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Thread: why canon shutter speed does not change with flash????

  1. #1

    Default why canon shutter speed does not change with flash????

    Hi all,
    Having a canon 450d but whenever i shoot in AV mode, there is no different on the shutter speed regardless my flash is mount or not mount onto the body... Is this the correct way canon body works or isn't some malfunction on my canon body or flash or isn't i miss our some setting??? BTW i am having the same issue using build-in flash....

    The external flash i using is canon 430exII


    Pls help

    Thanks!!!

  2. #2
    Member Linnl71's Avatar
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    Default Re: why canon shutter speed does not change with flash????

    I think your issue is probably due to the flash's sync speed. Different camera has different flash sync speed.

    Not sure about the canon 430exII, but mid range external flashes should have a function called High-Speed Sync (HSS) which allows the camera to adjust its shutter speed to exceed its maximum flash sync speed.

    Read your flash manual and experiment with your flash.

  3. #3

    Default Re: why canon shutter speed does not change with flash????

    Sounds normal for EOS flash.

    Have a look at http://photonotes.org/articles/eos-flash/
    particularly http://photonotes.org/articles/eos-flash/#faq10

    By default, in P mode, the shutter speed is kept to 1/60 or faster -- in most indoor lighting, the system treats the flash is the main source of illumination.

    In Av mode, the camera meters for the ambient lighting, the and flash is treated as a fill light. Your camera should have a custom function to lock the shutter speed to a fixed (1/200, I think) speed in Av mode with the flash on.

  4. #4

    Default Re: why canon shutter speed does not change with flash????

    Quote Originally Posted by teck21 View Post
    Hi all,
    Having a canon 450d but whenever i shoot in AV mode, there is no different on the shutter speed regardless my flash is mount or not mount onto the body... Is this the correct way canon body works or isn't some malfunction on my canon body or flash or isn't i miss our some setting??? BTW i am having the same issue using build-in flash....

    The external flash i using is canon 430exII


    Pls help

    Thanks!!!
    there is a minimum sync speed for using the flash which is around 1/180-1/250 seconds.

    if you are shooting in bright bright light with backlit subjects it is entirely possible that the camera thinks that you are using the flash as a fill-in.

    if you want 100% accurate answer, post up the pictures taken with and without flash mounted, so people can see the conditions. exif intact please.

  5. #5
    Member MobilR's Avatar
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    Default Re: why canon shutter speed does not change with flash????

    For flash exposure, aperture is the primary exposure control. Changing the shutter speed in the range of its maximum synch speed and about 1/50sec won't do anything to your exposure when using a flash. This is because your flash will always fire within that shutter speed.

    In Av mode, therefore, the shutter speed will take an optimum setting chosen by the camera, and stick to it.

  6. #6

    Default Re: why canon shutter speed does not change with flash????

    IMO - practice manual (on cam, not flash) and stick to it for greater control!

    ie - you don't want too fast a shutter else (at night) the ambient light might not register giving you that people are bright but everything else dark look...
    speaking of which you might want to set it to 2nd curtain or slow sync flash..

    you don't want it too slow either due to camera shake.. the flash will freeze whatever it hits..but who knows u might like the effect of line streaks?

    and at least the metering mode would not affect your exposure each time u measure of something too dark..or too light.. pros n cons

    recently want to chop myself having to shoot without flashgun in low light

  7. #7
    Senior Member Diavonex's Avatar
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    Default Re: why canon shutter speed does not change with flash????

    Does shutter speed really matter? Read this:

    http://www.cs.mtu.edu/~shene/DigiCam...TER-speed.html

  8. #8

    Default Re: why canon shutter speed does not change with flash????

    Quote Originally Posted by teck21 View Post
    Hi all,
    Having a canon 450d but whenever i shoot in AV mode, there is no different on the shutter speed regardless my flash is mount or not mount onto the body... Is this the correct way canon body works or isn't some malfunction on my canon body or flash or isn't i miss our some setting??? BTW i am having the same issue using build-in flash....

    The external flash i using is canon 430exII


    Pls help

    Thanks!!!
    Did you set your camera to slow sync or rear sync? Sorry I am Nikon user so may not be using the correct term. By default, cameras are set at 1/60 for AV, P if you do not set as rear or slow sync.

  9. #9
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    Default Re: why canon shutter speed does not change with flash????

    Quote Originally Posted by teck21 View Post
    Hi all,
    Having a canon 450d but whenever i shoot in AV mode, there is no different on the shutter speed regardless my flash is mount or not mount onto the body... Is this the correct way canon body works or isn't some malfunction on my canon body or flash or isn't i miss our some setting??? BTW i am having the same issue using build-in flash....

    The external flash i using is canon 430exII


    Pls help

    Thanks!!!
    Check your flash sync speed setting. One limitation to the flash is that you can't increase the shutter speed faster than the flash syn speed. Normally I will set mine to 1/250s.

    When you are using flash, then the exposure depends on 5 variables : ISO, Aperture, Shutter speed, flash power and the flash to subject distance. The Aperture controls the flash exposure; if over exposed, reduces the Aperture and when under exposed increases the aperture. For Shutter speed, it will not affect the exposure of the subject but rather the ambient of subject. It control the amount of light that enter the camera to make the ambient more brighter if you use a slower shutter speed. But remember, you just cannot go beyond the 1/250s if your flash sync speed is set at 1/250 sec. Hope this help

  10. #10

    Default Re: why canon shutter speed does not change with flash????

