This was the third of the Sigma ART series primes that I purchased (I also have the 35mm f1.4 ART and the 50mm f1.4 ART) and it doesn’t disappoint! A little quirkier and harder to get the most from than the other ART lenses I own, but it does produce awesome images. Once you get the hang of it.

First impressions of Sigma 20mm f1.4 ART

There are a few key points that you’ll need to get your head around before thinking about this lens.

Firstly, it’s pretty heavy. Not crazy heavy – a long telephoto will definitely tire your arms out way more. But for its size, it’s heavy. That’s because it has a lot of glass in it. You can tell as soon as you take it out of the box and you see that big dome of glass on the front.

Sigma 20mm f1.4 ART lens
This is the Sigma 20mm f1.4 ART – it’s quite a heavy lens, but not as heavy as a fast zoom, like the Canon 70-200mm for example.

That weight though also makes it feel high quality and well made. And it’s certainly that. Despite a reasonable price tag, great value in comparison to other premium lenses, it really is solid and dependable.

Once you’ve got the lens on the camera, it delivers everything you would expect from a Sigma ART lens – sharp, great in low light, wonderfully rich images with great range and contrast.

And that 20mm width, on a full frame sensor, is just amazing. So much fun to work with!

Sigma 20mm f1.4 ART - Budget Pro Photo REVIEW
That big domed glass on the front… it’s cumbersome, but it’s also SHINY. Very shiny!

Background to Sigma ART series

Back in 2013 Sigma announced that they were starting a whole new set up of lenses. They launched the Art lenses (A), the Contemporary lenses (C) and the Sport lenses (S).

The Art lenses were intended to be super sharp and super fast (low f-stop), allowing ultimate flexibility for those of us more concerned about look, and less about everyday use and focal length or speed.

The Contemporary lenses are supposed to be the jack-of-all-trades lenses. They are designed to be lightweight, easy to use, flexible and great for generalist every day work.

The Sport lenses are what you’d expect – rapid autofocus and long telephoto zooms, but at the expense of probably some weight and some sharpness.

Now, having said all that, they’re all really good at pretty much everything. All my Art lenses are used for daily work, but I know that if I stop down and get the camera on a tripod, I can achieve some truly breathtaking results.

Sigma – The Company

Sigma themselves are an interesting company (check out their website here). They are family run and independent and pride themselves on not wasting money on flying their flag to the whole world. Their website says “We don’t have Super Bowl commercials. And paid celebrities don’t endorse our products.” Which sums them up really. The money you spend on Sigma lenses goes towards good lenses. That’s it.

Sigma now have (as of January 2020) 29 lenses available on their website designated with the Art label. There is only one lens with a max aperture of f4, all the rest are f2.8 or faster. And what they’re really known for is their list of f1.4 lenses.

Sigma 20mm f1.4 ART - Budget Pro Photo REVIEW
See that? Not a lens cap like other lenses, that grips the filter threads. And that is because this lens doesn’t have filter threads, making it tricky to use filters. Which is a weakness…

The Sigma 20mm f1.4 ART – the numbers

The important stats on the Sigma 20mm 1.4 are as follows:

  • Focal Length: 20mm
  • Angle of view: 94.5° (35mm)
  • Max Aperture: f1.4
  • Min Aperture: f16
  • Diaphragm Blades: 9 (rounded)
  • Weight: 950g / 33.5oz

Translated, what those numbers mean is that this lens is super-wide on a 35mm sensor, super-fast with that max aperture of f1.4, gives lovely bokeh with its 9 rounded diaphragm blades, and is fairly heavy (more than 2lbs!).

It’s not as heavy as a long telephoto lens, of course, but for a prime 2lbs is pretty chunky. It’s worth me putting in here that I don’t find it all unwieldy. I think it’s a good balanced lens, and with it mounted on a Canon 5D4 with battery grip you’ve got a heavy unit, but it’s workable.

Sigma 20mm f1.4 ART - Budget Pro Photo REVIEW
A photo taken of my daughter on the Sigma 20mm f1.4 ART. This was part of a shoot with several strobes for some images to composite. As you can see, it’s tack sharp, and I like the view angle you get. It’s different!

The images

And so, to the really important bit… what are the photos like?

You know what, I just love the look of the Art lenses. My 35mm ART is literally the best lens I’ve ever had and it is the lens I use in almost all my commercial jobs.

The 20mm carries on that tradition. It gives you insanely sharp images with nice deep contrast and beautiful bokeh.

Sigma 20mm f1.4 ART - Budget Pro Photo REVIEW - family portraits
Look at that short depth of field! On a 20mm lens! You don’t see that every day.

There are some drawbacks, and as mentioned right at the top of the article this lens takes some getting used to. But I think it’s worth working with those weaknesses. After all, what lens, no matter the cost, doesn’t have some weakness or other.

So, let’s get to it…

The GOOD things about the Sigma 20mm f1.4 ART lens

  1. It’s super wide and you can focus pretty close to the lens, so using it in way other than intended (assuming it was really intended as a landscape lens) such as group shots, dynamic portraits etc., gets some awesome results
  2. That f1.4 really lets you photograph in almost any light.
  3. It’s well built and sturdy
  4. The photos it takes are insanely sharp (provided you make some allowances for the weaknesses, see below)
  5. It’s a great lens for creativity and coming at your photography from a slightly different angle
Sigma 20mm f1.4 ART - Budget Pro Photo REVIEW - night shot
What other lens do you have in your bag that let’s you take photos at night (or almost at night) handheld, with almost no noise?? That’s the amazing f1.4 aperture at work. It jusy hoovers up the available light!

