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Thread: Flash question...

  1. #21
    Moderator Octarine's Avatar
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    Default Re: Flash question...

    Quote Originally Posted by Mustank View Post
    actually i am taking pictures of my 2 boy (6 and 8) playing......they move very very fast, no 1/250 cannot.....they dont stay still for me to shoot....and i dont want them to....they think they are ironman, shiong here, shiong there, jump here jump there, fire here fire there......the younger one has lots of expressions, he really think he is iron man.....i want to capture these expressions and his funny poses....if i ask him to pose, he doesnt want and even if he does so, usually cim one......
    to say the truth: because they are running over the place at home and dont stay in one spot, i didnt see any point in setting up any proper lighting . all i did was to get the 2 flash to fire at the ceiling. end up, i get the picture but boring boring lighting......but no choice.......
    In a different thread somebody mentioned chocolate And maybe lowering the exposure to comics and such things... My uncle never had any issues capturing my three cousins while they were busy with their favourite hobbies
    EOS

  2. #22
    Moderator daredevil123's Avatar
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    Default Re: Flash question...

    You need to understand the concept of flash duration.

    From what I am reading, I am sure that your shutter frame is not fully open at 1/250.
    For speedlights, the less power is fired, the shorter the flash duration. When you are firing at TTL, you are probably firing at much lower power than 1/4 power, so the flash duration is shorter, causing insufficient light to light up the entire frame. There could also be a slight sync problem with your Di866.

    Remember though, for Studio flash, it is the reverse, the more power you use, the shorter the flash duration.

  3. #23
    Moderator daredevil123's Avatar
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    Default Re: Flash question...

    BTW, when your shutter speed is starting to hit the edge of the limit like 1/250, doesn't HSS automatically kicks in?

  4. #24

    Default Re: Flash question...

    Quote Originally Posted by daredevil123 View Post
    BTW, when your shutter speed is starting to hit the edge of the limit like 1/250, doesn't HSS automatically kicks in?
    Maybe he did not enable FP sync in his cam?
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  5. #25
    Moderator daredevil123's Avatar
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    Default Re: Flash question...

    Quote Originally Posted by sjackal View Post
    Maybe he did not enable FP sync in his cam?
    Maybe.

    One other thing, the max sync stated in manuals sometimes is not accurate in real life...

    I have seen 7D falter at 1/250 in the studio, and only ok with 1/200.

    TS should read this..
    Strobist: Know Your Sync

  6. #26

    Default Re: Flash question...

    Quote Originally Posted by daredevil123 View Post
    You need to understand the concept of flash duration.

    From what I am reading, I am sure that your shutter frame is not fully open at 1/250.
    For speedlights, the less power is fired, the shorter the flash duration. When you are firing at TTL, you are probably firing at much lower power than 1/4 power, so the flash duration is shorter, causing insufficient light to light up the entire frame. There could also be a slight sync problem with your Di866.

    Remember though, for Studio flash, it is the reverse, the more power you use, the shorter the flash duration.
    Thank you so much! I experiment more. I realized the more I push the di866mk1 (any mode) the more black I see (keep wacking 1/4 or up the fec)

    I suspect it maybe a bit spoil already because my di622mk2 don't have these problems. I try not to do hss because I know that one eat a lot of power and I burnt my di866mk1 once already

  7. #27

    Default Re: Flash question...

    Quote Originally Posted by daredevil123 View Post
    Maybe.

    One other thing, the max sync stated in manuals sometimes is not accurate in real life...

    I have seen 7D falter at 1/250 in the studio, and only ok with 1/200.

    TS should read this..
    Strobist: Know Your Sync
    That is true. Same with triggers too and studio lights (maybe older units?)

    In studio on white steamless I actually shoot at 1/125 instead of the max sync of 1/250. Because for every 50 shots, maybe 3 to 5 shots will have sync problem. 1/200 and 1/160 reduce the ratio down. Since I dont have problems of ambient, 1/125 totally eliminates the problem.

