Lumix LX100 Dynamic Range and sensor stress test 27 November 2018

LX100M2. You can see by the sharp edged shadow of her shoes that the lady is in direct sun coming through the skylight and falling on her hair. The background is very dark with no direct illumination. RAW capture. With a bit of adjustment to the brightness, highlight, shadow and contrast sliders in ACR a good result has been possible.

One argument often made in favour of cameras with a large sensor is greater dynamic range [DR] (ability to render detail in highlights and shadows).

This is generally true but if the smaller sensor has sufficient DR for the user’s purposes then the old adage “good enough is good enough” applies (actually I just made that up).

LX100M2. Very high subject brightness range here with sun coming through the skylight and falling directly on the people in the right mid section of the frame. I would normally not bother to press the shutter button when the light is like this as a rather unappealing photo would be the result with any camera. However I include it here to show that the LX100M2 can cope with the technical challenge. RAW capture and use of the sliders in ACR to the limit of their range.
Although the file has been heavily manipulated it remains clean and free from visible artefacts. Only minor correction of color fringing was required.

I like to use the LX100M2 for street and documentary photos. These often present the camera with subjects having a very high brightness range which is out of the photographer’s control.

So “good enough” for my purposes means very good.

Here are some pictures which show the capability of the LX100M2 in situations where there is high subject brightness range.

ISO 200, RAW, adjusted in ACR. Subject brightness range was very high. I judged exposure with the zebras.

Using the Zebras for exposure assessment

Lumix cameras have zebras which can be very useful for adjusting exposure to prevent highlight blowout without undue underexposure.

I recommend readers run their own tests but my practice is:

* I set Zebra 1 to 105% for RAW capture.

* I turn the exposure compensation dial down until the zebras no longer flash on the brightest part of the scene.

* I then turn the EC dial back up 1/3 EV step until the zebras just start flashing again. That is my exposure.

ISO 1600 normal exposure edited in ACR. more noise and less dynamic range than ISO 200 with normal exposure.

Sensor stress test

In recent times some camera testers have developed the practice of stress testing sensors to see how they respond to severe under or over exposure with subsequent brightness correction in Adobe Camera Raw.

I am not convinced this is particularly useful but I tried it anyway.

Cameras which use current micro four thirds sensors (21.6mm) have a maximum 12 bit per channel output. Most 43mm (a.k.a. full frame) sensors can output at 14 bits per channel.

This gives the larger sensors greater flexibility for manipulation using the sliders in Camera Raw.

Some reviewers report good results from 43mm sensors with 5 EV steps of underexposure.

This is not feasible with M43 sensor cameras but no matter, they can still make good pictures if normal exposure is used.

ISO 200 underexposed 3 stops. Lightness corrected in ACR.
As you can see this is not a good result.

Conclusion

1. The LX100M2 and recent M43 cameras can make good photos when subject brightness range is very high provided that:

* RAW capture is used.

* Optimal exposure is achieved without blowing out highlights. The zebras are useful for achieving this.

2. In low light increasing ISO at the point of capture gives much better results than underexposing at ISO 200 then using the sliders in ACR to correct image lightness.