SL3-S AF-C & Tracking Accuracy - Noticeably Better Than The SL3?

[geronimosan]

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As much as I love the images from the SL3, especially with the 61MP sensor, I am wholly underwhelmed by the AF-C/Tracking accuracy and performance. Even shooting my dog at a slow trot around the yard delivers maybe a 50% hit rate, combined with a 4FPS translates to very few usable and meaningful captures.

The SL3-S is touted as the "fastest" Leica camera, but it's not so much the FPS speed that is the issue for me, it is the AF-C/Tracking accuracy.  I'm miffed at such an expensive SL3 having an AF that is really only great at single shot immobile subject AF, and then the prospect of having to drop another ~$6k for a 24MP camera simply to be able to capture somewhat mobile subject photographs. I don't shoot video, so the SL3-S purchase would be purely for a camera that compensates for lack of AF-C/Tracking capability of the SL3, and at the loss of 40% MP (Even the Z9 shoots at 40'ishMP).

So, before I drop money on the SL3-S just to get the AF-C/Tracking capabilities that should have been better on the SL3 to begin with, does anyone have any real world experience in directly contrasting the SL3 and SL3-S AF-C/Tracking accuracy and performance and can speak to how, if at all, noticeable the difference is between the two cameras?

Thank you in advance!

[jiggyb21]

I have seen this question come up and be asked a few different ways and this is definitely the closest to the how I would ask it myself. My use case is similar in that I also don’t shoot video. After moving over from Canon, I first bought the SL2-s before adding the SL3. For the first time in years I didn’t own a single camera with even passable AF-C. At the time the LUMIX S5ii was so cheap I bought one because of the good reviews and that is barely passable.  Even shooting a bird on a perch or my dog in the yard produces lackluster results.  It sure would be nice to have an L-mount camera with decent autofocus to accompany my SL3. 

[Photoworks]

 

[Photoworks]

My test shows the same AF performances, the SL3s do better in frame rate and electronic shutter.

Important is to use the correct mode. People and Animals work best. Different lenses perform differently too.

the tracking box is not so exciting, it loses to the subject.

But if you want a sports camera get something else!

[geronimosan]

Thanks, that’s a great video explaining how auto focus works in the SL3 series. I’m really looking forward a direct real world contrast in the accuracy and performance between the SL three and the SL3S.

 

I do, however, disagree with the video where it states the animal mode is the same as body I human mode, but just for animals. The body face mode actually recognizes human faces and eyes, but the animal mode does not recognize animal faces or eyes. In fact, in my extensive testing with the SL3, what I have found is that a large box is put around the entire animal and the focus point as usual somewhere in the middle of the animals body. This means whenever I am using shallow depth, the field the middle of the animals body is in focus and the face is always out of focus. Another disappointment with the Leica SL3 auto focus system.

[Pedrocolonia]

My way: Leica SL2 AFS for stills and sometimes MF for action. Canon AFC for sport/action. 
 

Peter
 

[tom0511]

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I have asked this in another thread but not yet found an answer:

Besides the accuracy of focus I am interested about the delay in the viewfinder. I read elsewhere that the SL3/SL3-S when shooting burst does not show real time life view anymore, but shows always the last image taken in the viewfinder instead. if this is the case (what I don't know) it means you see what you have shot and do not see what is happening right now in the viewfinder. If you shoot action where direction and movements change a lot (I shoot handball for example) this delay could mean a real disadvantage to a) capture the moment and b) have a feeling if you captured the moment.

I would really be interested to compare a SL3-S to my Canon which I still keep for sports.

I did feel the AFC of the SL3 (which I own) has improved over the SL2-series. I don't own a SL3-s so I can share any experiences in this regard. I am very interested in the answers. 

[Hanno]

17 hours ago, geronimosan said:

 I'm miffed at such an expensive SL3 having an AF that is really only great at single shot immobile subject AF

 

 

Edited March 8 by Hanno

[jaapv]

6 hours ago, geronimosan said:

Thanks, that’s a great video explaining how auto focus works in the SL3 series. I’m really looking forward a direct real world contrast in the accuracy and performance between the SL three and the SL3S.

 

I do, however, disagree with the video where it states the animal mode is the same as body I human mode, but just for animals. The body face mode actually recognizes human faces and eyes, but the animal mode does not recognize animal faces or eyes. In fact, in my extensive testing with the SL3, what I have found is that a large box is put around the entire animal and the focus point as usual somewhere in the middle of the animals body. This means whenever I am using shallow depth, the field the middle of the animals body is in focus and the face is always out of focus. Another disappointment with the Leica SL3 auto focus system.

