Sony is known for making the sensors with the highest dynamic range (DR) in the industry today. In practical terms, this means that the shadow regions of files from Sony sensors are clean and can be "pushed" to reveal lots of usable detail. I compared the Sony sensor from the Pentax K-5 to the Panasonic sensor from the Panasonic GH2 in this DR comparison. We now know that the Olympus OM-D E-M5 uses a Sony sensor, but there haven't been many rigorous demonstrations of E-M5 DR compared to the newer 16MP generation of Panasonic sensors. Our member Jman presented a great comparison of processed E-M5 and GH2 files here, and DHart recently presented a very nice comparison of processed RAW files from his new G5 and OM-D. Having obtained a Panasonic GX1 to go with my E-M5, I spent a few minutes today on a dynamic range comparison. The GX1 isn't Panasonic's newest sensor - that would be the G5. Also, according to DxOmark, the GX1 has almost a stop less dynamic range than the GH2 at their respective base ISOs, so this shouldn't be taken as a comparison of Panasonic's best vs Olympus' best. Nevertheless, these are both high-end Micro 4/3 cameras that I love a lot, and they are the ones I had on hand for testing. Here is the scene I chose to compare, viewed from within Lightroom, Panasonic GX1 file on the left, Olympus E-M5 on the right: Below are 50% crop comparisons of the highlight areas after a 4 stop pull (-4EV) in Lightroom 4.1. Pay no attention to the TV, which can vary in brightness over the course of the exposure. The door and curtains in the back are lit by 12 ceiling lights and are a good subject for judging recovery from highlight clipping. As you can see, the GX1 highlights are more clipped: Below are the shadow areas from the same two RAW files after a 4 stop push (+4EV). Much cleaner, more detailed shadows from the Sony sensor in the E-M5: Test details: Tripod, self timer, Panasonic 14mm f/2.5 lens used at f/5.6 on both cameras, IS off (E-M5). Exposure time for the GX1 was 4s (base ISO 160) vs 3.2s for the E-M5 (base ISO 200). Lightroom sharpening/NR settings were left at default values. Here are the RAW files for your evaluation: http://mu43rawfiles.s3.amazonaws.com/P8200005.orf http://mu43rawfiles.s3.amazonaws.com/P1010264.rw2 What does it all mean? If you push the heck out of your shadows, the E-M5 files hold up better. How often do I do this? Almost never. So infrequently that to me these sensors are basically equivalent. For both low and high ISO in both low and adequate light, both sensors deliver great image quality. On any given day, my choice of cameras comes down to operational issues (eg, GX1 is smaller, OMD has body IS) rather than any differences between the sensor. Of course if you tend to push the heck out of your shadows, then the differences shown here are likely to matter much more to you than they do to me!