Better autofocus needed shooting into lights (Leica 50mm 1.4, SL2-S vs. Panasonic S5II w/Leica 50mm 2.0 APO)

[LraStn]

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Apologies for the long title! I have a very specific problem. 

I am a wedding photographer, shooting all Leica bodies (Sl2-S, Q, Q3, M10, M6) and lenses with the exception of Panasonic L mount 70-200 2.8.

As has been discussed here before, autofocus while shooting into backgrounds lights is a huge challenge. I've mainly encountered this using the SL 50mm 1.4 lens. It WILL not focus on people dancing if there are small lights behind them, which often happens at weddings such as cafe lights, videographer lighting, or other decor lights.

I'm trying to determine my best path forward to achieve focus in these moments. Does anyone know if the 50mm SL 2.0 APO focuses better than the 1.4 shooting into lights?

I'm also strongly considering selling my back up/fourth SL2-S body in favor of the Panasonic S5 ii, which I have read about here having a much better AF system. Ha Photo attached showing the best focus I was able to achieve recently with my SL2-S and 50mm 1.4. I shot *a lot* of frames of the first dance and parent dances, and vey few were usable. So frustrating! My Q3 wasn't much better in this scenario, although it is doing exactly what I need it to do with exit shots and getting those in focus in rapid fire succession with people walking towards me. 

 

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[Luke_Miller]

In the case of a bright background, the contrast detect auto focus system will often focus on something in the background rather than the subject.  In the posted shot the background is significantly brighter than the subjects.  What has worked for me in similar situations is going to spot metering which meters on the focus point.  In the above image, if the focus point is on the face of the male subject the exposure (and contrast) will be increased and there is a better chance of achieving focus.  It is important to be using spot (single focus point) focus rather than field or tracking that use a larger number of focus points.  They will invariably find something in the background with higher contrast.  There is a bit of flair in the posted image that likely affects autofocus performance by reducing subject contrast. If you were not using the lens hood you might consider doing that. I find having the focus assist active is useful in seeing what the camera is focused on.

I have good luck with autofocus using my SL and SL2 bodies.  But there are times, like in the above situation, when my normal settings would not work.  The trick is noticing that and finding a solution.

I have the 50 SL Lux and it is amazing.  It has the reputation of being a bit slow to focus, but that has not been an issue in my use.  With the SL 2 bodies I don't think a different lens will resolve this issue.  In this photo there is a backlighted subject plus flair.  Pretty much a worst-case scenario for contrast detect autofocus.  Increasing exposure on the male's face will help.  I think this is a situation where the phase detect autofocus (S5 II or SL3) might be the solution if what I suggested above does not help.

Edited August 30, 2024 by Luke_Miller

[Olaf_ZG]

Great reply Luke.

[Stuart Richardson]

I think it is probably worth it to contact Leica (perhaps someone here has a good contact to the SL team), as it seems that your issue is both highly specific and technical, but also quite professional in nature. It would probably help the community in general if you brought attention to this particular AF deficiency. Perhaps they can improve it or offer advice.

[Jean-Michel]

The OP does not indicate which AF setting he is using. With a total of 4 SL2s bodies and assorted other cameras, one would assume that the he has a reasonable knowledge of focus and exposure.

The posted image shows more subject blur than mis-focus. The floor tiles below the couple are more or less in focus. None of the bright light spots are anywhere close to be in focus, so those are not the cause of any mis-focus. To me, this is this is simply a mater of not knowing how to focus  relying blindly on autofocus will inevitably lead to this type of images.

Luke Miller is correct. Using spot focusing will let the photographer to be much more precise as to what or who is in focus.

You also need to know when to press the shutter release.. In my very early days of photography, when I was sent to do weddings with a maximum of 24 sheets for the entire wedding —brides home, church, group, reception hall—, I had to make sure that the first dance showed two happy faces, and not, as in the posted image, inappropriately positioned hands. Pose the couple if you have to, nice result guaranteed., and way more less deleting useless images.

Back to the OP's question: none of your issues are camera or lens related, just use the proper technique to frame and expose.

 

[Luke_Miller]

I took the liberty of playing with the OP's image. It appears focus was on the bride's left shoulder.  The very bright light to the right of the couple makes me think it is a video light. The side of the groom's face towards the light is blown out.  Focus was not perfect, but probably not too bad in that lighting.

 

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[jaapv]

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Run Topaz Photo AI over it and it is perfect. 

[LraStn]

On 8/30/2024 at 1:17 PM, Luke_Miller said:

In the case of a bright background, the contrast detect auto focus system will often focus on something in the background rather than the subject.  In the posted shot the background is significantly brighter than the subjects.  What has worked for me in similar situations is going to spot metering which meters on the focus point.  In the above image, if the focus point is on the face of the male subject the exposure (and contrast) will be increased and there is a better chance of achieving focus.  It is important to be using spot (single focus point) focus rather than field or tracking that use a larger number of focus points.  They will invariably find something in the background with higher contrast.  There is a bit of flair in the posted image that likely affects autofocus performance by reducing subject contrast. If you were not using the lens hood you might consider doing that. I find having the focus assist active is useful in seeing what the camera is focused on.

