It's not clear what the time interval is between the 2 shots taken for HDR purposes. It should be very small since the CX1 is capable of shooting video at 120 frames/sec, so let's say it's 1/120th sec (although it's likely less). In this example, the total time for 2 shots, 4 stops apart, would 1/800th + 1/50th + 1/120th = 1/35th sec (approx).
Yes but to reach a high DR, you need a good exposure (and with a 'good exposure' I mean a good amount of light, not a high ISO with poor light), so I don't think we should look at the 1/120 speed when trying to reach 12EV of DR.
Let's see what the first tests say. The camera has several HDR modes (weak, strong,...). Maybe they don't refer (or not only) to the tone mapping applied to generate the JPEG image, but to the degree of overexposure of the second shot, and hence to the exposure time needed for it.
PS: what do you mean by a second thread? I did a search on CX1 and didn't find any -> I rectify: I see now your thread sorry (the Search engine does not produce any result for 'CX1' though).
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