The BAD things about the Sigma 20mm f1.4 ART lens

  1. It’s a little heavy
  2. Loses a bit of sharpness wide open at f1.4
  3. Serious vignetting at f1.4
  4. Can have focus problems out of the box which need to be corrected using the Sigma USB adapter (see below for my experiences)
  5. A certain amount of bowing, as you would expect with a 20mm lens
  6. No filter threads
  7. Huge domed front element, preventing most filter use
  8. That domed front element is prone to scratching
  9. Low maximum f-stop number

Bad points broken down

There are a few negative points there, but I can’t see one that is unique to this lens apart from maybe one. So let’s talk about that first.

I got my Sigma 20mm f1.4 ART brand new. When I excitedly unpacked it and started using it I found that the results I was getting weren’t great. Quite a few of my images, especially in a certain focal range, were a little soft.

I did some experimenting with auto and manual focus, trying to get to the bottom of what was going on. I found that the lens itself was not the problem. I was getting super sharp results when I focused manually (and got it right) so the lens was capable of sharp images.

Sigma 20mm f1.4 ART - Budget Pro Photo REVIEW - HDR landscape shot in San Diego
Just look at that field of view! Crazy!

Autofocus can have problems out of the box…

Therefore it had to be the autofocus. I knew already that my camera didn’t have any problems, because I had been using other lenses without any issues for years. We did a little research on the internet and found that the 20mm has some history of not quite being perfect straight out of the box.

There were a few stories of people who had sent theirs back because of this focusing issue. I also found other stories of people who had the same issue and fixed it themselves using Sigma’s USB Dock (on BH Photo Video here).

The Sigma USB Dock

So I decided that rather than send my lens back, I wanted to test this dock out. I have other Sigma lenses so it wouldn’t be a bad idea to have this dock, to update firmware and have ultimate control of my lenses.

Here’s the bottom line – the Sigma dock is super easy to use for updating firmware, it is NOT easy to use for tweaking focus issues. The reason for this is that in order to fine tune focusing properly, you really need to be scientific about it. You should really set up a range in your yard with marker sticks every few feet, then tweak and test, tweak and test.

I don’t quite have the patience, or the time, to do that. So I ended up looking closely at what my lens was doing, estimating focal lengths and doing some educated guesswork.

I think I’ve fixed the problem, I seem to be getting sharp images across the focal range, but without going through the scientific test process it’s hard to be sure!

Sigma 20mm f1.4 ART - Budget Pro Photo REVIEW - family photos
I’m totally happy with the focusing on this lens now, it is tack sharp throughout the focal range.

Other negative things – no filter thread (and low max f-stop)

If the 20mm ART lens was intended as a landscape lens, then the fact it’s pretty difficult to use filters with it is surely a problem?

Because the lens has that big domed front element and fixed hood, there’s no easy way to use filters. Most of your affordable filter systems rely on using filter threads on the front of the lens, and other systems use a matte box or attachment on the front to use square filters.

So that’s a negative point for me.

It’s also a double negative in combination with the relatively low max f-stop number. The highest the 20mm f1.4 will go is f16. For reference, my Canon 24-105 f4 L will take you all the way up to f22.

Am I being too picky??

I sound like I’m being as ass here… why would I go and buy a super fast f1.4 lens, and then moan that I can’t make it slow enough??

Well the answer to that is again, the landscape thing. If you’re mounted on a tripod and doing a long exposure, you can’t slow it down enough. Max aperture is f16 and no easy option for ND filters means this lens is kind of useless for any long exposures with any kind of light. You could get something out of it at night, but if the sun is anywhere near the horizon or above, and this lens won’t help you.

Sigma 20mm f1.4 ART - Budget Pro Photo REVIEW - low light performance
Low light performance is insane! But the lack of a filter thread is tricky in bright sunlight.

The good outweighs the bad!

Those are the only bad point to this lens. And now that I’ve fixed the focusing issue, my only real gripe is that you can’t use filters with it. And let’s face it, you probably can, I just haven’t come across an affordable system that works with this lens yet. I’m sure some of you will be screaming as you read this about this system or that system that I’m missing.

So then let’s turn to the positive stuff.

To cut a long story short, I love this lens. I use it quite a bit, it’s probably second most used lens for general work, behind the Canon 24-105. It’s maybe third for high end portrait work, behind the other two Sigma ART lenses in my bag, the 35mm and the 50mm.

It gets used, regularly, and I love the results. If you’re looking for a fast prime, wide angle lens, then this is a really great choice.

Sigma 20mm f1.4 ART - Budget Pro Photo REVIEW - close up work
The Sigma 20mm f1.4 is sich a great lens for family photos, when you can get really close to your subjects and have some fun!

Why the Sigma 20mm f1.4 ART is getting reviewed on BPP

Just thought I’d address this question quickly before we wrap up… this is not really a budget lens, but the Sigma range of lenses are priced way cheaper than the equivalent Canon or Nikon premium lenses. There are no budget options for a fast 20mm prime lens. Your choices are generally pretty darned expensive. So it is actually one of the cheapest in its class. I don’t own any of the super-premium Canon lenses. I own some L-series lenses, but only the lower end of the price range for L lenses.

If I want super high quality at reasonable (but not cheap) prices, then Sigma really is a great choice.


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