Gain can rescue dark images, but it also amplifies noise along with them.

Gain is very much like the last lifeline for a dark image—but it doesn’t come for free. As you brighten the image, you also amplify the noise along with it. The result? It looks brighter, but in reality, the edges become coarser and the details get dirtier.

What did the gain do?

Gain essentially amplifies the signal. As a result, the image brightness increases—but so do the random fluctuations already present in the sensor itself. Consequently, what you see isn't just changes in brightness; you also notice graininess, color noise, and edge jitter.

Why is high gain unstable?

High gain does indeed help in low-light scenarios, but it’s more of a fallback option rather than the preferred solution. As long as there’s still room to adjust the ambient light, aperture, and exposure time earlier on, you shouldn’t crank up the gain too high right from the start. Once noise has been amplified, it becomes much more costly—and time-consuming—to try to clean it up later.

On-site parameter tuning sequence

If a problem can be solved with light, don’t resort to boosting the gain just yet. If it can be resolved with aperture, don’t rely on gain to compensate. Saving gain for last often results in a cleaner overall image. For projects involving recognition and measurement, “brightness” is never the sole objective—what really matters is “stability.”

High gain easily gives people the illusion that, once the image becomes brighter, the problem has been solved. In reality, in many cases, it merely means that the image is “visible”—but not necessarily “accurate.” Once noise starts to appear, edges become coarse, textures get distorted, and subsequent processing becomes even more labor-intensive.

Therefore, a more stable approach is to place the gain adjustment at the very last stage. First, try to address issues optically if possible; if exposure adjustments can resolve the problem, do so first. Only when the brightness still falls short should you resort to gain adjustment as a final step. This way, the image typically comes out cleaner and is better suited for subsequent algorithms.

Gain can boost brightness, but it can’t save details.

When the gain is increased, the image becomes brighter, but noise also increases accordingly. Issues such as jagged edges, distorted textures, and flickering details often aren't caused by the algorithm itself—rather, they stem from the fact that the preceding signal has already been amplified in a noisy or imperfect manner.

The more reliable order remains the same: First, try to solve the issue using light; then consider exposure; and only at the very end should you rely on gain as a last resort. High gain is suitable for remedial purposes but not for use as the primary solution.

High gain is only suitable for backup purposes.

When the gain is increased, the image becomes brighter, but noise also increases accordingly. Issues such as jagged edges, distorted textures, and flickering details often aren't caused by the algorithm itself—rather, they stem from the fact that the preceding signal has already been amplified in a dirty or unclean manner.

So the more reliable order remains this: First, figure out how to solve the issue using light alone; then consider exposure; and only at the very end should you rely on gain as a last resort. High gain is suitable for making corrections but not for serving as the primary solution.

· If it can be solved with light, don't rely on gain just yet.

· If exposure can fix it, don't crank up the gain just yet.

· The gain only takes care of the final breath.

The louder the noise, the more the gain exceeds the threshold.

If you find that the noise is more prominent than the target itself, it means the gain has gone too far. First, step back and check the light and exposure. You can always adjust the brightness later, but once noise starts to appear, it’s very difficult to eliminate—and in the end, it’ll often contaminate the entire workflow.

· If it can be solved with light, don't rely on gain just yet.

· If exposure can fix it, don't crank up the gain just yet.

· The gain only takes care of the final breath.