity (-3EV)is better than the same of the 5D III and this is likely the major cause of better Sigma 35 Art and 50 Art AF performance on 6D in low light.

Summary: in low light, you want use lens but camera not good enough. Still everyone blame lens.

 

[pixel8foto]

I'm curious to know hoe people feel about the Canon vs Sigma 50 specifically in reference to low light photos. I currently have the privilege to own both, but I feel kind of silly having two similar lenses, and I feel like one should go. I had the Sigma for a long time, but specifically in low light, I always felt like maybe I was missing something in not having the Canon. It's about a half stop faster, and has the advantage of being a first party lens, which might make a difference when you're pushing the autofocus system to its limits in low light.

I used both for a while last night in low light, and I'm not sure if I can make a conclusive judgment. It seems like the Canon was just a little more apt to lock on to focus in challenging conditions, which would make sense with the wider aperture and what I assume to be better communication between the camera and lens. The Canon is definitely not as sharp as the Sigma, but honestly this was kind of welcome in low light. With the Sigma, I am always obsessing over whether or not the lens was able to nail focus in low light. With the Canon, the whole lens is not all that sharp, so I feel like there's a little more margin for error as far as what's considered "nailing" focus. But, maybe that's more of a personal issue/preference rather than something I can fault the Sigma for. I can't legitimately call it out for being too sharp.

So, anyway, I'm still on the fence.

In short, I agree with a lot of your experience, particularly your observation that the Canon's relative softness serves to paper over the cracks if focus is a bit out.

I do a fair bit of low-light work and have used both these lenses a lot.

I started with the Sigma 50 1.4 Art then bought the Canon 50 1.2 in absolute frustration at the Sigma's wildly inconsistent focusing. It got so bad that I found myself overshooting and then editing to the most accurately focussed photos, rather than those with the best content.

For outright sharpness, lack of distortion, fidelity, the Sigma wins hands down and is great for getting in tight, what with its excellent close-focussing ability. But it is useless to me as it just does not hit even static subjects reliably, let alone tracking moving subjects well. It is particularly bad if the subject is loose in the frame, which (not a technical conclusion, just assumption through use), feels like a lens+camera communication issue. I mean I could point it at a static subject and focus with great care, it will indicate the area of the focus point has hit the subject bang on in the middle, yet still be nailing the wall several metres behind. This isn't a case of micro adjustment, it's just wild, all over the shop, totally inconsistent. I used it on a 6D, a 5D3 and a 1DX. Counter-intuitively it worked best on the 6D and then the 5D3 and worst on the 1DX. Again, I have no technical support for this statement but my gut feeling was the slower focussing speed and, what *felt* like more precise central focus point accuracy of the lower-end 6D, in particular, worked to overcome the limits of Sigma's reverse-engineered focus, when paired with the faster-focussing Canon bodies. Regardless, this experience applied in good and bad light with the obvious problem being it was harder to tell through the viewfinder if I was massively out in low light, compared to in bright light. I found the 35 Art similarly afflicted, again particularly if a subject is loose in a frame, while the 24 Art is more consistently accurate although, again, it worked better to focus more consistently on my 6D's centre point than on any focus point on my 5D3 or 1DX.

My suspicion is that, as each model has been released, Sigma have improved the autofocus performance in respect of the lens itself and also it's communication with the cameras - no idea if that's accurate, just how it's felt in use, over time. I no longer use my Sigma 50 and 35 at all, but their 24 is my go-to wide angle on a 5D4, every day.

So now, at 50mm, I use the Canon 1.2 - again, almost every day, frequently at f/1.2, (just because, why not) on a 5D4. I like it in part *because* of it's inadequacies compared to the Sigma - the heavy vignette, the weaker contrast and flare in direct light - I can predict the behaviour most of the time and play with it as a virtue, even though such distortions are, on paper, to the Canon's disadvantage. It suffers far more from fringing, which I don't like, but it focusses roughly right much more often than the Sigma and, as you point out, because of its relative softness wide open, it's not as obvious when it's a notch or two out compared to the ruthlessly sharp Sigma, so tolerable a lot more of the time and the results, because of its distortions, are prettier - and easily corrected if not desired.

 

[aceflibble]

If low-light is going to be the only or vast-majority use for the lens, the answer is a simple question of centre exposure vs overall frame.

The Sigma is t/1.8 and the Canon is t/1.5 for middle half transmission, with any given copy able to vary by +/-0.15 of a stop. Due to diminishing returns with light and digital sensors, this equates to 0.55 (+/-0.1) of a stop difference. If you're desperate for light, that roughly half-stop might make a huge difference.

