Capturing great images in very dark sceneries using a EOS R5 and a bright F/1.2 lens. Worth to buy a dedicated lens?


CR Pro
Dec 20, 2012
It's hard to be definitive about "almost as good". There are differences; you'll need to decide for yourself how important they are...

By any normal standard the optical performance of the Sigma Art is extraordinarily good - it was considered something of a sensation within the industry when it was launched. Speaking personally, it is not important to me that marginally better might be available elsewhere. However it might be important to you; some people prefer to know that they are using "the best". Or there may be reasons other than sharpness to prefer the Canon, such as bokeh or ergonomics.

If I remember correctly part of the "sensation" here was the 50mm 1.4 Art was optically wonderful but couldn't AF well enough on the 5DIII. Many reviewers praised it without mentioning the AF problems on Canon bodies, but I tried it and had unreliable AF. I sent mine back and occasionally wondered, a few years later, if it would have been any better on the 5DIV.

On the other hand, I had a Sigma 35mm 1.4 Art that did work fine on the 5DIII and even a little better on the 5DIV.

Sure would be great to hear from owners of any R body who use the Sigma 50mm 1.4 Art how well it AF's now.


I'm New Here
Oct 5, 2020
I've always found the Sigma Art 50 to be a good performer for autofocus, however I am aware that my experiences of AF often differ from what is commonly reported so I suspect my usage patterns are idiosyncratic.

Anecdotally I'd say the 85 1.2 II is the most reliable I've used for DSLR through-the-viewfinder autofocus as long as the subject is not moving at any speed, and that my overall gold standard for autofocus is the 85/1.8. But the Sigma 50 Art is not in my experience a long way behind. I have plenty of examples of action (eg kids on bikes or running around) shot at 1.4.

Lenses that make me anxious in some situations because they are prone to random autofocus misses include the old Sigma 30/1.4 EX, the EF 50/1.8, and (this one is controversial) the 135L. But the Sigma 50 Art I've never had a problem with.


CR Pro
Jan 25, 2017
I have an R5 with Sigma 35 mm 1.4 Art and Sigma 20mm 1.4 Art.. both nice lenses and I used them heavily for low light band photography with my 80D and got good results, sadly Covid put a halt to live shows for now. But they work well with the R5.

I also have the RF 24-70 2.8IS.. great lens.

I definitely can get better shutter speeds/lower ISO with the primes and it does make a difference and prefer to use them, but do lose out with the IS, RF Glass and depth of field.

However you gain much more light gathering with the higher aperture lenses which helps in correct exposure. Correct exposure is important as you go lower and lower in light vs lifting shadows which tend to be lacking detail once you're in very low light situations. The depth of field is definitely a consideration, but keep in mind with wide angle lenses (like my sigma 20mm 1.4 ART) the depth of field increases rapidly with a bit of distance. 1.2 will give more light but you'll need to be more careful where you focus.

Sample via Sigma 20mm 1.4 Art... Shutter 1/60th, aperture 2.8 and ISO 6400 vs Shutter 1/60th, aperture 1.4 and ISO 2500, probably could reduce the noise better but On1 has poor noise control compared to some other products. Otherwise its a decent product. Very similar results, but I can push the 1.4 a bit more (though how much more is a bit limited)
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Mt Spokane Photography

I post too Much on Here!!
CR Pro
Mar 25, 2011
I opened the door late one night to snap a photo of the snow with my R5 and 100mm L. It was only lit by a 60 watt equiv led porch light about 15 ft away. It was tinted yellow so I corrected the white balance and raised the exposure. ISO's were from 16000 to 51200 for the different shots I took. After some editing to reduce obvious effects from the noise, they were usable for a web site posting or printing at a reasonable size. At 1:1, the detail was missing.

A 3 stop faster lens would still be too slow but since it was a still scene, I could have used a long exposure with a little more care. I think a f/1.2 lens would have been fantastic but the subject was not worth it. I was mostly interested as to how the camera handled noise in low light and how much color correction was needed.

This one was f/3.2, 1/125 sec, ISO 32000. Its a jpg exported to a smaller size and then the forum reduces it even more.



Pixel Peeper
Jan 31, 2020
As someone who owns all of the RF lenses (except the 35mm F1.8), I'd say the F1.2 lenses are well worth the investment, especially for night time photography. For taking portraits, F1.2 may not be usable at all times, but it's good to have it when conditions require. With that said, I just wish Canon's going to release a 24mm/35mm F1.2 soon.
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