Leica SL2-S Long-Term Review: The Incredible Workhorse That Produces Stunning Images Even in Low Light

With the new Leica SL3 about to start shipping, where does that leave those of us working with previous generation SL models? With its jumbo pixels and stunning low light performance, my Leica SL2-S is definitely going to be a hard act to follow.

Introduction

As I write this article, it’s been a little over 3 years since the 24 MP Leica SL2-S was first released as an alternative to the earlier 47 MP SL2 in Leica’s L-Mount range of full frame mirrorless cameras. For anyone willing to forego the higher resolution of the SL2 in favor of much better low light performance, the SL2-S was (and still is) a great option for photographers looking for a camera that can handle more challenging lighting conditions. The promise of being able to capture great images even in very low light is actually what drew me to the SL2-S in the first place.

With all of their complex electronics for image capture and processing, digital camera bodies are essentially computers that you can mount lenses on. And while the passage of three years might not see great strides in the evolution of lenses and optics, it is certainly long enough to see some major upgrades to the sensor and chip technologies that are the beating heart of modern digital cameras. In fact, almost fifty years after he first coined his eponymous law predicting the exponential rise of the price-performance ratio for silicon chips, the late Gordon Moore is still pretty much right on the money, even in 2024.

Beyond any new features then, that may or may not be factors in your decision to upgrade to the Leica SL3, this latest iteration in the SL line is sure to showcase the kind of imaging performance improvements that will likely be determinative for most Leica SL users contemplating an upgrade. This is something we have come to expect with each new camera generation. If there’s any one hook that clinches the SL3 upgrade deal, it will almost certainly be the allure of its new 60 MP sensor and Maestro IV image processor.

So, as a user of the Leica SL2-S for the past couple of years, where does this leave me?

This article is not going to be a direct comparison of any of the previous SL cameras with the new SL3 — especially since, like most of us, I have yet to get my hands on an SL3 or even see one in the flesh. Nor is it going to be a detailed, technical review of the SL2-S and its features and specifications. The SL2-S has already been around long enough for there to be a wealth of technical reviews of this camera available online for anybody looking for this information.

In the hope that this article will be helpful for anybody who is thinking of using a Leica SL2-S or SL3 in their own photography, I would like to share my experience of the last couple of years in which the SL2-S has been a mainstay for me, both in my professional work and for some of my personal photo projects. I will discuss one or two technical aspects of the SL2-S in the context of my decision to upgrade (or not) to the Leica SL3, but for the most part, this article will be a personal account of what it’s been like for me to shoot with the SL2-S these last two years.

Before we get too far into my review, in the interests of full disclosure, I want to make it clear that I purchased my Leica SL2-S with my own money and that my opinions about this camera are entirely my own. Nobody loaned me any of the gear that I’m writing about and this is not in any way a sponsored review.

Love At First Click

There’s a lot to love about the Leica SL2-S. It’s an absolutely beautiful camera that feels great in the hands — like a craftsman’s tool that makes you aspire to create the kind of images that are worthy of it. As I’m writing this last sentence, I can already imagine some of the people reading it, starting to froth at the mouth as they leap to their long-suffering keyboards to hammer out angry rebuttals — "it just takes pictures like any other camera; there are cheaper cameras with better (name your feature of choice); gear doesn’t matter; etc."

At the risk of alienating a slice of my audience, I’m going to say that I think that gear does matter (at least to me).

I love that the SL2-S just gets out of your way when you’re shooting, allowing you to focus on your photography unencumbered by the cognitive overhead of having to “operate” your camera. I’m not a fan of cameras that have a lot of their key features buried in complex, nested menus. The SL2-S feels intuitive and comfortable, and it’s a joy to use thanks to some of the best ergonomics that I’ve ever encountered in a camera.

This is a big deal for me.

It allows me to keep my head in the zone while I’m shooting — entirely focused on capturing what’s in front of me and able to work without constantly interrupting my flow to dive into some setting on my camera. I once heard a master carpenter say that better tools were worth the extra money because the superior experience of working with them gave him a closer connection to his craft. Now I was never any good at woodwork when I was in school, but I can totally relate to this perspective in the context of cameras and photography. 

