Lumix GH3 Review Part 8, Image Quality

Introduction  Early 4/3 and M43 format cameras struggled with image quality plainly inferior to that available in cameras with APS-C sensors, both DSLR's and Mirrorless ILC's.

Sony to the rescue  With the EM5, Olympus used a sensor made by Sony in preference to previous sensors made by Panasonic.  The result was an immediate improvement in image quality. Olympus used the same sensor on subsequent Pen models and the Lumix design team is rumored to have used the same sensor on the GH3.

Good enough image quality  Regardless of the origins of the sensor, most reviewers find the image quality of the GH3 to be  the same as or extremely similar to that of the EM5.  Most users posting  impressions of personal experience appear to indicate they find the GH3 image quality good enough for most purposes. My own experience is that this is the first M43 camera which I will take with confidence into almost any photographic situation having a high level of expectation that the photos will be correctly focussed and exposed and deliver good enough image quality for magazine reproduction at the very least and often good enough for large poster size prints.

* Looking at RAW conversions straight from Adobe Camera Raw 7.3, I found that in the ISO 3200-6400 range, the GH3 advantage over GH2 was about 2/3 stop less noise. The GH3 advantage over G5 was about 1/2 stop less noise.

* I also found that the default RAW conversion by ACR produced files with noticeably different mid tone and shadow brightness. The GH2 files were the darkest in the mid tones and shadows, and the GH3 files lightest in the mid tones and shadows. The G5 tone curve lay between the other two.  The point here is that to adjust a GH2 file to match a GH3 file in mid tone brightness, I had to use the sliders in ACR to lift the darker tones. Those darker tones contain most of the noise. So the final outcome is that the GH3 improves on the GH2 by one stop of noise in the ISO 3200-6400 range and is 2/3 stop better than the G5.

* Highlights are less often blown out with the GH3 than the other two.

* GH3 colors are more accurate right across the ISO range than the other two.

* Resolution is the same with all three cameras.

* If a particular photo requires substantial highlight and/or shadow recovery in ACR, the GH3 files cope with this better than the other two cameras with less artefacts at the bright end and less noise at the low end.

iDynamic and iResolution  These functions appear as active in the Rec Menu with RAW or JPG files. With JPG files iDynamic applies a negative exposure compensation to the normal exposure for that scene then lifts the dark tones for an end result having better detail in both light and dark tones than a standard single exposure. With RAW files iDynamic just applies the negative exposure compensation and nothing else.

I ran a number of tests with iResolution on different scenes and have to confess I never quite convinced myself that it did anything that I could see.

Dynamic Range  I lack the technical expertise to evaluate this scientifically. In general photography in conditions with high subject brightness range there does appear to be a slight advantage to the GH3, but it is subtle.

I rarely need to resort to HDR strategies with the GH3, even in conditions with very high subject brightness range. There is almost always enough information in RAW files for ACR to give me a satisfactory level of detail in shadows and highlights.

High ISO  With judicious work in ACR I find even ISO 6400 files good enough for magazine reproduction with most subjects.

Summary  You can look up all the technical data at  dxomark.com  or  dpreview.com  and I would  recommend that anyone with an interest in image quality do so. However from a user's perspective the GH3 does a fine job right across the spectrum of imaging conditions from low to very bright light and low to very high subject brightness range.