Actually animal eye detection works well on Panasonic. Leica should be able  to implement it on the SL3S in due course. 

[LD_50]

4 hours ago, Hanno said:

 

 

The aviation photography being done here is nearly static for just about everything shown. They are most often flying parallel to the subjects so the relative motion is nearly zero. This isn’t much of a test for AF or continuous shooting. 

[Hanno]

7 hours ago, LD_50 said:

The aviation photography being done here is nearly static for just about everything shown. They are most often flying parallel to the subjects so the relative motion is nearly zero. This isn’t much of a test for AF or continuous shooting. 

Thank you ! I needed a laugh 😂

Edited March 8 by Hanno

[LD_50]

2 hours ago, Hanno said:

Thank you ! I needed a laugh 😂

I’m not sure what’s funny about pointing out this isn’t a video about AF or continuous shooting (obviously, given it’s an SL3 video). It’s a video about creative vision and framing, great locations, and hard work producing great results.  

[jiggyb21]

On 3/8/2025 at 10:00 AM, LD_50 said:

The aviation photography being done here is nearly static for just about everything shown. They are most often flying parallel to the subjects so the relative motion is nearly zero. This isn’t much of a test for AF or continuous shooting. 

Precisely

[Ken Abrahams]

Nick Rains video dropped yesterday and he explains the AF for SL3S. Notably I find the Eye Body detection mode in AFC tracking,  super fast. There are other combinations and settings to configure for best results. Ken   

 

[LD_50]

4 hours ago, Ken Abrahams said:

Nick Rains video dropped yesterday and he explains the AF for SL3S. Notably I find the Eye Body detection mode in AFC tracking,  super fast. There are other combinations and settings to configure for best results. Ken   

 

This video is an hour of menu settings. There is one small portion where Rains moves his face around the frame with eye/face AF active. Yes it looks quick on the screen, but there are no photos taken to show it actually focused properly.

My SL2-S shows the boxes over face and eyes that keep up with motion as well but often misses focus when I review the final image. It just can’t actually keep up with motion. This with my fastest AF lens being the 24-90.

While I expect the SL3-S to be much better (due to PDAF implementation) there is nothing in this video that demonstrates the performance of the AF system. 

Edited March 12 by LD_50

[RustyBug]

My question is basically the same as others, but I might ask it differently.

What am I trading 61MP > 24MP for?
I think it's easy enough to understand that fewer pixels to process means I can have a higher frame rate total, or a higher frame rate for a given bit (14 vs. 12), if FPS is my goal for improvement (i.e. "faster").

But, does the choice for 24MP vs. 61MP gain an actual quicker, more responsive AF acquisition for the SL3-S vs. the SL3.  My understanding is that both have PDAF, so the addition of PDAF to the SL3-S is an improvement over the SL2-S for AF, but is the SL3-S an improvement over the SL3 for focus acquisition. 

My "gut" tells me that they are using the same PDAF technology in SL3 and SL3-S, so acquisition capability is going to be the same.  Frame rate will be speedier, but acquisition responsiveness will be essentially equal.

Is there anything we know that suggests otherwise, regarding the acquisition difference between the SL3-S vs. the SL3?
Note:  References to "get a Sony / Canon / Nikon / Panny" for sports camera's aren't helpful in determining a choice / decision between the SL3-S vs. SL3 ... which, seems to me to boils down to the difference of MP vs. FPS (i.e. equal AF acquisition performance in both SL3-S and SL3).  Or, is there a tangible difference in AF acquisition between the SL3-S vs. SL3.

I have no interest in comparing to Sony / Canon / etc. and complaining that the SL3 and SL3-S aren't up to best in class AF-C ... just trying to understand which of the SL3 or SL3-S offers in the quid pro quo of things between those two choices (if I decide to upgrade from my SL2-S).

Edited March 12 by RustyBug

[hoolyproductions]

1 hour ago, RustyBug said:

What am I trading 61MP > 24MP for?
 

My very subjective view on this, based on being a prior owner of SL2-S (and briefly SL2), now having both the SL3 and the SL3-S.

I should say up front that most of my photography is (i) landscape/cityscape (where autofocus performance of any camera of the last 15 years is more than enough for me) and (ii) music photography, where improved face AF (with multiple faces) would be very desirable to me - but the venue where I most often shoot has very low light levels that I think even a state of the art Sony camera would not do well.

