These are great lenses and by all accounts offer fantastic performance at quite a reasonable price point. Everything below this sentence is purely personal preference.
Since these lenses (Sigma 20mm f/1.4 DG DN Art and Sigma 24mm f/1.4 DG DN Art) are so close in focal length and spec most of what is stated below will address both.
I will be the first to admit it. I do not fully get the lenses that many companies are releasing nowadays. I mean I get why a company releases new lenses. They like money. Getting ours specifically. They are businesses after all.
Wondering what the thinking is when companies produce prime lenses with only a 4mm difference in focal length. Not the first time I have wondered about this. I was similarly baffled by the Tamron FE 20mm and 24mm f/2.8 lenses. I doubt many would buy both. Seems one or the other would have done just fine. Also wondered why they would not just split the middle and go with a 22mm lens for instance. That would have been a very Pentax move.
Task at hand:
I have nothing against SIGMA. As confirmed by previous Foveon ramblings I hold them in very high regard.
I have nothing against Art lenses. An Art lens is currently one of my favorite lenses ever.
I have nothing against any lens companies currently releasing lenses.
But many lenses nowadays are released with specs that are well represented already. Some companies, like Rokinon/Samyang, are releasing upgrades to already solid performers. Let me qualify. For Sony FE mount lenses. Currently, other lens mount options are very thin by comparison. Largely owing to Canon and Nikon not playing well with others with their AF specs as I understand things. I get that too. They want that sweet, sweet lens profit to themselves. But I could get along with just about any camera on the market now so quantity, quality, and value lens options decide the camera mount for me. The L mount has multiple lens manufacturers, as a product of the alliance, but native manufacturer lenses are often varying degrees of quite pricey, and true third party options are relatively slim. The far majority of my Sony FE lenses are third-party and at one point I owned no Sony lenses. Currently I have just two. That is not because the Sony offerings are not good. They are excellent in fact. But it has more to do with the embarrassing riches of excellent third-party offerings at a lower price point. This alone justifies my staying with the Sony mount even as Canon and Nikon step up their mirrorless camera body game. I am brand agnostic, but I find it impossible to ignore the fact that for the price of a couple of the high-end native manufacturer lenses for other mounts I can build a whole third-party lens system. And I did. When I went to NYC last year I did not have a single Sony lens on me and did not feel lacking in any way because of it.
If I had an L mount alliance camera body I would be turning cartwheels right now. And rightfully so. This brings an excellent performing and solid value option to them. But in Sony FE land? The field is thick with options.
And right here is a good example of what I am on about. That Rokinon/Samyang AF 24mm F1.8 FE used for the two images above is also a solid performer and an even greater value. And unlike its earlier Rokinon/Samyang offerings build quality has taken a step in the right direction. Not to SIGMA Art levels, but quite good just the same. While we are at it I would put the IQ of that Rokinon/Samyang offering up against any lens. Yes, the aperture is slower, but I can counter with its smaller size and lower price point. Also brings an infinity focus on-demand feature that is great for astrophotography.
And that is just the start.
This lens has a lot of great competition already. But if you are adamant that the lens needs to go to 11… I mean f/1.4 there is the excellent Sony 24mm f/1.4 touted by many to be the best lens around at this spec regardless of the mount. Many say. Have never used one, but have no reason to doubt them given my experience with its sibling lens. And while the SIGMA is less expensive I am not sure I would be looking to save a few hundred dollars if I was looking for the next of the best. And I have already seen it mentioned that the Sony is sharper in the center wide open. If f/1.8 is on the table you have a few more choices. If you can tolerate even higher ISOs and less subject isolation there are plenty of affordable and very compact f/2.8 options and one f/2.0 from SIGMA themselves. SIGMA overall is one of its own biggest competitors at this focal length with four lenses at 24mm.
The 20mm stands alone as the only purpose-built for mirrorless f/1.4 lens at this focal length. The only other f/1.4 is SIGMA’s own adapted DSLR lens, but at the same price, being much larger, and possessing older tech the new model is a no-brainer. But if you are able to suffer an f/1.8 aperture Sony offers a more compact option at the very same price point.
But none of the lenses above is the main competitor for me personally. The same lens that knocks either of these lenses out of consideration was also behind me selling the Rokinon/Samyang 24mm f/1.8 above. It is also the reason why I never considered the Tamron 20mm and 24mm lenses mentioned above.
