It hit us in September last year: the pre-production model of the new Leica SL3-S. And it made the earth shake a little - at least symbolically speaking. But everything in order:

A little over a year ago my friend Christian Habermeier and I tested a pre-production model of the Leica SL3 in Iceland. We were very impressed with the camera: handling, robustness, image quality – everything was top notch. The autofocus was also improved compared to the previous SL2 model, but there was still room for improvement with very fast subjects. Christian and I were - and are - so enthusiastic about the camera that we are now both taking our photos in the reportage area with the SL3. The autofocus has been further improved with firmware upgrades so that it leaves little to be desired for photography. But the AF bar is set higher for filming. And this is exactly where the SL3-S comes into play:

Except for the color of the Leica logo, the Leica SL3-S looks the same as the SL3. The entire operating concept is also identical. You can find out what makes the two cameras, which are practically identical on the outside, different from the inside in this article (press photo: Leica).

*The SL3-S impressed me in the field test (Photo: Marco Huber).*

Why two camera models from the same line?

All camera manufacturers release different models for different purposes. At Sony there are so many that, to be honest, I've lost track of them. Leica limits itself to two models, and that makes perfect sense: On the one hand, we have the SL3, which with 60 megapixels leaves little to be desired in terms of resolution, and the SL3-S with 24 megapixels, whose sensor produces slightly better results in high ISO due to the larger pixels -Area and is more suitable for filming. But if you want to film with a camera, it also needs powerful autofocus. And – let’s get this out of the way: Leica has done its homework here. More on that later.

Working with the SL3-S

At Leica, a lot of specialists are racking their brains about how to keep the operation of a camera as simple and individual as possible. This is difficult because cameras have more and more functions and are therefore becoming more complex. Simplicity of operation with more and more functions – this is diametrically opposed. But the people from Wetzlar do it really well: cleanly structured menu navigation, individually programmable screen display, video and photo menus strictly separated and now even color-coded, useful icons, etc. With three wheels and various buttons that I have assigned to my personal taste , I can tailor the camera 100% to my personal needs. The feel of the camera is a dream, the wheels don't wobble a bit, nothing is "flimsy", the viewfinder image is clear and sharp. The body is milled from a block of magnesium, and the camera is extremely well sealed against moisture and dust.

In October 2024, Leica gave us a look behind the scenes. The picture shows the production stages of the aluminum back shell for the Leica SL (first generation). The latest SL generation (SL3 and SL3-S) has a magnesium die-cast back shell. The advantages of magnesium are a significantly lower weight and the ability to cast more complex shapes. Leica is also continually developing its cameras in the material area.

Constancy

When I receive a test camera, it naturally comes without instructions for use. So I have to find my way around myself. For some time now, Leica has been striving to make the user interface identical for all camera lines – Q, M and SL. The further development of this interface is carried out with great care and a sense of proportion, so that you can immediately find your way around when switching from one camera line to another or from an older to a newer model. Therefore I didn't need any warm-up time with the SL3-S. Camera: Turn it on and off you go.

Innovation

But a lot has changed inside the camera. The sensor still has 24 megapixels like the SL2-S, but it is a newer model. And – really the most striking and most important thing: the autofocus of the SL3-S performs massively better. It is now at the level I always wanted for a camera like this. Because I don't think much of laboratory tests, I asked Andrina Trachsel, former Swiss ultracycling champion, if I could accompany her in triathlon training with the SL3-S - it's hard to find a better and more attractive test option ;-).

*6.30 a.m.: Start of the training day. Andrina starts the warm-up, my assistant Chiara and I get the equipment ready (Photo: Marco Huber)*

Andrina in training

The day is just beginning to awaken, the temperatures are still rather cool and it is drizzling slightly. But Andrina is tough, the weather conditions are not a problem for her. For me it's good to know that the SL3-S is not inferior in this regard. The rainy atmosphere creates a very special ambience, and right at the beginning a photo is taken that is my favorite picture from the entire series:

*Leica SL3-S, 1/80 sec., f 2, 250 ISO, Apo-Summicron SL 2.0/35 mm. Image editing in Lightroom*
I held the camera just above the surface of the water, which is possible because the Q and SL cameras also have a foldable screen. The APO-Summicron SL 2.0/35mm draws brilliantly, and the difference between the zone inside and outside the focus area is striking. It should be mentioned in passing: Despite their compactness, the 2.0 APO fixed focal lengths are incredible powerhouses. Of course they are not as small as the M lenses, but that is due to the fact that they are autofocus lenses.

Mounting an SL lens from the APO prime series (it's the 75). Good to see how complex it looks inside. And although the lens is relatively compact, it still has a lot of room for sensors with higher resolution. Even at 60 megapixels, it is still not at its performance limit.

*The advantage of the 24 megapixel sensor is that it has lower image noise. Even at 10,000 ISO the results are still convincing.*
Leica SL3-S, 1/500 sec., f 2, 10,000 ISO, Apo-Summicron SL 2.0/35 mm – I could of course have taken the image with a longer shutter speed, but I deliberately wanted to achieve a high ISO value . Image editing in Lightroom (no reduction in image noise).

