Questions from a confused flash user

Discussion in '35mm Cameras' started by Ron Glos, Nov 11, 2004.

  1. Ron Glos

    Ron Glos Guest


    I have scoured my instruction books but can't seem to get clear
    explanations to a couple of questions I have. I'm not sure how
    much the particular equipment matters, but I'm using a Nikon F5
    and SB-28 flash.

    I have set the flash to TTL multi-sensor and the camera to
    aperture mode. If I turn on the camera and press the shutter
    halfway, I notice a particular shutter speed. If I then turn on
    the flash, I notice that the shutter speed doesn't change. I'm
    guessing that the camera is picking a different shutter speed
    when the shutter is fully depressed. If so, how can I tell what
    value was actually used? Is it always the sync speed (250), or
    simply some value up to 250? Is there a way that I can force it
    to be 250 if I want to attempt to freeze subject movement?

    The next batch of confusion revolves around the set-up mentioned
    above, but with the camera in manual mode. If I set an aperture
    and shutter speed and the flash is turned on, does the camera
    honor the specified shutter speed, or does it pick one in concert
    with the flash? If so, again, what value does it pick? If not,
    is the flash really doing anything in this case and how would it
    know how much output to fire?

    Thanks in advance,

    Ron Glos, Nov 11, 2004
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  2. I don't do a lot of flash photography but IIRC the F5 normally sets itself
    to 1/60 with the flash attached and turned on. In aperture priority mode it
    will stay at this number unless there is more light than would be correct
    for exposure at that aperture and shutter speed in which case it will start
    moving the shutter speed up until it reaches 1/250 at which point it goes
    tilt :)

    In manual mode it gets mad at you if you set the shutter higher than 1/250
    but if you're at or slower than that speed the camera will maintain the
    settings you chose and adjust the flash power accordingly.

    The variable you're leaving out is that the F5/SB28 can control exposure
    with aperture, shutter speed AND flash power so if you have one of those
    variables locked in the exposure will be controlled by adjusting one or both
    of the others.

    Jeffery S. Harrison
    Jeffery Harrison, Nov 11, 2004
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  3. Ron Glos

    DALLAS Guest

    As Jeffrey suggested, the F5 (or any Nikon with TTL flash) will usually
    select a shutter speed somewhere below its maximum synch speed and adjust
    the power of the flash to achieve correct exposure if you are using matrix

    If you are looking to freeze action with a flashgun, use S mode and select
    something close to the max synch speed. The camera will probably select
    the maximum aperture of your lens which may or may not be what you are
    after. Therefore...manual mode is your friend with TTL flash because the
    aperture and shutter remain as whatever you set them to and the flash
    varies to provide the correct exposure.
    DALLAS, Nov 11, 2004
  4. Ron Glos

    Ron Glos Guest

    Thanks for the great info!
    Ron Glos, Nov 11, 2004
  5. Ron Glos

    Alan Browne Guest

    It uses 1/250. Which might not be what you want at all.

    Flash duration is on the order of 1/10,000 to 1/1000 of a second, any shutter
    speed will work to record the flash exposure up to the max sync speed of the
    camera (in 35mm cameras the top shutter speed is 1/300, with a couple
    exceptions). A slower shutter speed will allow more ambient light to record on
    the film as well.

    It is a mystery how my camera (Maxxum 9), in A-pri TTL flash, chooses the
    shutter speed, it is rarely max synch. So I shoot almost all flash photography
    in Manual mode with the shutter speed appropriate to the ambient I may catch v.
    motion control (camera or ambient lighted motion).
    As stated above, the duration of the flash light is much shorter than the
    fastest sync speed of the F5.

    A flash exposure is almost always a double exposure. One exposure for ambient,
    one exposure for flash. (almost? Yes, there are cases where there is no
    ambient light to be recorded at the chosen shutter speed).

    If, for example, you want the Christmas tree lights included in the shot, set
    the aperture as you want it, then spot meter a white bulb on the tree as closely
    as you can manage. Whatever speed you get, slow it by 2 stops (1/30 becomes
    1/8; 1 sec becomes 4 sec...). Set that speed. Put the camera on a tripod. Say
    the speed is 4 seconds. When you fire the shutter, you get one exposure by
    flash of the subject and then the second exposure (X-mas tree lights) takes 4
    seconds to expose onto the film.

    The details of how your particular camera and flash set speeds are probably
    buried seep in the F5 manual and/or flash manual. RTFM.

    Hope that helps.
    Alan Browne, Nov 11, 2004
  6. Ron Glos

    Alan Browne Guest

    blush ---> top _sync_ speed.
    Alan Browne, Nov 11, 2004
  7. Ron Glos

    John Honan Guest

    I thought 1/125 was the norm for top sync speed?

    Anyway, to follow up on this thread rather than start a new one. What is
    the rule for fill flash? - Do you work out exposure as if for 'available
    light' and pretend the fill flash wasn't even there, or do you have to
    compensate for it somehow?

    For example, outdoor portraiture with fill flash on a fully manual
    setup. Do you use a light meter, a flash meter, or some other way of
    calculating settings?
    John Honan, Nov 12, 2004
  8. Ron Glos

    Alan Browne Guest

    There is no "norm" other than perhaps the "B" setting. Hold open the shutter,
    fire the flash, close the shutter. 1/60 was quite common for a long time, then
    1/125 was pretty common ...blah blah, 1/200... etc. now top end SLR's do 1/250
    to 1/300. There are also a few leaf shuttered lenses for 35mm that do 1/500 and
    Gordon Moat will leap in and say he has a leaf that does 1/1000 (Rollei MF
    camera). Many MF lenses are leaf shuttered with 1/500 being a very common sync
    speed for those lenses.

    The requirement for sync is only that the first curtain be completely out of the
    way before the flash fires and that it has a dwell time before the 2d curtain
    closes that is at least 1/1000 (1ms) long (1/500 is better (2ms)). Flashes at
    medium/low power are all done in 1/10,000 to 1/5000 of a second... at full power
    they emit for about 2ms (1/500).

    Very Basic: set the flash for 1 stop less light than the ambient. Example, you
    want to shoot a subject at f/8. Set your flash power so that the flash incident
    reading is f/5.6. Set the lens at f/8. Set the shutter speed for a correct
    ambient exposure at f/8 (incident meter reading). The ambient lighting will
    record normally, the flash fill will be 1 stop under that... (pretty strong
    fill). From there try setting the flash power lower (reading of f/4 v. the
    aperture at f/8). This can all get stated as ratios and I screw it up all the
    time, so I simply think in terms of how many stops below ambient that I'm
    placing the fill flash... the idea is to not blow away shaddows, just to bring
    them up somewhere in the recording range of the film.

    When I'm rushed I use the AEL mode of the camera which is a "slow sync" to allow
    bacground ambient fill over the flash shot. Work right about 7 times out of 10.

    Alan Browne, Nov 12, 2004
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