A “tech geek’s” comment inspired by the Sony A7S release…
I appreciate the quality of codec/bitrates of the new Panasonic GH4 (there are several first examples available online), the maturity and all-round versatility of the system, as well as its plethora of great improvements (like the “depth-for-defocus” contrast-detection AF). However, there is one thing on GH4 I have never found to be the most elegant technical solution. Namely, it is rather high megapixel score (16MP).
I do suppose for a motion-stills/video oriented micro 43 camera the optimal resolution would be 12+MP. The arguments are straightforward:
1. 12+MP on a micro 43 sensor is a “native” resolution for the academy DCI 4K standard (4096×2160 pixels) supported by GH4 b.t.w. It means less crop factor (2 vs 2.3) in the 1:1 pixel map video mode, owing to the higher horizontal resolution of the 16MP sensor (4608 pixels). To note: 2 vs. 2.3 crop is noticeably less pleasant for a video maker (!).
2. Higher continuous shooting rates for stills: 30% speed-up in the continuous shooting does matter (!).
3. Slightly lower ISO noise (and slightly higher dynamic range) in the video and pictures’ modes.
For the motion-stills/video-oriented cameras (1) and (2) is much more important than extra 4 MP in stills. B.t.w, I lived a quite happy stills’ live with my G2 – just be thorough with composition and no need to crop :).
There are well-known successful examples of the strategy (“less MP = more speed/IQ”) in the DSLR world (Nikon D4 (16MP/FF), Canon 1D (18MP/FF)… And now – “suddenly” appeared at NAB, the first 4K mirrorless full-frame Sony A7s. The specs are just arriving…
As compared to the GH4, A7s has lower bandwidth/processing power (no on-board 4K (!); 50 Mbps vs. 200 Mpbs for 1K video, UHD (3840×2160) – no full 4K DCI resolution – not clear yet if it will be fixed in the firmware; 4:2:2/8 bits vs. 4:2:2/10 bits etc.) with the advantage in the high ISO of course. Note that A7s has also 14 bit RAW for stills. However I rather applaud Sony for limiting the resolution by 12 MP. It is a very harmonic engineering solution for the motion-oriented camera.
Dreaming forward about 4K on micro 43… I would like to see two lines of Panasonic sensors: 16MP for the stills-oriented cameras and 12MP for the motion-oriented ones. For that I would gladly pay extra. Apparently, Panasonic thought about it more than me. Sadly, they do not follow this path likely due to the high financial burden for maintaining the two lines of the “perfect” sensors on one consumer’s products line. This is in contrast to Sony which always seem to have enough cash to sit on several sits (A7, A7R, A7S, NEX, …) …
PS I do not intend to compare 4K/micro 43 vs. 4K/mirrorless-FF as systems themselves here: the pro/cons are be basically the same as for the stills’ counterparts.