I have good luck with autofocus using my SL and SL2 bodies.  But there are times, like in the above situation, when my normal settings would not work.  The trick is noticing that and finding a solution.

I have the 50 SL Lux and it is amazing.  It has the reputation of being a bit slow to focus, but that has not been an issue in my use.  With the SL 2 bodies I don't think a different lens will resolve this issue.  In this photo there is a backlighted subject plus flair.  Pretty much a worst-case scenario for contrast detect autofocus.  Increasing exposure on the male's face will help.  I think this is a situation where the phase detect autofocus (S5 II or SL3) might be the solution if what I suggested above does not help.

Thank you so much for this suggestion, Luke. I appreciate your thoughtfulness in the response, and I will test it as soon as possible. If memory serves, I have tried all the focus modes in this situation over the years I've had this lens (got it in 2020), but I will be more scientific in testing them. For this shot I was in field mode with the lens hood, as I always use it. I have also ordered the S5ii as it it a comparatively low cost experiment in my testing. I will report back. Did you use an AI sharpener in this photo with the edits you made? I do have one, I can't recall the name offhand, but it's not Topaz and I haven't been pleased with it.

Edited September 1, 2024 by LraStn

[LraStn]

On 8/30/2024 at 5:05 PM, jaapv said:

Run Topaz Photo AI over it and it is perfect. 

I'll try it, although what I want it to actually achieve focus while shooting but if this saves my bad shots here I will certainly be happy. Thanks! 

[LocalHero1953]

2 hours ago, LraStn said:

I'll try it, although what I want it to actually achieve focus while shooting but if this saves my bad shots here I will certainly be happy. Thanks! 

Exactly the reason I use it!😇

[Luke_Miller]

7 hours ago, LraStn said:

Thank you so much for this suggestion, Luke. I appreciate your thoughtfulness in the response, and I will test it as soon as possible. If memory serves, I have tried all the focus modes in this situation over the years I've had this lens (got it in 2020), but I will be more scientific in testing them. For this shot I was in field mode with the lens hood, as I always use it. I have also ordered the S5ii as it it a comparatively low cost experiment in my testing. I will report back. Did you use an AI sharpener in this photo with the edits you made? I do have one, I can't recall the name offhand, but it's not Topaz and I haven't been pleased with it.

I started with the SL bodies a little over two years ago, so Contrast Detect autofocus is relatively new to me.  All my previous experience was with Nikon Phase Detect.  With Phase Detect I found autofocus performance was relatively independent of exposure.  I find the opposite true of Contrast Detect.  Unless exposure at the point of focus is reasonably correct autofocus can struggle.  I suspect your backlighted first dance photo is one of those cases.  Since the exposure of people in the background is pretty good, I'm guessing the bride and groom were rather dark and you brought them up in post.  The autofocus system was probably struggling to find enough contrast on which to focus. Looking at the image the bride's shoulder appears the sharpest, but the depth of field was not enough to bring the faces fully in focus.  I'm sure you had an aperture setting that would have produced sufficient depth of field for the shot, so possibly the autofocus was hunting and was in a front focus position when the shutter released.

I used Topaz Sharpen Ai in my edit.  I also have Topaz Photo Ai which replaces it but prefer Sharpen Ai because it gives me more control over the sharpening. My edit of your shot was from the small file I was able to capture from your post.  I think a much better job could be done with the original file.  The modern sharpening tools today are a marvel and well worth the investment.  I am reluctant to admit how many images I've saved using them. Even my PDAF bodies can produce a soft image occasionally.  Your incoming S5 II may have focused better with the exposure setting you used with the first dance shot, but if you can nail exposure with your SL2-S you may find that you are happy with its autofocus performance as well.

I did my first wedding shoot in 2003 and understand why this is important to you.  Best of luck.

[MrFriendly]

Judging by your photograph, it looks to me that the focus plane was about half a meter or so in front of the couple (the sharpest point is in the bottom right corner of the image showing the floor).  Unless the couple was moving really fast, I don't think switching to the APO 50 is going to solve your problem.  I have both lenses, and the APO 50 is maybe 20-30% faster.

On my SL2-S, I use Field AF mode when I want more control over the autofocus system.  The Field AF mode has three different sizes, so make sure you pick the appropriate size. Otherwise, I use the Eye/Face/Body Detection mode when shooting people.

Is your Joystick Lock set to Off?  What might be happening here is that you might be locking the focus, and then the subject moves and then you take the shot, which produces the results we see.  When in Multi-Field, Spot, Field or Zone AF mode, if you half press the shutter button to focus, and then press and release the joystick back button, it will lock the focus (the white rectangle turns green).  After that, pressing the shutter button will not refocus, it will continue to take pictures wherever the focus was locked.  You will need to press the joystick back button again to release the lock.  But honestly, it's hard to tell what is going wrong with your case without more details.  

I'm not sure why people are suggesting Spot AF mode as a solution.  Spot AF is best for static subjects (possibly on a tripod).

[Luke_Miller]

15 minutes ago, MrFriendly said:

I'm not sure why people are suggesting Spot AF mode as a solution.  Spot AF is best for static subjects (possibly on a tripod).

Spot metering, not spot autofocus to help with under exposure on backlighted subjects.