The Tamron 17-28mm f/2.8 Di III RXD.
You may be asking, “But the aperture…”. This is where personal preference kicks in. I do not do astrophotography so a faster than f/2.8 aperture was not a huge selling point for me. In fact, the 17-28mm does not exactly embarrass itself in low-light situations either.
That picture was taken on the same NYC trip as the Rokinon/Samyang 24mm f/1.8 pics above. And you know what? There was no reason for me to bring both of these lenses. The Tamron would have done just fine.
Do you know what is a huge selling point though? A lens that adds the flexibility of covering 17-28mm while being smaller and lighter at the same price point when compared to the new SIGMA lenses. The Tamron does sacrifice any manner of on-lens body controls like switches and hold buttons, but I am fine with that as well.
It has swift and reliable autofocus.
While not a stellar aperture spec subject isolation is available at close distances.
It has great colors.
Has a strong IQ performance across the frame.
So a great lens. Works for me as an alternative largely because these are focal lengths I do not use as often as others. Enough of that. Not everyone’s cup of tea. Understandable. For those who live at wide focal lengths, higher-end options with faster options would make sense.
Like I said in the open these lenses themselves are not what baffles me a bit. What does baffle me a bit is that so many companies keep producing the same lens spec with their names on it. Like when I wrote a post about the Sigma 24-70mm f/2.8 DG DN Art and Tamron 28-75mm f/2.8 Di III VXD G2. I did not bother with a real comparison because either lens would suit me just fine. As would the SIGMA Contemporary 28-70mm f/2.8. (I noticed folks that used to bellyache about the Tamron 28-75mm f/2.8 “only” going to 28mm do not seem the least bit bothered that this lens covers an even narrower focal range at 28-70mm. Funny that. Either would do for me.) As would the Sony 24-70mm f/2.8 GM II. As would the Rokinon/Samyang 24-70mm f/2.8 (Warning: Seems there are build issues according to B&H reviews.). Five f/2.8 purpose-built for mirrorless lenses in the same range to choose from where most systems have one or two native mount-only options at best. If you are willing to relax your aperture spec requirements many more lenses (11 currently) in this focal range are available.
And it seems like this lens spec repeat release trend is showing itself across other specs as well. Rokinon/Samyang recently released two new lenses that are identical spec replacements for their 50mm and 85mm f/1.4 lenses that they already have on the market. This is all great if you just like a certain lens brand, but if that does not matter there are now an amazing number of lenses available at nearly every spec.
So what do I want? Nothing really. I continue to mark myself safe lens release after lens release since I have either tried a lens like it or have that spec covered already.
But if these lens companies want to part me from my money they need to start thinking outside the box. And some are.
Rokinon/Samyang zigged a bit with their 75mm f/1.8 compact and wonderfully performing lens.
It gave an excellent portrait performance in a package similar in size and weight to a 50mm prime. It was especially appreciated during a Harlem stranger portrait session during a NYC photo walk last year. It was only sold on when I found it was soon put away for the flexibility of the Tamron 28-75mm f/2.8 before the day was done. There is a pattern here.
Rokinon/Samyang was also on to something when they released the AF built for FE mount 135mm f/1.8. If I was not already enamored with a nonsensical solution already…
…this lens would have been a definite threat to my checkbook. A lower-priced alternative to a great Sony lens at a classic portrait length is a great idea.
But what would really be great would be for more lens companies to swing for the trees like Tamron did with their fantastic and ridiculously flexible 35-150mm f/2-2.8.
A lens so unique that it had me replacing two perfectly good zoom lenses (Tamron 28-75mm f/2.8…
…and 70-180mm f/2.8)…
…I already had and a couple of primes (Like the Rokinon/Samyang 35mm f/1.8.)…
…while I was at it… Wait? Really great? What? Wait a minute.
On second thought don’t do that. Keep making the same spec lenses. I was fortunate that this new 35-150mm lens replaced so many lenses that gear trades saved the day. It kind of made some sense by cutting down on the lenses owned/carried. But more continued innovations like that might crater everyone’s finances.
Now, all that being said I will end this post as I started it.
These are great lenses and by all accounts offer fantastic performance at quite a reasonable price point. Additionally, if you are a part of the L mount alliance this is a momentous occasion. You have now been provided with two fantastic options with superior aperture specs to what you currently have available and at a fraction of the price of a slower aperture, narrower focal length Leica lens. Good times.