The French website Focus Numerique has published controlled studio testing throughout the ISO series for the Olympus E-M5, Sony NEX-7, Panasonic G3, Nikon V1, and Canon G1X. Link: Test Olympus OM-D E-M5 : gestion du bruit électronique - Focus Numérique Focus Numerique kindly gave me express permission to republish crops from their test images, and I set out to determine whether there is anything to suggest whether the Olympus E-M5 is using the same 16MP sensor as the Panasonic G3. Olympus has not stated whether the E-M5 sensor is made by Panasonic nor given any specifics as to how the sensor differs from the GX1/G3 sensor. I processed the files using Raw Photo Processor (RPP, Mac). If you download the files, they can also be processed using Picasa or Raw Therapee. There is no support yet for E-M5 files in Lightroom or Aperture. The first thing I did was to compare ISO 6400 files. Interestingly, the G3 file looked more "sharpened" than the E-M5 file, which was not the case for the low ISO files. There was nothing to suggest misfocus or shake-induced blur in the E-M5 file, and both sharpening and noise reduction (NR) were disabled in RPP. Furthermore, the difference in apparent sharpening was also evident in Raw Therapee. From this, I can only guess that either the E-M5 is doing on-chip NR at high ISO or the G3 is doing on-chip sharpening. It could also be something related to the way both RAW apps treat those files, even with sharpening and NR disabled in the apps. The bottom line is that the E-M5 file at ISO 6400 had less evident noise but also less evident detail than the G3 file at ISO 6400. Once I sharpened the E-M5 file a bit to try and match the level of apparent sharpening and detail of the G3 file, I got the following 100% crops: Based on the above, I would say that high ISO performance is nearly identical. It's close enough that we could well be looking at two files from the same sensor when you consider that I am using a RAW processor that doesn't officially support the E-M5 and having to do extra processing in Photoshop to get the levels, colors, and apparent sharpness to roughly match up. The next thing I set out to test was dynamic range (DR), which is a bear to test properly. With current cameras, DR is primarily determined by the amount of detail-obscuring noise in the shadows. Cameras with high DR are those that have clean shadows which can be "pushed" during processing to bring out usable shadow detail. To try and get a sense of DR, I took the base ISO RAW files for each camera (ISO 160 for the G3 and ISO 200 for the E-M5) and first looked to see if the highlight clipping was similarly recoverable in each file. Thanks to the carefully controlled testing by Focus Numerique, this seems to be the case. Given matched highlight headroom, we can then look at the pushed shadows to get a sense of relative DR. I pushed the low ISO files by 4 stops for each camera and then tried to match colors/brightness/levels using the other available controls in RPP as well as I could (with mixed success). Below are 100% crops from the two shadow areas of those files: I'm not sure what to make of those. My first impression was that there is more apparent detail in the E-M5 pushed shadows, but there really isn't a whole lot in it. In summary, using available files with limited RAW support, I see very little performance difference between the Olympus E-M5 sensor and the Panasonic G3 sensor. To me this is a good thing because the G3 sensor is excellent. However, to those looking for a breakthrough in DR with the E-M5, I don't think you'll find it in the RAW files.