S-Log2 or S-Log3 are functions optimised under the assumption that grading will be performed in the post-production process.
Before grading, videos recorded with the S-Log2 or S-Log3 gamma have more noticeable noise in dark areas compared to videos recorded using other gammas. If the noise is still significant even after grading, it may be reduced by recording with a brighter setting and grading down to the appropriate brightness later.
There is a corresponding decrease in dynamic range when you record with a brighter setting. We recommend checking the image quality including grading in advance by test-shooting when using S-Log2 or S-Log3.
For more details about how S-Log works, visit the Help Guide for Creators Web page.