To make adjustments for all exif fields in your pictures, you can use the script plugin in cPicture to run the ExifTools on your picture selection. Assume the camera date/time is wrong by accident and all pictures are stamped with one week in advance.
This example sets all exif date fields back 7 days.
Create a text file, copy the following content and name it to ExifDate.ps1 and save it in the cPicture.exe folder:

# plugin variables

# console=true displays a console, use this option for scripts with text output

# noexit=true keeps the console open, set to 'false' to have the console closed when processing is done

param (

    -name name
    -file file
    -dir dir
    -width PictureWidth
    -height PictureHeight
    -i sequence number
    -n number of files

    -name c:\picture_folder\picture.jpg
    -file picture.jpg
    -dir c:\picture_folder\
    -width 1024
    -height 768
    -i 1
    -n 4

# exiftool in cPicture installation folder
# "Year:Month:Day Hour:Minute:Second"
C:\cPicture\exiftool.exe -AllDates-="0:0:7 0:0:0" $name

Start cpicture, select your pictures you want to change, select the function module selection and select the script you just created:

Hint: If you use any of the exif functions in cPicture, ExifTools gets automatically installed for you.