One problem with digital cameras is ‘noise’ in an image caused by using a too high ISO setting. Many photographers try to keep their ISO set low to avoid this noise.
A not always publicized feature of some digital cameras is a thing called dual conversion gain that can allow you to use a higher ISO with little extra noise penalty. The chart below shows the noise to ISO setting for my Canon R5.
You can see the noise climbs from ISO 100 to around ISO 300 and then drops sharply at ISO 400 before ascending once more. This shows that ISO noise is not always linear when using a dual gain sensor. This means that this camera can use ISO 400 to ISO 1000 and expect the equivalent noise as when using ISO 100 to ISO 300.
You can check the noise to ISO for you camera here… https://www.photonstophotos.net/Charts/RN_ADU.htm
