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.  

[Waddizzle]

Many older Canon lenses were released prior to the release of Dusl Pixel SF image senor cameras in 2009. Most of these lenses are NOT fully compatible with all the advanced features that are available with DPAF sensors. 

The shortcomings are most acute when shooting videos.  Nearly all third party EF lenses fall into this category.  Many were not fully compatible with DPAF sensors in DSLRs.

My best advice is stick to Canon EF mount lenses. But I don’t recommend investing much money in them.

The Canon RF lenses are your best option. 

[justadude]

Plenty of good information here, and thank you!  However, as I mentioned, this lens would be for night sky images, and landscape.  I knew a lot of the newer features would not work, and since it is for these subjects, I would not be using it for video (actually, I don't even like shooting video - but I know others reading this might appreciate that advice).  I just wanted to make sure I could shoot stills.  Not even concerned with frame rate because that doesn't come into play with these two types of photography.  

I agree fully on your suggestion on RF lenses being the best option.  However I don't see any fast (f/2.8 or faster) 20mm lenses in my current budget range.  That's why a $899 Sigma 20mm F/1.4 sounds tempting, and even better at the $625 used price.  If you can think of better 20mm Canon options in that price range, I would love to hear any suggestions you may have!

[March411]

Canon's current offering is limited to the RF24mm F1.8 MACRO IS STM @ $600 but it is not exactly what you are looking for but in stock. They also have one in their refurbish for $480 if you want to compromise a bit on focal length.

https://www.usa.canon.com/shop/lenses/refurbished-lenses?facet_lens_mount_type=1115

[justadude]

I have looked at that one, but it's not exactly a great astro lens for night skies, which is my first priority.  Also it's a bit redundant with my 24-105 (even though it's faster).  I've tried a friend's 18mm and 20mm and they just hit that sweet spot for a lot of the landscape work I do, as well as the night skies.  I know the 4mm (or 6mm) doesn't seem like a lot, but it kind of is to me.

I have a Samyang 18-28 F/4.5 film era Pentax mount lens which works great on the R6m2 during the day... but it's not fast enough for night skies, and it's horrible for infrared when I put it on the R8.  So I really just want a dedicated fast 20mm lens that works on all three mirrorless bodies.

[March411]

I get it, you know what you want which I completely understand. I didn't know if you knew they were available so I just wanted to throw it out there for you.

Personally I like all the Sigma glass I own and they perform great on my R bodies with the Canon adapter. Adding the 20mm to your stable of lenses in my opinion would only be a win.

[justadude]

"I didn't know if you knew they were available so I just wanted to throw it out there for you."

I appreciate you letting me know - as well as anyone else reading this thread that might be interested.  I am one of those guys with a touch of OCD who overthinks and over-researches things like this before making a purchase.  My wife is just as bad.  🙂

[March411]

I own several Sigma lenses as well as EF and RF mounts. All of the sigma lenses firmware has been brought to the latest version and every one of them perform flawlessly. I did have challenges with my 60-600mm, focus racking until I updated the firmware.

I can offer this information which was conveyed to me directly from Canon support. While they cannot support repairs they are extremely helpful with advice and information.

They conveyed that the Sigma EF mount lenses that the firmware can be updated through the Sigma dock will/should work the same as the most recent Canon EF lenses. Older lenses they suggested not to purchase.

Overall they recommended purchasing lenses that were not dated, to focus on the period where the R system bodies were released to the public. It is my understand that both Sigma and Tamron released firmware to allow their lenses to be used on R bodies. Seeing that you can still purchase the Sigma 20mm F/1.4 Art DG HSM it appears this would fit the criteria.

Do you have a place close by that you can bring you body and test the lens, maybe rent to ease your mind.  

[Waddizzle]

I agree. Sigma lenses are probably fine for shooting stills. They’re good video, too, provided you’re not pushing the envelope.

When it comes to shooting stills, not every lens is capable of the highest frame rates. 

[justadude]

"Do you have a place close by that you can bring you body and test the lens"

My first thought was to bring a couple of my R bodies in to one of the two local camera shops to test the lens, but neither of them have the 20mm in stock at the moment.

Thanks for the firmware suggestion!