We should also talk about the ruggedness of the SL2-S. I’m somebody who takes great care of my cameras, but I definitely don’t coddle them. In search of great photographs, I have schlepped my SL2-S across sandy, windswept beaches, through the dirt and dust of New England’s fields and farmyards, and the snow and rain of its incredible landscapes — all without ever encountering a problem due to the ingress of dust or moisture. The IP54-rated weather sealing on this camera is an absolute boon for anybody who wants to get out and photograph the real world in its often less-than-ideal conditions. And although I’m certainly not in any hurry to test it, you also get the sense that the hefty, all-metal body of the SL2-S could probably take a beating if necessary (or even stop a marauding grizzly bear in its tracks if you threw it at him hard enough!)

A Versatile Workhorse

At the end of the day, none of these wonderful, aesthetic, intuitive, or rugged qualities of the SL2-S would mean jack if it wasn’t also a dependable camera capable of producing great images - which I’m happy to say is the case on both counts.

The output of the SL2-S is, in a word, fantastic. In combination with some of the excellent L-Mount lenses that I have used it with, its 24 MP sensor produces absolutely superb images. This is hardly big news. Everybody knows that Leica cameras and optics are renowned for their image quality, and the SL2-S certainly lives up to these expectations. The L-Mount lenses that I have used the most over the last couple of years are the Leica Vario-Elmarit-SL 24-70mm f/2.8, the Panasonic Lumix S 85mm f/1.8, and the Sigma 20mm f/1.4 DG DN Art Lens, and I have found all of them to be capable of yielding stellar images in combination with the SL2-S.

In terms of the sensor resolution, I feel that 24 MP is kind of a sweet spot for a camera. I have never encountered a problem related to the lower resolution of the SL2-S, that made me regret not going with the SL2 instead, with its 47 MP sensor. On my Leica Q3 with its fixed focal length 28mm lens, I do find the extra resolution of the 60 MP sensor useful, since it allows me to crop down to the equivalent field of view for longer focal length lenses. On the SL2-S, however, I can just use the focal length lens that I need for the shot, and so this is less of an issue. You could make the argument that more pixels are always useful/better, but the downside of cramming more pixels on a sensor is that the pixels get smaller and therefore, innately noisier. It will be interesting to see how the SL3 with its higher resolution 60 MP sensor, handles low light conditions. There is no doubt that the new sensor and Maestro IV image processor in the SL3 will leverage their next-generation circuitry to handle noise even more effectively, and this will be essential if the SL3 is going to be able to squeeze more signal and less noise from its smaller pixels and match (or even exceed) the low light performance of the SL2-S.

We shall see.

I have found that the nimble and intuitive ergonomics of the SL2-S make it a great camera for shooting weddings and events. Less futzing to change the camera settings means that you can respond more quickly to the events unfolding in front of you, or to changes in the lighting conditions. This reduces the likelihood that you fluff the shot because you weren’t ready, or even miss the moment entirely because you were buried in some camera menu.

But where the SL2-S really shines is in low light conditions.

This is such an important benefit of the SL2-S that I will devote the following section of this article to it. In the context of weddings and events, when night falls and the lights go down for the reception or event that you’re shooting, it’s hard to overstate how reassuring it is to have a camera that can handle those kinds of challenging light conditions with such ease — producing beautiful, useable images right out of the camera, even at high ISO settings.

A Maestro in Low Light

The upside of the lower 24 MP resolution of the SL2-S compared to the 47 MP of the SL2, or the 60 MP of the SL3, is that with fewer pixels on the full frame sensor, the pixels themselves can be larger. This can be a great advantage when it comes to image quality. Bigger pixels produce less noise and have a wider dynamic range than smaller pixels. In terms of image quality then, while sacrificing somewhat on the resolution side of the equation, the SL2-S benefits with regard to wider dynamic range, and lower noise.

In the images below I show a photograph I took with the SL2-S, of a performer in a very dark and crowded bar. This scene was captured at ISO 10,000 and the right hand (before) side shows the image straight out of the camera after basic processing with Adobe Lightroom, but with absolutely no noise reduction applied — either with the traditional noise reduction slider, or using Lightroom’s newer AI noise reduction feature. The left hand (after) side image shows the result of applying Lightroom’s AI noise reduction. As you can see, the image straight out of the camera is already very good, and shows remarkably little noise given the high gain on the sensor.

