Sony has dominated the full-frame mirrorless interchangeable-lens camera space with its A7 series since it launched two years ago -- not terribly hard, as Sony's had the only cameras in that space until now. Enter the Leica SL, a powerful pro-oriented model with a few drawbacks.
As is pretty typical for a Leica, the camera costs roughly twice as much as its nearest competitor, the, at $7,450 for the body (£5,050 in the UK) and $4,050 for the first available lens (£3,150), the Leica Vario-Elmarit-SL 24-90mm f2.8-4. (No prices for Australia have been announced yet, but the US body price converts to AU$10,280, while the lens works out to AU$5,590.) The price looks a lot less steep if you compare it to full-frame dSLR models with fast continuous shooting, however.
The sensor and processor are the same as the, so you'd expect the photos to look similar. The SL's photos and videos are generally terrific in all but very low light. If you want your out-of-the-camera JPEGs to look great you need to tweak the default settings because they'll clip a little too much shadow and highlight detail, or alternatively you need to under/over exposure high- (bright) and low-key (dark) scenes. You probably want to underexpose high contrast scenes as well, because it's relatively easy to recover shadow detail but not as much for the highlight detail. That's pretty typical, though.
Leica's aesthetic for low-light photos is to preserve detail at the expense of noise; in other words, low-light JPEG shots look a lot grainier than those of other cameras, but they also don't get get that over-smoothed look. If you don't like it, though, you can increase the in-camera noise reduction.
Leica's DNG raw files preserve color better (naturally) and stand up to software noise reduction very well through about ISO 12500. Beyond that the images are usable, depending upon the scene. You don't gain much in the way of detail by processing the raw at high ISO sensitivities, though.
The color balance is neutral and accurate in both our raw and JPEG test shots, but in actual daylight the skies in some photos -- it looks like it happens in very bright shots -- get pushed to cyan. I haven't seen skies like that come out of a real camera in years. They look perfect in the raw photos, though.
I suspect Leica is performing more moire reduction in the JPEGs than it did in the Leica Q, and even the DNGs are improved in that respect (though the very different lenses could account for it as well). The JPEGs are just a little softer than the DNGs, and the DNGs have significantly more moire, though I couldn't spot any in my photos from field testing, just the portion of our test scene designed to show it. I think a sharper lens (as the 50mm f1.4 will probably be) might resolve a little more, though, resulting in more moire.
The camera's video 4K looks really good as well. Once again, you should decrease the contrast if you're shooting in bright conditions and want good out-of-the-camera footage, since it clips the highlights and shadows as with the stills. The one built-in profile it has, Leica V-Log L, is one of the flattest profiles I've ever seen, and the camera needs a "preview" feature similar to thefor working with it. However, it preserves the highlights as expected for grading.
I did not test recording via HDMI, however, which supports 4:2:2 10-bit. Internally, it's the typical 4:2:0 8-bit. It's possible that the higher bit rate workflow will do a somewhat better job preserving highlight detail. However, the very low-light video wasn't nearly as good, in part because it seems to use the same noise-reduction settings as the stills, so there's quite a bit of noise jitter. The A7S II definitely outperforms the Leica SL in that respect. When shooting in HD, the SL uses the entire sensor.
While it will be getting an electronic shutter in a forthcoming firmware upgrade, the focal-plane shutter unsurprisingly produces slanted verticals in fast-moving subjects (like a train).
Overall, the Leica SL performs quite well; it's certainly faster than the Sony A7R II and even theunder some conditions. It is very slow to power on, focus and shoot at 1.9 seconds, though that's typical for mirrorless ILCs.
Time to focus and shoot in good light is excellent at 0.2 second and 0.3 second in dim; however in situations darker than our test scene (roughly equivalent to a dim living room) I found its contrast autofocus system hunted quite a bit. Two sequential shots took 0.4 second, for raw or JPEG, also quite good.
The Leica SL certainly has the fasted rated continuous-shooting speed in its class: 11fps (high) without continuous autofocus or autoexposure and 7fps (medium) with both. I only got it up to 5.8fps in the latter mode with our standard test procedures, but acheived 7fps for JPEGs with a shutter speed of greater than 1/500 second. I couldn't get the raw burst past 5.8fps, though. It can sustain the raw burst for a few more than 30 shots, but for an essentially unlimited number in JPEG (I stopped checking at 60). I might have been able to sustain a faster rate for the raw had the camera recognized my fastest 280MB/sec. card, the SanDisk 64GB Extreme Pro U3 model. Leica says it should work with U3 cards.
While it doesn't support AF/AE at 11fps, that may not matter for some jobs. With sufficient depth-of-field (and depending upon the action your're shooting), 11fps is fast enough that the subject remains in focus for a chunk of it -- the contrast autofocus areas are fairly large, which can be a blessing and a curse. The 37-area setting is a diamond-shaped array, and 49-area just fills in the holes in the corners to form a rectangle. At the 7fps speed it had a pretty good focus-hit rate.
For speed shooting, keep in mind that it lacks tracking autofocus, and that its zone AF frequently picks the wrong part of the zone for focusing. Just like everyone else's.
Like the camera, the battery is big -- it's the same capacity as a typical dSLR battery, but because it has to power a lot more displays it's rated at a lower life of about 400 shots. It still blows past the life of a typical Sony A7 series camera, and seemed to last a lot longer than its rating in practice.