Mirrorless compatibility with Sigma 20MM F1.4 DG HSM | A

[justadude]

I’ve read random comments about compatibility concerns with some Sigma lenses and Canon mirrorless cameras in various places on the forums.  Most of those have been fairly specific for individual lenses and bodies, so that doesn’t help me so far.

I have an opportunity to buy a gently used Sigma 20mm F/1.4 Art DG HSM lens with an EF mount for 2/3 of the new price.  I do have a Canon EF/RF adapter, and would be using the lens on the R6 Mark ll, R8 and RP for night skies (mostly) and landscape work.  I like my Rokinon 14mm for night skies, but it’s too wide for some landscape, so I basically want to switch up to a 20mm lens - which would be good for both. 

Has anyone heard of these Sigma lenses not playing nice with the R-series bodies?  No need to tell me about some of the advance focus features with the R-series bodies not fully working with the third party lens, I am aware of that.  I’m just asking if you know of any known issues/concerns.  

[shadowsports]

Both of you made excellent points.  The Sigma EF 20 was released in 2015.  Its last FW update was in 2018.  A Sigma Dock is worth while, especially if you own more than one of Sigma's Global Vision lenses (Art, Contemporary or Sport).

[ebiggs1]

The bottom line is "fully compatible" but will they work? And I think that is a reasonably correct answer is, yes, they work. Probably better than your Rokinon which is not "fully compatible" either.

[justadude]

Correct on the Rokinon, EB.  Manual focus (which I love) but I have to set the camera to shoot with no lens for it to work - no big deal, I have to do that with all of the film era lenses I use on the mirrorless bodies.  

What I'm really looking at is that although the Rokinon is a nice astro lens, it is a little wider than I like for landscapes, and it has a lot of coma on night skies.  So I'd just like something a little narrower, and a little better quality... without spending as much as the RF 15-35mm costs.

[RRotunno]

If you’re still shopping, the Sigma Art 28mm F/1.4 is a great performer for nightscape work. I prefer the longer focal length for nightscapes because I like the milkyway a bit larger in the frame. Though with my R5 I don’t go longer than 10 second subs unless I’m using a tracking mount. I generally shoot it at F/2.8.