How can you control video grain with ISO settings?

Native ISO is super important to know - staying within your cameras capabilities is key to get the best video footage. Every camera at various levels, entry, amateur and professional have varied native ISO and you need to play within that scope

Look up your camera body's "native ISO". Operating within that range (or single value) will ensure little to no noise. Yes, it's possible to have too little ISO depending on the body but that is a less common problem.

Lower ISO for Bright Conditions: In well-lit conditions, use a lower ISO setting (e.g., ISO 100 or 200). Lower ISO values result in less sensitivity to light and produce cleaner, less grainy images. Higher ISO for Low-Light Conditions: When shooting in low-light situations, you may need to increase the ISO setting (e.g., ISO 800, 1600, or higher). This boosts the sensor's sensitivity to light, allowing you to capture usable footage, but it can introduce grain. Use the Base ISO: Every camera has a base or native ISO, which typically produces the cleanest image quality. For many cameras, this is around ISO 100 or 200. If lighting conditions permit, stick to the base ISO for the best results.

There could be two reasons for the noise in your video: The first reason is high ISO. In this case you will need to aim for the native ISO of the camera (this is almost always not the minimum value), in this case you will get a quality picture at the shooting stage. The second possible reason is overheating of the camera. In this case, in addition to noise, hot pixels (burning white or red dots in your image) can be detected. The higher the temperature, the more visible they are. Therefore, to reduce noise at the stage of shooting it is better to aim for the native ISO and not to overheat (or cool down) the camera during shooting

Understand your camera's native ISO setting and stay as close to that as you can. Keep your ISO low in bright situations and use an ND if necessary. If it is dark, take advantage of the lighting in play to put yourself in the best position and increase your ISO when necessary, but understand the trade-off of increased ISO to increased grain.

To make it basic, your ISO controls how sensitive to light the sensor of your camera is. The key to remaining in control of the grain or noise in your image is learning what the "native ISO" is for your camera. Think of the native ISO as the natural or normal sensitivity level for your camera's sensor. When you go to an ISO setting above or below the native ISO, you're making it more or less sensitive than normal. The higher you make the ISO (increasing the sensitivity) the more grain/noise you add. This can also have additional effects on the dynamic range and color of your images. Alternatively, taking the ISO below the native ISO doesn't usually introduce noise, but can decrease the dynamic range of the sensor.

Ideally, you always want to shoot at the "native ISO" of your camera. This is the setting at which you are neither boosting or reducing the sensitivity of the sensor. The native ISO varies from camera to camera. You should be able to find it in the manufacturer provided specs/info. If properly exposed, images shot at this ISO level will be the cleanest images your camera can produce and have the most dynamic range.

Just a step before this and a super useful tip: make sure you're recording 1 to 1.5 stop over normal metering and then represent the shadows in post, It will be the noise killer tip!

A simple way to avoid and prevent grain within video and photo, is to have an optimal lighting setup. A bright key light where possible is a great place to start. Along with using a lower shutter speed where possible (for photography). Or a wider aperture setting (f/1.4, f/1.8 or even f/2.8). Video grain can be fixed in post production, however software has a limit to how effective it is. Grain isn't always a bad thing! A higher ISO, creating more grain can be used as a creative outlook as well.

There are many cameras on the market that boast "Low-Light Performance." However, instead of worrying about spending more and more on cameras that claim to be able to see in the dark, think more about what and where you're shooting. Can you change your composition to allow for more natural light if you don't own a light? Can you move your subject(s) so that they're better exposed with your frame? You can de-noise, colour grade, and cover with digital grain but ultimately, you want to make sure it looks great in production so you can have fun in post-production!