• In very low light I feel that the SL3-S is giving me noticeably better noise performance, but not so much to be a deal breaker. I would be 'ok' with the SL3. The level of improvement compared to the SL2 is IMO astonishing
• Regarding AF, I have personally not noticed any difference between the SL3, SL3-S or the prior SL2-S. Maybe its a result of the type of photography I do, or maybe others have a better ability to distinguish small difference.
• Similarly I have not noticed any difference in AF speed with different lenses. Some users here have found e.g. the SL Summicron to be faster at focussing than the APO summicron (due to less weight of glass to move). I was shooting with my Summicron SL last Sunday and could not feel any difference (but it was in very low light). 

So far, the 'bottom line' for me is that I wll continue to use the SL3-S for lower light music photography and the SL3 for everything else. This is the complete opposite of how I used my SL2-S and SL2 (SL2-S for almost everything, SL2 when shooting in decent natural light). The other main difference is of course the file size. I don't need 60mp for my music photography and the SL3-S files are that much quicker to edit/process. For everything else I really appreciate the 60mp - even when I don't intend to crop or print large I like to have all those details in the image so I can inspect and enjoy them - especially in landscape/cityscape shots.

And just for fun, attached one picture from last Sunday where I did manage to aquire focus in time (for several shots I had to switch to manual focus). SL3-S, 90mm APO summicron, ISO 25000, f2, 1/60s

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Edited March 12 by hoolyproductions

[Photoworks]

In My tests  SL2-SL3-SL3s

SL3 and SL3s have the same AF

in AF-S  the focusing performance is the same in all 3 cameras, SL2-SL3-SL3s uses contrast AF for that.

the only benefit of SL3 and SL3s is the PDAF, this is only active in AF-C, and you can see a big improvement over the SL2.
 

Are there any other improvements to the camera? after 5 years, I hope so, and yes!

[LD_50]

2 hours ago, RustyBug said:

My question is basically the same as others, but I might ask it differently.

What am I trading 61MP > 24MP for?
I think it's easy enough to understand that fewer pixels to process means I can have a higher frame rate total, or a higher frame rate for a given bit (14 vs. 12), if FPS is my goal for improvement (i.e. "faster").

But, does the choice for 24MP vs. 61MP gain an actual quicker, more responsive AF acquisition for the SL3-S vs. the SL3.  My understanding is that both have PDAF, so the addition of PDAF to the SL3-S is an improvement over the SL2-S for AF, but is the SL3-S an improvement over the SL3 for focus acquisition. 

My "gut" tells me that they are using the same PDAF technology in SL3 and SL3-S, so acquisition capability is going to be the same.  Frame rate will be speedier, but acquisition responsiveness will be essentially equal.

Is there anything we know that suggests otherwise, regarding the acquisition difference between the SL3-S vs. the SL3?
Note:  References to "get a Sony / Canon / Nikon / Panny" for sports camera's aren't helpful in determining a choice / decision between the SL3-S vs. SL3 ... which, seems to me to boils down to the difference of MP vs. FPS (i.e. equal AF acquisition performance in both SL3-S and SL3).  Or, is there a tangible difference in AF acquisition between the SL3-S vs. SL3.

I have no interest in comparing to Sony / Canon / etc. and complaining that the SL3 and SL3-S aren't up to best in class AF-C ... just trying to understand which of the SL3 or SL3-S offers in the quid pro quo of things between those two choices (if I decide to upgrade from my SL2-S).

I cannot provide any user experience to answer your questions. I can though point out a few differences between SL3 and SL3-S.

SL3-S has 779 PDAF points compared to only 315 on the SL3.

SL3-S also has a faster sensor readout speed than SL3.

Whether these result in better AF speed I’m not yet sure. I’m still waiting for a video from anyone shooting a challenging subject with AFc and tracking and high frame rate with SL3-S.

 

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[LD_50]

39 minutes ago, Photoworks said:

In My tests  SL2-SL3-SL3s

SL3 and SL3s have the same AF

in AF-S  the focusing performance is the same in all 3 cameras, SL2-SL3-SL3s uses contrast AF for that.

the only benefit of SL3 and SL3s is the PDAF, this is only active in AF-C, and you can see a big improvement over the SL2.
 

Are there any other improvements to the camera? after 5 years, I hope so, and yes!

I’ve seen this claim repeated on the forum multiple times, that SL3 and SL3-S only use CDAF in AFs. I’ve also typically seen it mentioned that Leica does not and will not specify how/when CDAF and PDAF are implemented.

Is there a source for this claim? Is there some experimental evidence that indicates PDAF is not used in AFs?