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I’ve been reading quite a lot about codecs, compression and how different cameras compress the images coming out of the sensor to output the final video file. I’ve used Canon DSLRs for quite some time and never was disappointed. I trust them really. That was until my GH4 arrived lately. After playing with the GH4’s 200 megabits/s and 50 megabits/s modes and finding that they are identical to my eyes, I kept wondering about how much these numbers really mean when it comes to evaluating codecs, and whether they're worth considering Especially since I’ve been seeing 24 megabits/s 4:2:0 8bit cameras give a comparable image to 800 megabits/s 4:2:2 cameras. So I thought I would test the codecs I have in my Canon 70D DSLR and GH4, to see if they’re similar since they’re the same codec, H.264, same compression rate, and same 4:2:0 and 8 bit, so the extent of compression, based on numbers, should be the same, right? -Please note: I am not comparing the image quality between the Canon and GH4, I am comparing how they both compress their images. -The way I though I would test this, is by taking a full resolution still image and compare that to the video file both cameras output under the same conditions. This should give a good idea on how the sensor output looks (Still) and how the final compressed video looks, thus give a fairly accurate representation of the Codec. Not a scientific test, full of flaws, but gives an idea of what the codec is doing. -I am testing the 1080p codecs, not the 4K one. 1- The Canon H.264 Codec Vs. Full resolution Still - Low ISO (100) '' target='_blank'>> 2- The Panasonic H.264 Codec vs. Full resolution Still - Low ISO (100) '' target='_blank'>> 3- The Canon H.264 Codec vs. Full resolution Still - High ISO (3200) '' target='_blank'>> 4- The Panasonic H.264 Codec vs Full resolution Still - High ISO (3200) '' target='_blank'>> ___________________________________ 1-The Gh4 H.264-compressed files look nearly identical to the original full still image. 2-The amount of destruction the Canon H.264 is doing to the image is simply atrocious! It's interesting to me because they're both H.264, 4:2:0 and 8 Bit codecs and both around 50 mbits/s So why are the results that different in terms of compression? I came to the conclusion that the Codec efficiency, how it's implemented, is much much more important than the spec-sheet numbers. This is why the C100 is giving great H.264 4:2:0 8 bit images, and the same reason why the GH4 image is that incredible. The compression is simply brilliant, with hardly any loss of detail and noise. If any one has any idea why can the same codec be much better in one camera, and much worse in another, please share, It would be nice to know what is the reason behind that efficient compression. Both cameras output from the sensor very comparable image quality and maybe even better on the Canon, it's just that in video, Canon compresses the hell out of that image, and Panasonic doesn't. It's all about the codec, not the sensor or other technology. It's eye opening! *Didn't compare the 4K to save the Canon blushes. The Canon DSLRs are going on ebay, I just can't stand how bad the image is after seeing the GH4's