We shot green screen with the A7S in both Slog2 and Cinema gammas. When compared to the GH4 4K footage shot with the Natural profile, we preferred the cleaner look of the GH4 4K (which also provides 444 when sampled down to 1080p). The A7S isn't too shabby, it's just that the 4K GH4 looks better after keying. When the Shogun is released, we'll try the A7S again in 4K.