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Thread: Flash compensation after diffusing it

  1. #1

    Default Flash compensation after diffusing it

    Hi,
    I understand many of us use Stofen Omnibounce or a white card as a diffuser instead of using the flash directly on our subjects to prevent a 'wash-out' effect.

    May I know what is the flash compensation you use after diffusing in indoor/low light situation. Please also specify how do you do your diffusing, since the different modes of diffusing flash means different degree of light loss.

    Thanks.

  2. #2

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    I'm using TTL.

    Some flash units have wide angle adaptors. I know mine has. How do they serve as a diffusor?

  3. #3

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    If you are using ETTL flashes, it should be all automatic. A preflash b4 the main flash measures the amount of flash to fire. Compensation should not be neccessary unless the reading is screwed up.

  4. #4

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    for indoor lowlight events i simply mount the omnibounce and tilt/or shoot straight and set -1 n 1/3 flash comp

  5. #5
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    Quote Originally Posted by yeocolin
    I'm using TTL.

    Some flash units have wide angle adaptors. I know mine has. How do they serve as a diffusor?
    since you are using ttl, there is no need to compensate... the flash will compensate it for you.

  6. #6

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    if you are using digital cam. The best is to review the photo then adjust the flash accordingly to suit your taste.

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    you mean to preview it on the lcd and make your judgement on flash accuracy based on that? i dont think thats a good idea beacuse the lcd on the camera is not accurate enough for one to make such a decision.

  8. #8

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    Hi Ektar25, thanks for the wonderful url!

    Thanks too for the advice of so many others.

  9. #9

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    Quote Originally Posted by showtime
    you mean to preview it on the lcd and make your judgement on flash accuracy based on that? i dont think thats a good idea beacuse the lcd on the camera is not accurate enough for one to make such a decision.
    yes but at least you can differentiate whether you have a underexpose pict by looking at the histogram.

    the tools is there, use it. Better then nothing.

  10. #10
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    i agree on the histogram bit..

  11. #11

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    Quote Originally Posted by clive
    for indoor lowlight events i simply mount the omnibounce and tilt/or shoot straight and set -1 n 1/3 flash comp
    really depends on the kind of event and the space around it.... doesn't work for all situations

  12. #12
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    Quote Originally Posted by showtime
    you mean to preview it on the lcd and make your judgement on flash accuracy based on that? i dont think thats a good idea beacuse the lcd on the camera is not accurate enough for one to make such a decision.
    The review in this context is not so much for judging exposure but for how accurate the flash is, typically, how strongly/accurately lit the foreground (flash subject) is wrt to the entire picture. The histogram is not as helpful in this case bcoz it carries the data of the entire scene mixed in.

    You can still guess which spike in the histogram corresponds to the main subject, but it's hit and miss guesswork when there are multiple spikes, or worse, no spikes.

    Despite its inaccuracy, i would say that using the lcd review is (usually) more useful than the histogram is judging flash accuracy, unless your flash intention is to light the entire scene (ie no background, eg newspaper pinned on wall).

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    Whether u compensate or not even with TTL also depends on how contained an area your subject is in.... just shooting last week in a small dining room and rather dim (tungsten warm light), and I bounced the flash off the ceiling (ceiling about 12-15 feet high, flash head almost vertical) and my shots were very well-exposed (no hotspots)but the whole shot's lighting became like white lighting rather than the warm tungsten light... in this case, me thinks the space was small and the flash was very powerful and so the entire space (read background, foreground) was lit by the flash... not unpleasant but kinda lost the atmosphere....

  14. #14

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    i've noticed on my sigma 500dg super that whenever i use omnibounce or lumiquest, i have to have -1Ev flash compensation to get the same results as flash without any attachment and 0 flash compensation.

    Rather puzzled by it since i tot eTTL shld factor in the omnibounce,,,..

  15. #15

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    I thot iTTL shd do that too ... my experience was the opposite ... shooting at home with SB800 requires +1EV with the diffuser ...

  16. #16
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    Your flash might not be very compatible with the camera body especially the Sigma... or the calibration of the TTL sensor is off. Other factors may be the reflectance and colour of the background, etc and the metering mode of the camera.

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    Quote Originally Posted by HOCL
    I thot iTTL shd do that too ... my experience was the opposite ... shooting at home with SB800 requires +1EV with the diffuser ...

    hey you're not alone. i realised the 550 on the 300d needs +1EV for my needs too.
    Canon 300D, 30D, 5D. 17-40 f4 L, 24-105 f4 L, 70-200 f2.8 L IS

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    Quote Originally Posted by weg
    i've noticed on my sigma 500dg super that whenever i use omnibounce or lumiquest, i have to have -1Ev flash compensation to get the same results as flash without any attachment and 0 flash compensation.

    Rather puzzled by it since i tot eTTL shld factor in the omnibounce,,,..
    u using 300D? on my 300D, i need to +1EV when using the bounce with my sigma 500DG Super. or else my pics will be under. i suppose if u are using the canon EX 550 flashes, it will not have the problem.
    If Life worked on auto mode then manual mode for photography would have never existed. ― Deeksha Mittal

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