Nikon F100 + SB800 flash help

Discussion in 'Nikon' started by josephlockley1, Feb 12, 2021.

  1. Hey guys,

    I shoot my F100 all the time and really love it. I just got an SB800 flash for it and I'm a little confused about the modes and how everything works.

    I've got the SB800 on TTL + BL mode and the F100 is in aperture priority mode. I'm confused as to why the F100 isn't suggesting 1/250 (max sync shutter speed), but instead metering and selecting shutter speeds as if there's no flash on it. Do I have to control the shutter speed myself?

    Another question is regarding the flash distance on the SB800 screen. As I make my aperture wider and let more light into the lens, the flash seems to become stronger and go much further. Why is this?

    Sorry for the questions, I'm pretty new to flash photography.

  2. Everything is working as it should.

    The BL in TTL + BL stands for Balanced, meaning the camera tries to expose for both the main subject and the background. Since the SB800 probably cannot evenly light the background the camera tries to expose for it, hence the slow shutter speed.

    As the SB800 manual describes it, "In this mode, the camera automatically controls the flash output to keep both the subject and background properly exposed."

    and the SB800 Shooting Guide states, "Automatic Balanced Fill-Flash The flash output level is automatically adjusted for a well-balanced exposure of the main subject and background."

    In other words it is trying to keep everything balance which is what you selected. Try selecting just TTL or go to manual and select both shutter speed and aperture; the flash will try to provide the required light.

    As for the flash distance question, the flash can provide only so much light. As you close the aperture you are cutting out some of that light. The smaller the aperture the less light you admit to the camera; the wider the aperture the more light you admit. Light from a point source (the SB800) falls off as the square of distance. As you open the aperture you admit more light so the light reflected from more distant objects is sufficient to expose the film and the distance at which the SB800 can provide the light increases.

    You have a great flash. I like mine on both my F100 and D750.

    By the way, if you have a digital camera, experiment with the SB800 on it. It is much more economical to experiment with digital than film and you see the results immediately. The principles remain the same. Just select a fixed ISO for the digital camera.
  3. Amazing explanation, cheers man!
    bgelfand likes this.
  4. You must have the camera set to slow sync. With factory default it would set the shutter speed to 1/60 in A mode if the ambient light is low. It only set the shutter speed higher than 1/60 up to 1/250 if the ambient light is sufficient for correct exposure at those speeds.

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