It's no secret that the smaller, less expensive, non-SLR-styled Micro 4/3 cameras are the best selling ones. The discounted Olympus E-PL1 and E-PL2 have been at or near the top of the selling charts in Japan for a long time, and from what I have been able to tell from several unofficial sources, the GF2/3, E-PM1, and E-PL3 have also sold well.
A key factor in the high sales of these cameras has been their relatively low price, presumably made possible in part by the use of the first generation 12MP Micro 4/3 sensor (the sensor found in all Olympus Pens plus the Panasonic G1/2/10 and GF1/2/3). There is no explanation other than price for the fact that Panasonic put the 1st gen 12MP sensor in the GF3 despite the fact that the GF3 was introduced after the G3, which featured a newer 16MP sensor.
As a GF3 user, I'm perfectly happy with the image quality I get from this camera, but all things being equal, I would prefer to have the better performing, newer sensor. I don't mind paying extra for it either. What I don't want is the size of a G3 or GH2. The GF3 is my coat pocket camera, so I'm unwilling to go larger to get a different sensor.
When Panasonic announced the GF5, the press release indicated that the new camera featured a "newly developed 12.1-megapixel Live MOS sensor and redesigned Venus Engine". The Venus Engine is the in-camera JPEG processor and therefore not relevant to me as a RAW shooter, but a new 12MP sensor sounded like good news. DPReview's GF5 preview
noted: "Under the hood, the GF5's newly developed 12MP CMOS sensor is an evolution of the one used in the GF3, but with improved circuitry that doesn't block as much light entering the photosite, giving better low light performance".
Sadly, the RAW samples provided by Focus Numerique
show that the GF5 sensor offers little improvement over the GF3 sensor and doesn't come close to the level of the G3. Here are a couple representative ISO 6400 Lightroom 100% crops with default color noise reduction (NR) only:
Compared to the GF3 file, the GF5 file is slightly less noisy but also less detailed, suggesting the possibility of on-chip luminance NR (although we cannot rule out a combination of slight misfocus and improved noise handling).
Note that the G3 is disadvantaged in the above comparison since we are comparing at 100% view rather than matched output size. Nevertheless, it is clearly superior to the GF5 in the level of detail relative to noise.
Panasonic's sensor stratification strategy to date has been as follows: The flagship (at least for video) GH series gets its own sensors. The other high-end cameras (G3 and GX1) get a different new sensor, and the smaller and less expensive cameras (GF3, GF5) get a less expensive, lower performance sensor.
With the exception of the newest model (OM-D E-M5), all of the Olympus Micro 4/3 cameras to date have used the same 1st gen sensor. Before long, we are sure to see replacements for the smallest Olympus bodies, the E-PM1 and E-PL3, and as I read the forums, I can see that many people are counting on these replacements to use the higher performance sensor from the OM-D E-M5. I hope that this will be the case, but it will be a break from Panasonic's strategy if Olympus chooses this route.
The Micro 4/3 system is not about having a cheap alternative to larger systems. Rather, the system exists for those of us who want a smaller, yet still highly capable alternative to larger systems. As such, I hope that the manufacturers will avoid strictly associating "small" with "low end", something which most DSLR makers (excepting perhaps Pentax) have been doing for a long time.
While it's true that many enthusiasts find the smallest of Micro 4/3 cameras to be uncomfortable or cramped, there are others of us who love a very small camera and want the most capable tool possible in that form factor. Of course there needs to be a tiny and inexpensive body for "point and shoot" upgraders, but I believe there is room in the market for an equally tiny and more costly model for enthusiasts.
Panasonic and Olympus would also do well to mind the competition. The entry level Sony NEX cameras use sensors which are only slightly if at all behind the sensors used in their flagship models. In fact, the lower end NEX-C3 and F3 sensors outperform the high end NEX-7 sensor when it comes to edge performance with certain wide angle lenses including the Sony 16mm pancake. The fact that entry level Micro 4/3 cameras offer significantly worse sensor performance than high end models would not be lost on reviewers and could lead to the perception that our system as a whole is more disadvantaged in terms of sensor performance than it actually is.
I hope Olympus kept all of this in mind when choosing sensors for the next generation of their coat-pocketable Micro 4/3 cameras.