Trivia - there is more than one way to control flash exposure !

Discussion in 'Lounge' started by anonzzz, 9 Jan 2020.

  1. anonzzz

    anonzzz Moderator

    Staff Member Lifetime Gold Gold Member No Limit
    Joined:
    13 May 2018
    Messages:
    1,205
    Likes Received:
    21,023
    Trophy Points:
    1,790
    Let us have a little fun with a simple trivia. Say I have an a7iii (max sync speed 1/250s, base ISO 100 but can go down to ISO 50) and an Off-Camera-Flash with the following settings.

    1/125s @ f/2.8 @ ISO 100 with flash currently at 1/2 power

    I currently have the perfect ambient exposure but my flash is 2 stops too dark. How do I correct it just by changing the settings above? :)
     
    anonzzz, 9 Jan 2020
    #1
    NanaNikon and Kocaman like this.
  2. Kocaman

    Kocaman Professional

    No Limit
    Joined:
    28 May 2019
    Messages:
    1,134
    Likes Received:
    6,184
    Trophy Points:
    458
    What lens do you have? f2.8 zoom or f 1.2/1.4/1.8 primes? That will change your possible options.
     
    Kocaman, 9 Jan 2020
    #2
    NanaNikon and anonzzz like this.
  3. anonzzz

    anonzzz Moderator

    Staff Member Lifetime Gold Gold Member No Limit
    Joined:
    13 May 2018
    Messages:
    1,205
    Likes Received:
    21,023
    Trophy Points:
    1,790
    Okay, say 1.4 prime. :)
     
    anonzzz, 9 Jan 2020
    #3
    NanaNikon and Kocaman like this.
  4. Kocaman

    Kocaman Professional

    No Limit
    Joined:
    28 May 2019
    Messages:
    1,134
    Likes Received:
    6,184
    Trophy Points:
    458
    Ok right, here goes....

    Current settings: 1/125s @ f/2.8 @ ISO 100 with flash currently at 1/2 power
    Scenario: Correctly exposed ambient but flash exposure 2 stops too dark

    1/250 f2 iso 100 1/1 flash power
    1/250 f2.8 iso 200 1/1 flash power
     
    Kocaman, 9 Jan 2020
    #4
    NanaNikon and anonzzz like this.
  5. anonzzz

    anonzzz Moderator

    Staff Member Lifetime Gold Gold Member No Limit
    Joined:
    13 May 2018
    Messages:
    1,205
    Likes Received:
    21,023
    Trophy Points:
    1,790
    Thanks @Kocaman ! You nailed it again. In summary, there are also 3 ways to control flash power (just by using the settings alone).

    1) Changing flash power (very obvious)
    2) ISO/Shutter (limited by max sync speed and hand/motion blur)
    3) Aperture/Shutter (limited by max sync speed and how wide the aperture can open)

    I usually max out Option 2 first to maximize my flash power, then Option 1. Again, not normally Option 3 since it changes the artistic nature (bokeh) of the shot. :)
     
    anonzzz, 9 Jan 2020
    #5
    NanaNikon likes this.
  6. Robert

    Robert Apprentice III

    Joined:
    3 Mar 2018
    Messages:
    112
    Likes Received:
    417
    Trophy Points:
    41
    Distance of flash to target. 2x Distance = -2 Stops
     
    Robert, 9 Jan 2020
    #6
  7. anonzzz

    anonzzz Moderator

    Staff Member Lifetime Gold Gold Member No Limit
    Joined:
    13 May 2018
    Messages:
    1,205
    Likes Received:
    21,023
    Trophy Points:
    1,790
    True, but we are just focusing on just changing the settings here. :)
     
    anonzzz, 9 Jan 2020
    #7
    NanaNikon and Kocaman like this.
  8. Kocaman

    Kocaman Professional

    No Limit
    Joined:
    28 May 2019
    Messages:
    1,134
    Likes Received:
    6,184
    Trophy Points:
    458
    Yep and not changing the quality of light :)
     
    Kocaman, 9 Jan 2020
    #8
    NanaNikon and anonzzz like this.
Similar Threads
  1. anonzzz

    Trivia - there is more than one way to control ambient light !

    anonzzz, 9 Jan 2020
    Replies:
    8
    Views:
    2,074
    Kocaman
    9 Jan 2020
  2. Antsz

    How come there's is no Capture One 24

    Antsz, 29 Apr 2024
    Replies:
    6
    Views:
    1,433
    Antsz
    29 Apr 2024
  3. Jupiter

    Photography-on-the.net is dead - There goes another one

    Jupiter, 9 Mar 2024
    Replies:
    3
    Views:
    649
    Jupiter
    9 Mar 2024
  4. anonzzz

    Trivia - Using a fixed ND filter like a variable ND filter

    anonzzz, 9 Jan 2020
    Replies:
    27
    Views:
    5,715
    puppetwarp
    26 Jan 2020
  5. joeflies

    Is there a course that teaches the Yousuf Karsh style?

    joeflies, 8 Oct 2020
    Replies:
    3
    Views:
    1,095
    joeflies
    8 Oct 2020
  6. visualsoft

    < Yellow Images > Is there any folk member of this website?

    visualsoft, 11 Oct 2020
    Replies:
    2
    Views:
    1,081
    visualsoft
    11 Oct 2020
  7. mrlulhahhah

    Just wanted to take a minute to say thanks!

    mrlulhahhah, 18 May 2020
    Replies:
    0
    Views:
    766
    mrlulhahhah
    18 May 2020
  8. cassini

    Happy Thanksgiving 2019 to all!!!

    cassini, 28 Nov 2019
    Replies:
    4
    Views:
    813
    Daukness
    28 Nov 2019
  9. mrlulhahhah

    Happy Thanksgiving to all those who celebrate!

    mrlulhahhah, 25 Nov 2020
    Replies:
    1
    Views:
    789
    Don Corleone
    27 Nov 2020
  10. supersonicmegaritter

    A big thank you to every user

    supersonicmegaritter, 23 Sep 2025
    Replies:
    0
    Views:
    287
    supersonicmegaritter
    23 Sep 2025
Top