At 24 MP on the full frame sensor, the pixel size of the SL2-S is 5.94 µm on each edge, compared to the new SL3’s 3.79 µm pixels. This translates into almost a 2.5x advantage in the light-gathering area of the larger SL2-S pixels. You can see this illustrated in the diagram below which shows a comparison of the relative areas of the individual pixels from the SL2-S (blue) and the SL3 (orange).

This means that Leica will undoubtedly be counting on the electronic wizardry of their next-generation sensor and image processor on the SL3 to counter the tendency of its smaller pixels to yield more noise and a lower dynamic range. Given the rapid evolution of sensors and image processing chips, we have already seen the megapixel count on camera sensors advance ever higher, often paradoxically, accompanied by improvements in image quality as a result of advances in the electronics. When it comes to higher resolution sensors and better image quality therefore, it’s hard to see this have-your-cake-and-eat-it-too trend coming to an end anytime soon.

Flash: The Achilles Heel of the SL2-S (and SL3?)

Lest I should end this review leaving you with the impression that everything is all puppies and rainbows when it comes to the Leica SL2-S, there is one aspect of this camera that I do find frustrating, and it’s quite a biggie.

There are often situations in which you want to use flash at shutter speeds higher than the native flash sync speed of your camera — using fill flash outdoors in bright sunlight for example, or for action photography. In these scenarios, a typical solution is to use a strobe capable of High Speed Sync (HSS), to avoid the problem of catching the shadow of the shutter in your image as the shutter crosses the frame.

The Leica SL2-S has a maximum flash sync speed of 1/250 of a second which is pretty respectable for a modern camera with a focal plane shutter, but when you use it at higher shutter speeds, hooked up to a strobe that can support HSS, the results are surprising and frankly, rather disappointing.

Both of the images below were captured at 1/800th of a second to demonstrate the use of HSS (our little pooch Rufus kindly modeled for me). In the right-hand image, I set up my Godox V1 for HSS on my Panasonic S5IIx (which also natively syncs flash up to 1/250th of a second). At a shutter speed of 1/800, the HSS worked perfectly - no shutter shadow in the frame at all, despite the high shutter speed. In the left-hand image captured with the SL2-S under identical conditions and with the exact same strobe, you can see that the HSS failed miserably and most of the frame has been darkened by the shadow of the traveling focal plane shutter.

So what gives?

I had the exact same experience testing the SL2-S with the Westcott FJ400 Strobe, after which I did a little digging around online to see if I could figure out why the SL2-S does not play nice with HSS strobes. As of the writing of this article, the only relevant information I could find was some speculation that the Leica SL cameras only support HSS with Leica’s own proprietary flashes, but I have not been able to confirm or test this, so it’s definitely information to take with a big grain of salt.

I don’t know if this issue is something that Leica could fix with a firmware update, but it’s a disappointing strike against what is otherwise a really stellar camera. The postscript to this HSS experience was that I ended up purchasing a Panasonic S5IIx for this kind of flash photography, since it leverages my already significant investment in L-Mount lenses. The S5IIx also happens to be less than half of the price of an SL2-S and a fantastic camera for video to boot!

Sadly then, despite all of my enthusiasm for the SL2-S, I would have to say that if you are planning on working a lot with strobes, then the SL2-S is probably not the camera for you.

The big question is — will the new Leica SL3 be similarly hobbled when it comes to the use of flash?

Watch this space.

Conclusion

Despite the whole HSS thing, I still love my SL2-S, and were it not for that issue, I would have little to complain about it. With regard to upgrading to the SL3, I’m definitely not in any hurry to do so. I will be very curious to see whether its new sensor and Maestro IV image processor will be able to equal or exceed the low light performance of the SL2-S. When it comes to flash though, I don’t believe that Leica currently offers anything close to the Westcott FJ400 in output, so if the SL3 has the same HSS issue as the SL2-S, this would be a deal breaker for me.

Perhaps if anybody from Leica is reading this article, they could provide some clarity on this problem, and perhaps even flag it as an issue with their development team for a possible fix (if this is feasible) in the next firmware update.