  8. #28
    Moderator daredevil123's Avatar
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    Default Re: Flash question...

    Quote Originally Posted by JasonB View Post
    That is true. Same with triggers too and studio lights (maybe older units?)

    In studio on white steamless I actually shoot at 1/125 instead of the max sync of 1/250. Because for every 50 shots, maybe 3 to 5 shots will have sync problem. 1/200 and 1/160 reduce the ratio down. Since I dont have problems of ambient, 1/125 totally eliminates the problem.
    1/125 is a little slow... other things also matter, like having fresh batteries in all the equipment. Getting better triggers also matter, some triggers are notoriously slow.

  9. #29

    Default Re: Flash question...

    Quote Originally Posted by daredevil123 View Post
    1/125 is a little slow... other things also matter, like having fresh batteries in all the equipment. Getting better triggers also matter, some triggers are notoriously slow.
    i just bought yongnuo yn622c flash trigger (1 set) at first i also thought maybe the trigger got problem, but i tried the trigger on the di622mk2, after many fires (ettl +1 1/3 fec), still ok leh,

    then i mount the 866 on camera body, still got black band. then i try put the di866 on optical slave mode (manual), also got balck band.....but it is ok, i 50% write off this flash already , can only use as support light

    i wanna thank you and clubsnap. from here i learnt:
    1) put camera manual mode (1/250 - kids super fast but i dont want to go hss), (iso 100 - for the cleanest photo), (f4 - f5.6: lens highest resolution aperture)
    2) then lup 2-3 flash to mmet the extreme amount of light requirement of (1/250, iso100, f4)

    i know this trick only can do indoor, but hey, it is good enough for most of my needs!

    i also go and get 2 cheap small umbrella and i tink i will only use them once so far, i very satisfied with the result!

    heh heh heh...i say until like flash is magic bullet

  10. #30
    Moderator daredevil123's Avatar
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    Default Re: Flash question...

    Quote Originally Posted by Mustank View Post
    i just bought yongnuo yn622c flash trigger (1 set) at first i also thought maybe the trigger got problem, but i tried the trigger on the di622mk2, after many fires (ettl +1 1/3 fec), still ok leh,

    then i mount the 866 on camera body, still got black band. then i try put the di866 on optical slave mode (manual), also got balck band.....but it is ok, i 50% write off this flash already , can only use as support light

    i wanna thank you and clubsnap. from here i learnt:
    1) put camera manual mode (1/250 - kids super fast but i dont want to go hss), (iso 100 - for the cleanest photo), (f4 - f5.6: lens highest resolution aperture)
    2) then lup 2-3 flash to mmet the extreme amount of light requirement of (1/250, iso100, f4)

    i know this trick only can do indoor, but hey, it is good enough for most of my needs!

    i also go and get 2 cheap small umbrella and i tink i will only use them once so far, i very satisfied with the result!

    heh heh heh...i say until like flash is magic bullet
    Actually you got some flash principles/techniques wrong..

    1. you do not need your shutter speed to be fast, because the flash duration is fast, and it will freeze the action for you even if your shutter speed is slower.
    2. You should not shoot at ISO100. ISO performance on cameras are very good nowadays. If you have a moderately newer camera, your ISO can be pushed to at least ISO800 with negligible noise. WIth ISO higher, your flash do not have to work as hard. This will give you faster flash refresh rates, longer battery life, as well as faster flash duration (for speedlights only) that will freeze action better in (1).

  11. #31
    Moderator catchlights's Avatar
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    Yes, agreed with mod dd123, just shoot at Iso 800, you'll gain two stops power.
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  12. #32

    Default Re: Flash question...

    Quote Originally Posted by daredevil123 View Post
    Actually you got some flash principles/techniques wrong..

