Use focus peaking
This handy feature makes it easy to calculate depth of field
Most mirrorless cameras and the Live View feature of some DSLRs include a feature called ‘focus peaking’. This works by detecting edges of high contrast in the scene and highlighting them. As well as showing areas that are technically in focus, it will also highlight edges that are sharp and therefore within the depth of field. This is a generally reliable method and quicker and easier than calculating hyperfocal distance.