SL3/Q3 exposure preview glitch

[Luke_Miller]

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In doing some online research I find this subject has come up regularly starting with the original Q.  I have to assume this "feature" is a design decision rather than a bug.  As near as I can tell it is only experienced in full manual mode (shutter speed, aperture, and ISO fixed).  The problem is Exposure Preview is disabled during autofocus operation. This creates the possible situation where light levels change while tracking the subject causing over/under exposure, but the EVF does not show it. This gives the photographer no opportunity to change settings on the fly.  The consensus seems to be that Leica uses the data stream to the EVF for autofocus. By disabling Exposure Preview during autofocus in Manual Mode, Leica is ensuring enough light for accurate autofocus should a significant light level change occur.  In this case an in focus, but under/overexposed image would result. Hopefully correctable in post.  Of course the photographer can keep an eye on the exposure meter readout in the EVF during tracking and make any exposure adjustments needed.  Not saying this is good or bad. But it seems to be what is going on.

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[Luke_Miller]

The above post also applies to my SL2.

[Steve Babuljak]

1 hour ago, Luke_Miller said:

In doing some online research I find this subject has come up regularly starting with the original Q.  I have to assume this "feature" is a design decision rather than a bug.  As near as I can tell it is only experienced in full manual mode (shutter speed, aperture, and ISO fixed).  The problem is Exposure Preview is disabled during autofocus operation. This creates the possible situation where light levels change while tracking the subject causing over/under exposure, but the EVF does not show it. This gives the photographer no opportunity to change settings on the fly.  The consensus seems to be that Leica uses the data stream to the EVF for autofocus. By disabling Exposure Preview during autofocus in Manual Mode, Leica is ensuring enough light for accurate autofocus should a significant light level change occur.  In this case an in focus, but under/overexposed image would result. Hopefully correctable in post.  Of course the photographer can keep an eye on the exposure meter readout in the EVF during tracking and make any exposure adjustments needed.  Not saying this is good or bad. But it seems to be what is going on.

Thanks for digging into this Luke. Yes it definitely seems like it is intentional. I’m just not clear as to why, as it doesn’t aid the photographer in any way (well except proper auto focus). And it looks like the SL3 will do the same. I believe the LUMIX cameras do this too as it is their tech. 

It’s such a bummer as I’d really love to switch over but don’t see how I could tolerate this occurring while I shoot. 
 

it’s also odd that in the other auto based modes it doesn’t need to do this. 

Did you get this info from a Leica official or just come to that conclusion?

[Luke_Miller]

48 minutes ago, Steve Babuljak said:

Did you get this info from a Leica official or just come to that conclusion?

Just my analysis of various threads in different forums.  I don't know if the info that autofocus uses the data stream that feeds the EVF is correct, but that seems consistent with what we are seeing.  My impression is that Leica is saying "In any of the autoexposure modes there will be enough light for accurate autofocus, but in manual exposure mode we can't assume that, so we will turn off exposure preview when autofocusing."

[Steve Babuljak]

On 3/23/2024 at 6:34 PM, Luke_Miller said:

Just my analysis of various threads in different forums.  I don't know if the info that autofocus uses the data stream that feeds the EVF is correct, but that seems consistent with what we are seeing.  My impression is that Leica is saying "In any of the autoexposure modes there will be enough light for accurate autofocus, but in manual exposure mode we can't assume that, so we will turn off exposure preview when autofocusing."

Hoping to meet with a Leica rep this week, so hopefully some answers soon!