Fuji SLR Camera loses 2 stop (or more) sensitivity with prolonged "on-time"

Discussion in 'Fuji' started by Graphic, Jul 12, 2003.

  1. Graphic

    Graphic Guest

    Has anyone else experienced this phenomenon:

    I am a convention photographer and often do on-site portraits with
    studio-type lighting.

    The last 2 times that I used my Fuji S620-Z camera (with sensor chip
    very
    similar to the S-1 from what I understand) I had the camera turned on
    for
    most of 6-hours then most of 10 hours on 2 separate days.

    The first time, the exposures took a sudden nose-dive towards 2-stops
    under-exposed and I blamed my lights since I did not carry my
    falshmeter
    (ok,ok...this is only case where digital has caused me to get lazy
    and want to lighten my camera bag to the max.)

    On the second occassion I brought my light meter plus my back-up
    lights
    that I *always* carry.

    The same thing happened: sudden 2 stop decrease in sensitivity over
    the
    initial flash meter reading of F5.6.

    ONLY this time I pulled out the flash meter--- Still reading F5.6...ok
    shoot some more photos and the histogram shows that the f2.8 photos
    are on
    the button... repeat procedure over the balance of the 200+
    portraits...EXCEPT, now F2.8 is underexposing the last 3 subjects, so
    rather than re-rig the lights I move the stand in closer for perfect
    exposures at F2.8 ...finish up the session and the flash is reading
    1/2
    stop over F5.6 (remember I moved the lights in closer).

    NOTE on the lights: I am using el-cheapo screw in type e.f. that are
    ganged-up 4-lights to a fixture aimed into an umbrella. Not elegant
    but it
    always works as well as the expensive alternative *and* always
    consistently
    with film exposures.

    What this means is that to get a 2-stop loss in speed, the equivalent
    of 3
    out of 4 independent flash units need to fail consistently with the
    Fuji
    digital camera and work perfectly with the flashmeter even when the
    pops
    are intermixed between the two. I think this rules out the e.f. as the
    culprit.

    Any ideas about the true cause and solution?

    TIA
    Wayne Catalano
     
    Graphic, Jul 12, 2003
    #1
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  2. Graphic

    Tony Wallis Guest

    Hi Cliff,

    I see you are using S2's for Wedding Work. Can I ask what flash set up you
    are using? Looking at doing my work in digital at the moment.

    Cheers

    Tony Wallis
     
    Tony Wallis, Jul 18, 2003
    #2
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