The AF hardness test

In the meantime it has become a little brighter. Boat captain Toni has arrived. He steers his boat with great sensitivity so that I can easily photograph and film Andrina in the water while she swims. I set the autofocus to face priority and AF-C, and I'm amazed at how accurate the autofocus works, even when only Andrina's swimming cap is visible. Here is an example:

41 images in 2.2 seconds: Although the AF conditions are not easy, the SL3-S's autofocus works well. That's exactly how I wanted it. And here is another sequence from the bike training:

The film features

Leica has already introduced a new function in the SL3 that initially irritated me a bit, but which I no longer want to be without: I can create different film profiles and then change them in the menu at lightning speed: For example, I can set a 6K profile with 30 fps, a 4K profile with 60 fps, a Full HD profile with 120 fps (small downside: 120 fps with 4K is unfortunately possible not) etc. Of course I can also give the profiles different codecs. When filming, I can switch between these profiles at lightning speed. Small wish for Leica: Currently the profiles are simply numbered, but it would of course be great if you could assign individual names to the profiles, e.g. “Interview”, “Sport”, “Slow Motion” or similar.

BTS: While Andrina crawls elegantly, I hang over the edge of the boat to film her. For better control of the image section, I mounted my Atomos Ninja as a control monitor. But I recorded all the clips in the camera onto the CF Express B card (Photo: Marco Huber)

The little test film

For my little movie, I film practically everything at 59.94 fps / L-Log / 4:2:2 / 600 Mbit/s. A normal SD card can no longer handle this; you have to insert a CF Express B card. Like the SL3, the SL3-S has one slot for normal SD cards and one for CF Express B cards. In my opinion, this makes sense because you can still use your SD cards, but you have the option of working with the CF Express B cards for demanding filming.

I film a sequence with FHD in 120 fps and then upscale it to 4K with Topaz Video AI. When you watch the film, you will notice that this sequence is no different than the sequences filmed in “real” 4K. AI-supported interpolation also opens up new possibilities in the film sector.

During the shoot I consciously switched between film and photo sequences. You can also see this change in the film. I have also included an example of the editing potential with a transition from the unedited RAW file to the final edited image. My brilliant friend Sebastian Bach has composed the music.

Dynamic range of the sensor

In order to test the dynamic range of the sensor, I meet with Andrina again a few days after the shoot. On this second morning there is no rain in sight and a wonderful sunrise rewards us for getting up early. I want to photograph Andrina fully backlit. The crucial question in such a situation is always: with flash or without flash and then brighten it in post-production? Judge for yourself:

With flash:

Without flash

Here is the unedited RAW file without flash. I exposed it so that even in the sun I still have drawing:

*Leica SL3-S, 1/2000 sec., f 3.5, 125 ISO, Apo-Summicron SL 2.0/35 mm, no flash*

And the result after editing in Lightroom:

In Lightroom I brightened Andrina by 3.5 stops, and her face by 4.25 stops. The sensor provides this. Of course, the image noise is somewhat noticeable in the brightened areas of the image. You can correct this using software, but you lose a little detail: Here is a 100% excerpt with and without denoise:

Color management

You can correct colors later in post-production. But it's much more fun when the camera delivers accurate colors. This is particularly important for skin tones. Here is an example of an image straight from the camera, without editing:

*Leica SL3-S, 1/400 sec., f 4, 100 ISO, Apo-Vario-Elmarit SL 2.8-4.0/90-280mm at 111 mm, white balance “cloudy”, completely unedited, slightly cropped*

How many megapixels do humans need?

Finally, a word about the megapixel run, which continues unabated: We are currently in the range of 50 to 60 megapixels for the full-format top models. But how many megapixels do you really need? A little math: Inkjet printers work with a resolution of 200 to 300 dpi. Don't be confused by the high DPI numbers that printer manufacturers sometimes provide. They partially calculate the resolution for each color channel. But for our calculation we use the resolution that Photoshop (or any other image editing software) displays. In my experience, 250 dpi is enough for an optimal result. 250 dpi is 250 pixels per inch (inch). And since one inch is equal to 2.54 centimeters, the resolution for an optimal print is almost exactly 100 pixels per centimeter. This makes the calculation easy: Divide the pixels of your image by 100 and you get the print size that you can print without sacrificing quality. With a 24 megapixel sensor this is 6000 x 4000 px = maximum print size for an optimal print 60 x 40 cm. That's enough in most cases. But I wanted to print bigger. After some tests with interpolation programs, I came to the conclusion that I get the best results with Topaz Photo AI and that I can double the number of pixels in both length and width without the eye noticing any loss of quality. This means: I can interpolate a 6000 x 4000 px image to 12000 x 8000 px. The prerequisite for this is a high-quality source file: To do this, I photograph in RAW, edit the image carefully and then export it as a 16-bit TIF for Topaz. There I upscale the image from 24 to 96 Mpx. Prepared like this, I can print up to 120 x 80 cm - or crop some and still print fairly large. Of course, you have more flexibility with a high-resolution sensor, but you have to accept more image noise in the high ISO ranges and less good film results. In addition, there is a noticeably higher memory requirement on the computer.

*Large printing is possible: Here is my 120 × 80 cm print from the 24 Mpx file. Of course you would have to see the print in the original, that's clear to me.*

Conclusion

Leica did her homework. The SL3-S combines the typical Leica properties with a very powerful autofocus. The SL3-S is the ideal camera for me for reports where I have to take photos in low light and also want to film. If you need the higher resolution, the SL3 is the right choice.

You have to decide for yourself where your priorities lie and whether you need more than 24 Mpx. If in doubt and if your budget allows it, simply buy both cameras. So you have, as we Swiss say, “dä Füfer and s'Weggli” (and an empty bank account ;-)).

And a few more photos from Training Day

Click on the images for an enlarged view. If you then move your mouse over the image, the recording data will be displayed.