    Quote Originally Posted by teck21 View Post
    Hi all,
    Having a canon 450d but whenever i shoot in AV mode, there is no different on the shutter speed regardless my flash is mount or not mount onto the body... Is this the correct way canon body works or isn't some malfunction on my canon body or flash or isn't i miss our some setting??? BTW i am having the same issue using build-in flash....

    The external flash i using is canon 430exII


    Pls help

    Thanks!!!
    Go search on your custom function,
    read something about lock your flash sync speed in AV mode,
    it could be set lock to 1/200 speed (fixed) or changes
    EOS 1DMarkIV,
    Xwife : EOS40D, 5D, 5DMarkII, 7D, SonyA900 | seXytoys :EOS 400D, 450D, 500D, SonyA550

  11. #11

    Default Re: why canon shutter speed does not change with flash????

    That's normal behaviour. For your 450D, the max flash sync speed is 1/200s.

    If you're in Av, Tv, or M modes, the shutter range is 30s to 1/200 sec.
    If you're in P mode or any of the 'scene' modes, the shutter range is 1/60 to 1/200 sec.

    Since you're in Av mode, and I presume you're in a dark or indoor environment, where your current shutter in Av is slower 1/200s, therefore popping a flash or not, will not change the shutter. Unless your current shutter is faster than 1/200s, then popping a flash, the shutter will be dropped down to 1/200s and 'blinking' in the LCD indicator.

    You don't have to use the external flash to experiment. The built-in pop-up flash will do. Try pointing at dark and bright scenes in those different modes (Av, Tv, P, M), note the shutter value, then activate your pop-up flash. Changes or not, depends if your shutter value falls within those range that I mentioned earlier.

  12. #12

    Default Re: why canon shutter speed does not change with flash????

    thanks everyone for the reply
    cos i find it quite weird that when AV mode is selected, shuttle speed is only be fixed to 1/200(in custom function). I tried using nikon demo system before and if i remember correct, when av mode is selected shuttle speed will change according if flash (build-in) is pop up hence if flash is pop up, shuttle speed will be faster and if flash is de-activated shuttle speed will be slower.

  13. #13

    Default Re: why canon shutter speed does not change with flash????

    ya it wouldn't affect much but picture will be blur when aperture is smaller....

  14. #14
    Moderator Octarine's Avatar
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    Default Re: why canon shutter speed does not change with flash????

    Quote Originally Posted by teck21 View Post
    thanks everyone for the reply
    cos i find it quite weird that when AV mode is selected, shuttle speed is only be fixed to 1/200(in custom function). I tried using nikon demo system before and if i remember correct, when av mode is selected shuttle speed will change according if flash (build-in) is pop up hence if flash is pop up, shuttle speed will be faster and if flash is de-activated shuttle speed will be slower.
    The shuttle speed is somewhere around 27,000km/h when entering Earth's atmosphere ... and soon the program will be discontinued.
    Read up about the way Canon cameras and flash system works, especially metering and shutter speed. A good reading is on photonotes.org as mentioned below, it's also labeled "Flash Bible". Different camera systems have different ways of doing things for reasons we can only guess about. Learn how to use it
    Last edited by Octarine; 16th May 2010 at 01:17 PM.
    EOS

  15. #15

    Default Re: why canon shutter speed does not change with flash????

    Quote Originally Posted by teck21 View Post
    Hi all,
    Having a canon 450d but whenever i shoot in AV mode, there is no different on the shutter speed regardless my flash is mount or not mount onto the body... Is this the correct way canon body works or isn't some malfunction on my canon body or flash or isn't i miss our some setting??? BTW i am having the same issue using build-in flash....

    The external flash i using is canon 430exII


    Pls help

    Thanks!!!
    Quote Originally Posted by teck21 View Post
    thanks everyone for the reply
    cos i find it quite weird that when AV mode is selected, shuttle speed is only be fixed to 1/200(in custom function). I tried using nikon demo system before and if i remember correct, when av mode is selected shuttle speed will change according if flash (build-in) is pop up hence if flash is pop up, shuttle speed will be faster and if flash is de-activated

    shuttle speed will be slower.
    Check your manual for Cfn controls.

    It's not weird; it's an option which allows the EOS flash system to behave 'like a conventional flash system', albeit in a limited manner.

    The document provided by Edwin Francis reveals that EOS flash system was designed to think and behave in a very different manner from conventional flash systems.

  16. #16

    Default Re: why canon shutter speed does not change with flash????

    Quote Originally Posted by teck21 View Post
    Hi all,
    Having a canon 450d but whenever i shoot in AV mode, there is no different on the shutter speed regardless my flash is mount or not mount onto the body... Is this the correct way canon body works or isn't some malfunction on my canon body or flash or isn't i miss our some setting??? BTW i am having the same issue using build-in flash....

    The external flash i using is canon 430exII


    Pls help

    Thanks!!!
    I got the same "problem" also. :> Thanks to clubsnap and all the members, I got my answer.

    Thanks all!
    Canon , Pansonic
    flickr

  17. #17

    Default Re: why canon shutter speed does not change with flash????

    Same topic has been discussed here. Read up if need more info.

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