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Thread: Fill in Flash

  1. #1

    Fill in Flash

    I know there is bags of stuff about this on the web but that is really the problem. I am a little confused since to start with I just want to get some very fundamental basics right. I have tried to use fill flash from my 430EXII both mounted on the camera an on bracket. The problem is try as I might I always seem to blow the highlights on the face. Quite severely in some cases. I have basically used AV mode setting the aperture to the required setting to get the DoF I think I want then letting the camera and flash do the rest (via ETTL). I have tried using FEC with some success but it is very hit and miss. I am sure I am missing something. Does anyone have any easy to follow guidelines. I gather I need to meter the background (spot metering and fix the setting using * I assume??) but I am not sure how this can help.

  2. #2

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    Re: Fill in Flash

    Can you post one or two examples, with exif data intact?

    Normally ETTL II is pretty good - although keep in mind that there's also a minimum distance; any closer and you can get a bad result.

    Really need to be able to see the problem to be able to help much more though.

  3. #3
    CNelson's Avatar
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    Re: Fill in Flash

    I am still at the beginning of the learning curve but this website was very helpful for me:
    http://www.planetneil.com/tangents/f...hy-techniques/

    Chuck

  4. #4
    Daniel Salazar's Avatar
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    Re: Fill in Flash

    you might need to adjust the EV compensation for the flash. Try setting it -1 EV as a staring point and then try until you find what you want.

    It's also important to remember that depending in the backlight you should use + or - EV compensation. It's not the same when using your flash as a fill light when your backlight is the sun or when there is no backlight.

    as Colin suggested, you should post a picture and then we could see where the problem might be.

  5. #5

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    Re: Fill in Flash

    Hello,

    If you're out in daylight the problem might be that the camera can't get the exposure down enough with the aperture that you've selected. When using the flash, the fastest shutter that you can normally get is 1/250 (with a 40D anyway, but it's usually about that). If you have a wide aperture then this might still lead to overexposure. If this is the case, then try turning on the 'safety shift' feature in the custom settings (the 40D has it at least, most of the others would too, although the 400D doesn't). This will allow the camera to override your selected aperture setting if it needs to. As a rough idea, on a sunny day here one will often need to go to F8 or narrower at ISO 100. The alternative is to enable 'high speed sync' on your 430EXII. In this mode the flash will fire a series of pulses while the shutter travels (rather than just one pulse), so it can be used at faster shutter speeds, at which the sensor is never fully exposed at one time. It drains the batteries more quickly but it works for fill flash as long as the range isn't too great.

    Even then you might still benefit from some negative flash exposure compensation. I generally find that about -1 stop is about right.

    Regards,
    Will

  6. #6

    Re: Fill in Flash

    Thankyou all for taking time to provide me with this information. I will work through it all and get some practice shots off at the weekend. In themean time here is an example of one of my problem images.

    Fill in Flash

    Fill in Flash

  7. #7

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    Re: Fill in Flash

    Ah ...

    ... problem is that you haven't got high-speed synch turned on. Got to run for now -- will update thread soon!

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    Re: Fill in Flash

    OK - I'm back

    Problem you have is the same problem Heather had ...

    You've got the camera set for Av mode (so camera sets the shutterspeed) - it's set for 100 ISO (that's fine) - and you've selected an aperture of F5.6 ...

    Using the sunny 16 rule as a guide, if your going to use F5.6 as an aperture then your likely to need a shutterspeed of around 1/800th ... which you'd think that the camera would love to give you - except - with the flash connected it can't allow a shutterspeed any faster than 1/200th (the X-Sync speed), so you've over-exposed the image by 2 stops (approx).

    Solutions ...

    Easy ...

    - Stick to an aperture of no less than 11, or

    - Switch on High-Speed Sync on the flash

    - Use manual mode/metering

    Hope this helps - just let me know if you need more help with this.

  9. #9

    Re: Fill in Flash

    Colin you are a star. Once again you have made sense of things. I can see exactly what I am doing wrong.

    Thanks for all your contributions. I have read them all and they help me in many ways to understand.

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    Re: Fill in Flash

    Quote Originally Posted by Wirefox View Post
    Colin you are a star. Once again you have made sense of things. I can see exactly what I am doing wrong.

    Thanks for all your contributions. I have read them all and they help me in many ways to understand.
    No worries

    Kudos to WillC as well - I've just realised that he posted the answer before I did!

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