However, the Sigma suffers from vignetting of roughly 1.5 stops in the corner quarters, while the Canon suffers vignetting of approximately 2.5 stops across the entire outer third. This means that although the Canon is getting more light to you in the centre a larger portion of the image is actually about half a stop darker than the Sigma.

So if all you care about is getting the cleanest image in the centre 1/3-1/2 of the image, go for Canon. If you want the overall frame to be more evenly clean, get the Sigma.


But that's only thinking about the light gathering capabilities. Bear in mind too that the Sigma has far less aberration and distortion and more precise manual focus, but also has slightly slower autofocus and that AF has also proven to be a hair more unreliable. (Not that the Canon's is fantastic for AF, either; frankly they both need an AF overhaul.) The Sigma should, hypothetically, be less prone to flare as well as providing slightly smoother and rounder out-of-focus highlighting, though in my use of both I've not noticed a difference in those regards. Most importantly for anyone with a higher-resolution body (5DS, 5DS R, 5D4) the Sigma is much sharper wide-open; the Canon only looks sharp at f/1.2 if you're using a lower-resolution body (in my experience, <16mp); for mid-resolution bodies (20-24mp, say) they're about even.
Finally, the Sigma is of course slightly bigger, heavier, and requires larger filters.

Personally, given the higher ISO performance of most cameras made in the last few years (including APS-C ones), I have preferred the Sigma. Bump up the ISO by 1/3rd of a stop and you won't really notice a difference in noise but your whole frame will be more consistently exposed, and of course aberration-free and flatter. When I used to use the Canon I was eternally battling to minimise that fringing and distortion, not to mention it's a much softer lens when used wide-open. (Hell, even some lucky copies of the Canon 50mm f/1.4 can be sharper wide-open than the 1.2L can be.)
I liked the Canon well enough back when I was using a 1Ds mkII (16mp and more limited in ISO and DR) but once I moved on to the 1Ds mkIII (21mp + the usual ISO and DR improvements) a year later, and the 5D mkIII after that, it really didn't seem so great any more. Its resolving capabilities didn't hold up to the potential of the new cameras unless it was stopped down to at least f/2.5. The lower noise of the new cameras helped mitigate that a little but then it became a question of why even bother; if you're shooting at f/2.5 then the cheaper Canon 50mms are identically as good and have faster AF, so you may as well use the f/1.4 or even f/1.8 if you're going to be stopping down anyway. Once I got the Sigma and used that for a week I sold the Canon f/1.2. Before companies like DxO had even confirmed my suspicions, it was immediately obvious the Sigma was all-round the better lens. It was sharper at f/1.4 than the Canon was at f/2 or faster and every other optical quality is better, too. The AF is a fraction worse but not enough to make a practical difference, and personally I prefer the better manual focusing enough to compensate for fractionally worse AF. Similarly, I can't say the difference in size or weight bothers me. (Though I do wish it was a 72mm filter.)

So, for 9/10 people, I'd say the Sigma is going to be the hands-down best option. But if you're one of the few special cases where all you care about is getting as much light as possible in to the centre of the frame and you don't care what you have to trade off for that, then the Canon still does have value. I'd also say the Canon is still great if you use an older, lower-resolution body, where the other optical differences will basically be invisible.


(For full disclosure: As it so happens, due to my preference for manual focus, I now relegate the Sigma 50mm only for faster-paced events where manually focusing may be too risky, and for all other times I use the Samyang 50mm f/1.4 [t/1.6] as I've found it to be optically even better than the Sigma and has a nicer focus ring, and I have a Mitakon 50mm f/0.95 [t/1.3] for the times when I really need absolutely all the light possible.)

 

[Hector1970]

I think in general you get a lot of negative comments from people whose poor technique and lack of patience and lack of skills in posing people is blamed on particular lens. Maybe some lens have a tolerance problem but in general if you can't take a good photography with a 50 1.2 you should take up something like fishing.

Sarpedon, I'm very sorry to hear about your gear. :-[

Hector1970, glad you are not frustrated with yours.

Together, you are persuasive about the 50 1.2, but for every few stories like yours, I hear too many negative experiences.

I was wrong, earlier, to say I wouldn't touch it "with other people's money." I'd borrow one from somebody who has a known good copy and give it a whirl, but still might hold out, as eventually Canon will release some kind of update. Maybe.