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Flash exposure compensation OMD EM1 Mk2

Discussion in 'Olympus Cameras' started by RichardC, Jan 11, 2019.

  1. Hi everyone.

    I have a new toy - an STF-8 Macro Twin Flash.

    I am ignorant when it comes to the Olympus TTL system. To date, all of my flash photography has been metered manually with a hand held meter with two or three heads, soft boxes etc.

    I'm wanting to use my 60mm macro, hand-held with my new flash. I want to take advantage of the Olympus TTL system.

    My first results seem okay, but on taking a photo on A mode, when the histogram is bunched to the left and things look a bit dim, I'd hoped that by dialling in, say, +0.7 or +1, then the histogram would head towards the right and the preview would look better exposed.

    It doesn't. Dialling in an extra stop. via exposure compensation does absolutely nothing. Aperture is f2.8 so plenty of power is available. Flash is set to auto (TTL).

    I reset the camera to factory settings. No change.

    What am I doing wrong?
     
  2. comment23

    comment23 Mu-43 Top Veteran Subscribing Member

    671
    Aug 26, 2016
    Hampshire, UK
    Simon
    Toggle the 3rd item down in Menu—>Gears—>F

    It looks like this:
    7A1DED7C-85ED-4111-B1E8-E02097A266C1.jpeg
    Subscribe to see EXIF info for this image (if available)

    And is set to OFF by default.
     
    • Appreciate Appreciate x 2
  3. Brilliant. Thank you very much! Working as expected!
     
  4. ....although OFF by default seems daft to me :) 
     
    • Agree Agree x 1
  5. genesimmons

    genesimmons Mu-43 Top Veteran

    593
    Feb 12, 2017
    i believe my sony is the same way,,,,ttl was behaving weird with eposure comp, changed it like above and boom,,,,weird
     
  6. Clint

    Clint Mu-43 Hall of Famer Subscribing Member

    Apr 22, 2013
    San Diego area, CA
    Clint
    It actually makes sense - having the flash set to TTL means it will measure the light reflecting from your subject and adjust the output of the flash to get a correct exposure. So if you add or reduce the cameras exposure compensation, TTL is going to meter that and adjust accordingly.

    When you have that option set to "On" the camera adds the exposure compensations you have set from the camera and the flash together and then TTL adjust accordingly.
     
    • Informative Informative x 1
  7. rich.smith

    rich.smith Mu-43 Regular

    43
    Dec 21, 2011
    Off is the way I prefer it. I am used to treating the ambient exposure separate from the flash exposure and I like to be able to adjust compensation for each separately. Were you adjusting ambient exposure comp or flash exposure comp? If the former, I can understand why you weren't seeing any change. Likely your exposure would have been dominated by the flash. Adjusting ambient exposure would have no effect.
     
  8. Apologies - I missed this. You are right, I was adjusting ambient exposure compensation. No effect I was indoors. The setting above implies that flash exposure compensation is added to (and it seems, aligned with) ambient exposure compensation.

    I need to experiment outdoors in good light to appreciate the usefulness of TTL flash.

    If I set everything manually at ISO 200, I'm getting a well exposed image at 1:1 with my 60mm set at f8 and STF-8 set to 1/8 power - an easy set of numbers to remember. Just need to dial extra in for light objects, or turn it down for dark :) 
     
  9. rich.smith

    rich.smith Mu-43 Regular

    43
    Dec 21, 2011
    Correct. I just did a quick test. E-M1 with the FL-LM2 flash. When the setting is off, changing the ambient exposure compensation to -2 ev has no effect on the brightness of a photograph. Changing the flash exposure compensation to -2 ev dims the brightness. If I change the setting to on, the ambient exposure compensation of -2 ev dims the brightness to look just like adjusting the flash exposure compensation.

    I can see the convenience if you shoot with flash in A mode or S mode. You get the ability to adjust exposure compensation the same way whether you are shooting with a flash or not. But, this only makes sense if the photograph will be dominated by the flash exposure.

    Also, I shoot flash in M mode and on my cameras, I cannot use exposure compensation in M mode. So, I have to rely on adjusting the flash exposure compensation anyway.

    IMO, this is where separating the two exposure compensation settings is critical. I often use flash for fill and almost always dial in -1 ev flash exposure compensation to make the fill flash look more natural. I want the ambient exposure compensation separate from the flash exposure compensation.

    Sounds like a good solution indoors. Outdoors, you make need to adjust your approach if you want to get the background correctly exposed as well as the subject. The flash light fall off is very quick and you'll need to rely on the ambient light to get the background exposed properly. If you set -2 ev to correctly expose a black subject, you may not want the background under exposed by 2 stops. Obviously, this is only an issue if you are shooting in A mode.
     
    • Appreciate Appreciate x 1
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