Originally posted by biz-engineer you haven't tried at ISO6400, I have compared, I think the complains about K1 II exaggerate, it is made a bigger deal than it actually is, and it means if you are after such details at ISO6400, tripod and electronic shutter are mandatory (same conditions as in the test chart), then I don't see how it makes sense to set ISO6400 with the camera fixed on a tripod. I've asked to provide conditions where high detail and high ISO are simultaneously mandatory and after 3 weeks I still haven't had any answer.
Actually, I
did briefly compare at all ISO levels
The thing is, higher ISO shots from the 5DS R appear sharper and more detailed than at ISO 100... but this is merely perceptual, and is simply because they're noisier. The ISO 100 shot gives a more honest representation of the captured detail.
I don't think there are
many situations where high ISO and high detail are simultaneously necessary - but I can see why, for instance, bird photographers shooting in less than ideal light with fast shutter speeds could benefit from that combination. For a 36MP camera, the K-1II does an excellent job of retaining
enough detail at higher ISO settings, based on the test shots...