ISO Max Comparison in the Deep Blue
One of the most challenging filming conditions for those dedicated to underwater shooting is undoubtedly capturing pelagic life. Encountering grey reef sharks or eagle rays at the mouth of Maldivian “passes” is an incredible emotion, but technically, it represents a true test for our GoPros. Here we face two significant physical limits: the depth, which often sees us operating around 40 meters, and the poor water clarity, typical of the currents flowing through these channels. In this scenario, managing light and digital noise becomes the key to obtaining a usable image.
During a dive at Viligili Kandu (Gaafu Alifu Atoll – Vadoo), I conducted a direct comparison between two different ISO Max settings to understand how they affect the final result in low-light conditions.
Here are the two setups used:
GoPro Hero 12, mounted on a handle tray: 4K 8:7 60fps | AWB Auto | Natural Color | ISO Max 800 | EV -0.5.
GoPro Hero 11, fixed to the “Chesty” chest mount: 4K 8:7 60fps | AWB Auto | Natural Color | ISO Max 400 | EV -0.5.
As can be observed in the comparison video, the footage shot with the Hero 11 at ISO 400 is significantly superior to that of the Hero 12 at ISO 800. The sensor, which is the same in both models, generates very evident digital noise (grain) and a less natural color cast when pushed to 800 ISO at that depth, making it all very difficult to recover in post-production. Conversely, by limiting the maximum value to 400, the Hero 11 processor managed to deliver a much cleaner file, with deeper blacks and clearly better overall quality.
We must be honest: at a depth of 40 meters and with reduced visibility, it is difficult to obtain “National Geographic-style” images with such a small sensor. However, this example demonstrates how technical knowledge of your equipment’s limits makes all the difference. A single ISO step can radically change the nature of the shot: the advice is to try not to exceed 400 ISO, although there is no absolute rule. The choice of the maximum value must be weighed based on the scene: in some rare contexts, 800 is necessary to capture otherwise invisible details, while in many others, it is preferable to limit it to 400 to obtain a cleaner file that is easier to work with. Flexibility and field testing remain the best tools for correctly managing light scarcity, without ruling out any settings a priori.
For more information on all GoPro underwater settings for any situation, and to discover the revolutionary GoPro Labs firmware, visit the GoPro Hacks section of my website.