    1. you do not need your shutter speed to be fast, because the flash duration is fast, and it will freeze the action for you even if your shutter speed is slower.
    2. You should not shoot at ISO100. ISO performance on cameras are very good nowadays. If you have a moderately newer camera, your ISO can be pushed to at least ISO800 with negligible noise. WIth ISO higher, your flash do not have to work as hard. This will give you faster flash refresh rates, longer battery life, as well as faster flash duration (for speedlights only) that will freeze action better in (1).
    Thank you so much!

    Whoa!!!! i never knew about (1)!!! tonight i go home try 1/200 and so on progressively to see where the is confortable minimum.....

    my one is 40d.... i notice that if i shoot at iso800 and above, there will be artifacts if i sharpen in dpp. but i notice that if i shoot at iso100, i cant see any artifacts even if i sharpen to +10....maybe i shoot iso400

    later i go and google what is 40d optimum iso my son just call me this morning and told me that my 2nd set of yongnuo trigger has arrived, damm cant wait to go home today!

  13. #33
    Moderator catchlights's Avatar
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    Keep your exposure spot on, it will have less noise issue.
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  14. #34

    Default Re: Flash question...

    Quote Originally Posted by Mustank View Post
    Thank you so much!

    Whoa!!!! i never knew about (1)!!! tonight i go home try 1/200 and so on progressively to see where the is confortable minimum.....

    my one is 40d.... i notice that if i shoot at iso800 and above, there will be artifacts if i sharpen in dpp. but i notice that if i shoot at iso100, i cant see any artifacts even if i sharpen to +10....maybe i shoot iso400

    later i go and google what is 40d optimum iso my son just call me this morning and told me that my 2nd set of yongnuo trigger has arrived, damm cant wait to go home today!

    Just keep practicing and don't be afraid to try new things. Through mistakes, it's from there we'll learn.

  15. #35

    Default Re: Flash question...

    i ust went to do more read up and watch free tutorial in youtube. good stuff:



    i learnt great new stuff today!!!

    if manual settings on camera produce total black image,

    effective shutter speed = flash duration

    camera shutter speed is no longer the freeze motion factor

    wow!!! i learnt about flash duration today!!! i think i kee siao liao !!!
    Last edited by Mustank; 9th October 2012 at 05:37 PM.

  16. #36

    Default Re: Flash question...

    i must have gotten my flash theory all wrong that it is aperture which controls flash lighting given a fixed flash power . . .
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  17. #37

    Default Re: Flash question...

    Quote Originally Posted by Mustank View Post
    effective shutter speed = flash duration
    camera shutter speed is no longer the freeze motion factor
    That is if the flash is the main light source. if you try 1/200s in bright sunlight, even 1/1 flash power can't really freeze a fast motion.


    Quote Originally Posted by Shizuma View Post
    i must have gotten my flash theory all wrong that it is aperture which controls flash lighting given a fixed flash power . . .
    quick rule of thumb is still, use aperture to control flash power (although it does also affect ambient), shutter and ISO to control ambient lighting (note ISO will also affect flash power).

    For example, if you are on f/5.6 an 1/250s right now - you want to cut flash power by 1 stop but retain ambient - you turn up aperture to f/8 to cut flash by 1 stop, then lower shutter speed by 1 stop to 1/125 to maintain ambient (since raising aperture from f/5.6 to f/8 cuts ambient by 1 stop too).

  18. #38
    Moderator catchlights's Avatar
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    Default Re: Flash question...

    Quote Originally Posted by Shizuma View Post
    i must have gotten my flash theory all wrong that it is aperture which controls flash lighting given a fixed flash power . . .
    aperture control lights enter thru the lens, being flash or ambient.
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  19. #39

    Default Re: Flash question...

    Quote Originally Posted by catchlights View Post
    aperture control lights enter thru the lens, being flash or ambient.
    Yes, and in regards to that ambient; the right shutter speed at a given ISO, shuts off that ambient, or allows it in.
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