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Thread: Question on external flash (attached with photo)

  1. #1

    Default Question on external flash (attached with photo)

    I recently got a EX320 from B&S, thanks to the advice given here.

    I set my flash sync mode to 1/200 and was puzzled. When I use my internal flash, I was only able to achieve 1/20 @ f4 ISO 800. Now, I was able to achieve 1/200 @ f5.6 ISO 400. Is external flash so strong that I can get 1/200 @ f5.6 ISO 400 or am I just getting the wrong exposure?

    Later, I tried using f8 and amazingly, I was able to achieve ISO400 (I thought the ISO is supposed to go up because of the increase in aperture? Is it because the flash is firing at a stronger strength now since it is f8?)

    Lastly, I turned the head of the flash 90 degree and captured a shot. To my dismay, I realised the photo turned out to be wrongly exposed. Shouldn't the flash and camera be intelligent enough to know I have turned the head up and compensate the exposure accordingly? Thanks in advance.







  2. #2

    Default Re: Question on external flash (attached with photo)

    For this answer, you need to look into the EOS Flash Bible:

    http://photonotes.org/articles/eos-flash/

  3. #3

    Default Re: Question on external flash (attached with photo)

    Your exposure is ok, that's the wonder of ettl. It will compensate for the settings accordingly.


    For the bouncing of flash, I not sure if ettl will be able to calculate the flash power with the varying angle of the flash head. Based on my manual flash usage, you certainly need more power as you are diffusing the light now, to create a more flattering image.

  4. #4
    Moderator catchlights's Avatar
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    Default Re: Question on external flash (attached with photo)

    Quote Originally Posted by maisatomai View Post
    I recently got a EX320 from B&S, thanks to the advice given here.

    I set my flash sync mode to 1/200 and was puzzled. When I use my internal flash, I was only able to achieve 1/20 @ f4 ISO 800. Now, I was able to achieve 1/200 @ f5.6 ISO 400. Is external flash so strong that I can get 1/200 @ f5.6 ISO 400 or am I just getting the wrong exposure?

    Later, I tried using f8 and amazingly, I was able to achieve ISO400 (I thought the ISO is supposed to go up because of the increase in aperture? Is it because the flash is firing at a stronger strength now since it is f8?)

    Lastly, I turned the head of the flash 90 degree and captured a shot. To my dismay, I realised the photo turned out to be wrongly exposed. Shouldn't the flash and camera be intelligent enough to know I have turned the head up and compensate the exposure accordingly? Thanks in advance.


    other than reading the link Mod DM show you, this will help you also, Photography Notes For Newbies





    please refer to the link Mod DM shows you.

    #1, this is due to your camera setting for flash, you can override it
    when you are with internal flash, your camera meter is factoring the ambient light, so it make the exposure with slower shutter speed if the ambient light is very dim.
    when you use the external flash, the camera did not factoring the ambient light, it work between 1/60 to 1/250 (depends on your camera highest sync speed)

    #2, needless to say external flash is much powerful then internal flash, and your flash have TTL mode, it will meter the flash light tru the lens

    #3, when the light bounce on any surface, it will alter the WB of the light, the camera may not be able to compensate accordingly even it is on Auto White Balance.
    Shoot to Live, Live to Shoot
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  5. #5
    Moderator Octarine's Avatar
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    Default Re: Question on external flash (attached with photo)

    Quote Originally Posted by maisatomai View Post
    I set my flash sync mode to 1/200 and was puzzled. When I use my internal flash, I was only able to achieve 1/20 @ f4 ISO 800. Now, I was able to achieve 1/200 @ f5.6 ISO 400. Is external flash so strong that I can get 1/200 @ f5.6 ISO 400 or am I just getting the wrong exposure?
    A wrong exposure would be quite obvious, right? Either too dark or too bright. But since your image looks quite ok the exposure is fine. The exposure triangle with flash allows multiple combinations of aperture, ISO and flash power (note: shutter speed is not relevant) to achieve the same result. The camera will send a pre-flash and calculate from there.
    Your first settings tell me that you either work in Manual or in Av mode. Please read the link provided, you'll notice (or you can try) that in P the camera works differently. In order to do a structured tests you need to fix certain parameters, change one and watch the result.

