Olympus E-M5: Dynamic Range - RAW

I posted in February a blog on E-M5 dynamic range. At that time it was about jpeg images. Now we have two popular and well known converters supporting E-M5, which enabled me to take another look with raw files. These converters are Lightroom 4.1 (Release Candidate 2) and CaptureOne 6.4.

This graph shows the same E-M5 and E-P3 dynamic ranges (orange and red) for jpeg images as shown in my previous blog. They are actually measured from raw files converted into jpegs in Olympus Viewer 2. This software emulates in camera jpeg process, which means I can tweak the jpegs to show optimal jpeg quality.

Blue and green lines  show what can be achived from E-M5 and E-P3 raw files. I opened raw files into Lightroom and CaptureOne and measured dynamic ranges at various ISOs. Both software showed almost the same numbers for E-M5. With E-P3 there was slight variation at some ISOs but there was no trend in favor of either software. What you can see here is the average performance of these software. The biggest and maybe most important difference was for E-M5 at ISO 200. With Lightroom I was able to read a 12.6 EV dynamic range and with CaptureOne it was 12.0EV.  At ISO 400 they both gave the same 12EV.

When you look at this graph, please do not take exact numbers too seriously. Look at trends E-M5 versus E-P3 and raw versus jpeg. While saying that I think it is no mistake to have E-P3 dynamic range at 10EV, which is the same as DxO Mark result for the same camera. Also two well respected software giving practically same numbers (sans ISO 200) for E-M5 should be no mistake either.

I have now shot a few thousand images with E-M5. Those images show the same trend in real life situations compared to E-P3 as this graph.

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Olympus E-M5: Dynamic Range

I shot a test series with E-M5 and E-P3 to determine their relative dynamic or tonal ranges at various ISOs. Table below shows my findings.

These values are calculated from images opened in Olympus Viewer 2. This software opens RAW images but it actually emulates in-camera JPEG process. I used here lowest contrast and normal curve.

Dynamic range is not defined unambiguously. Here I used certain contrast edges to decide where detail ends and noise starts. E-P3 curve shows two anomalies: at ISO 800 and ISO 12800, they come from the fact that I shot at 1/3 EV intervals and at those points shadow and highlight exposures happened to have more distance. DxO Mark gives a dynamic range of 10.1 EV for E-P3. It is measured directly from sensor. Here we have more variables and maybe we should use rather the term tonal range. These EV values should not be taken too seriously as absolute ones, they are simply a result of certain process.

The important result is: E-M5 has markedly better dynamic range, in image files it is around 2 EVs. I´m having a bit difficult time looking at this graph, but this is what I see in highlights and shadows. So much wider range of details can be found in E-M5 files in Viewer 2 software. ISO values in table are nominal. E-P3 ISO values are actually lower than nominal, E-M5 sensitivities are closer to nominal values.

Addendum: Conclusion

After a well slept night I thought that I need to write a few more lines because the above result is, well, remarkable. I have seen news about an interview where Olympus spokesman said that there is a 30% improvement in DR. What does 30% mean? Is it 30% of doubling DR which is 0.3 EV? Is it 30% more above 10 EV, which is 3 EV? Anyway: If you shoot JPGs or use Olympus Viewer 2, my test tells that you get a lot more. You can get more details to work with for some 0.3 steps in highights and 1.7 steps in shadows when compared to similar settings and exposure and in E-P3. This result may or may not be true with third party RAW processors. I will come back to it later.

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