    Lastly, I turned the head of the flash 90 degree and captured a shot. To my dismay, I realised the photo turned out to be wrongly exposed. Shouldn't the flash and camera be intelligent enough to know I have turned the head up and compensate the exposure accordingly? Thanks in advance.
    The White Balance is off. When you bounce flash to the ceiling then the flash gets reflected with a colour cast of the ceiling. If your camera uses Auto WB or even Flash WB then the result is off. Adjust your WB accordingly.
    EOS

  6. #6

    Default Re: Question on external flash (attached with photo)

    Ah yes, when bouncing flash, take note of the colour of the surface you are bouncing the light off as most of the time, the bounced light will take the colour of the surface. Also, you need to be careful of the colour of the ambient light too when using flash, because the camera can only correct the white balance of the overall scene, and not the individual light from the ambient and flash. At times you will need colour gel to match the flash light colour with the ambient light colour, or else you will end up with very weird or extreme white balance in your photos.
    Last edited by tecnica; 7th September 2011 at 10:16 AM.

  7. #7

    Default Re: Question on external flash (attached with photo)

    Quote Originally Posted by tecnica View Post
    Ah yes, when bouncing flash, take note of the colour of the surface you are bouncing the light off as most of the time, the bounced light will take the colour of the surface. Also, you need to be careful of the colour of the ambient light too when using flash, because the camera can only correct the white balance of the overall scene, and not the individual light from the ambient and flash. At times you will need colour gel to match the flash light colour with the ambient light colour, or else you will end up with very weird or extreme white balance in your photos.
    Thanks for all replies. I just did a test again in AV with ISO 100, F/22, 1/200. The exposure was wrong (very dark) and the camera did not tell me that. I feel that is quite dangerous as I may end up with all underexposed photo at the end of the day (the lcd screen is quite small to tell sometimes).

    I tried the constant LED for video. Is the video overexposed?

  8. #8
    Moderator catchlights's Avatar
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    Default Re: Question on external flash (attached with photo)

    Quote Originally Posted by maisatomai View Post
    Thanks for all replies. I just did a test again in AV with ISO 100, F/22, 1/200. The exposure was wrong (very dark) and the camera did not tell me that. I feel that is quite dangerous as I may end up with all underexposed photo at the end of the day (the lcd screen is quite small to tell sometimes).

    I tried the constant LED for video. Is the video overexposed?
    you flash does not have UNLIMITED flash power,
    no flash has UNLIMITED flash power.
    Shoot to Live, Live to Shoot
    www.benjaminloo.com | iStock portfolio

  9. #9

    Default Re: Question on external flash (attached with photo)

    Quote Originally Posted by catchlights View Post
    you flash does not have UNLIMITED flash power,
    no flash has UNLIMITED flash power.
    But the problem is that the camera is not telling me that it does not have enough flash power to take the photo and therefore gave me the wrong exposure. Any way the camera will be able to tell me that or is it I need to see for myself?

  10. #10

    Default Re: Question on external flash (attached with photo)

    Quote Originally Posted by maisatomai View Post
    But the problem is that the camera is not telling me that it does not have enough flash power to take the photo and therefore gave me the wrong exposure. Any way the camera will be able to tell me that or is it I need to see for myself?
    You judge it yourself. You are the user, the camera is just a tool.

    At such extreme settings, even the 580EX2 will tell you that it needs a break.
    Last edited by tecnica; 7th September 2011 at 01:13 PM.

  11. #11
    Moderator catchlights's Avatar
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    Default Re: Question on external flash (attached with photo)

    Quote Originally Posted by maisatomai View Post
    But the problem is that the camera is not telling me that it does not have enough flash power to take the photo and therefore gave me the wrong exposure. Any way the camera will be able to tell me that or is it I need to see for myself?
    the flash WILL tell you it is out of range ONLY after the shot is taken.
    Shoot to Live, Live to Shoot
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    Moderator Octarine's Avatar
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    Default Re: Question on external flash (attached with photo)

    Quote Originally Posted by maisatomai View Post
    But the problem is that the camera is not telling me that it does not have enough flash power to take the photo and therefore gave me the wrong exposure. Any way the camera will be able to tell me that or is it I need to see for myself?
    Taken from the link provided by DM, here exact position:
    http://photonotes.org/articles/eos-f...ex3.html#range
    The second type of range warning is built into the FEL feature with type A bodies. If the lightning bolt icon in the viewfinder blinks when you set FEL then you know that you don’t have enough flash output to illuminate the subject correctly.
    Note: All current EOS xxD and xxxD models fall into the category 'A bodies' as explained in the document. Please take your time reading it, nothing that you easily browse through between a coffee and a doughnut. In addition, your manual should have a comment about 'out of range' warning for flash.
    EOS

  13. #13

    Default Re: Question on external flash (attached with photo)

    Thanks I will read all links provided

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