Nikon D300 and SB600 Flash question

Discussion in 'Nikon' started by brad_richardson|1, May 9, 2015.

  1. Please help me with an explanation of the metering I'm seeing. I have attached two photos to assist with my query (they are phone photos). Using a D300 and SB600 flash in iTTL BL (balanced flash) in P mode I see the exposure meter shows an arrow which is never usually there and I have not been able to find an explanation for it. The shots are way under exposed. Then I change to M mode and and increase the exposure and the bar backs off a little and the shots are improved. I think I have something wrong here. ISO set at 400 with matrix metering. What is this arrow/bar? Why does it appear when flash attached? what is it telling me? Thank you.
  2. Attachment 2
  3. If you mean the +/- symbol with the flash (lightning) icon next to it, it means you have flash compensation dialed in; you can set this using the flash button on the camera together with the rear wheel on the camera. Given you get underexposure, it will be a negative value (so the flash output is lower).
    It is essentially the same as expsoure compensation, so that also explains why in manual mode you can 'override' it (that is, adjust expsosure to a level where the lower flash output balances correctly with your exposure settings).
    The larger bar below that shows exposure; if it is to the left: underexposure, to the right, overexposure (on your display +3EV to -3EV). It is quite common to show underexposure while using flash, as the bar shows the reading of the lightmeter versus your exposure settings without taking the flash in consideration - essentially iTTL is expected to "fill the gap".
  4. "if it is to the left: underexposure, to the right, overexposure"
    The direction depends on menu settings. Better would have been: if towards the '+' sign (on the left in the photo of the display), overexposure, if towards the '-' sign, underexposure.
  5. I am not referring to the + / -. I am referring to the arrow that appears above the 5.6. In the two photos, this bar is a different size - what is this bar - why is it there - what is its purpose and why is it only there when flash is used? I'm concerned that i have a setting wrong because I'm getting under exposed flash photos.
  6. It is your light meter telling you that you are underexposed. You can see it inside the viewfinder as well. In manual mode it changes as you change f/stop or shutter speed, in an auto mode it tells you the same thing. The difference is that you control it completely in Manual. Looking at the second shot you are in Manual and about 2/3 to a full stop underexposed. In the top shot you are more than 2 stops under. In M mode that bar should always be there. In the auto modes I'm not sure as I almost never use them.
    Rick H.
  7. "What is the bar."
    Ditto to what Rick H. said.
    Its the meter bar showing the degree of underexposure. The meter reads the ambient light and does not consider that you're using flash. The settings in the first image (looks like f/7.1 at 1/60) is underexposing an ambient exposure by several stops. The next image (f/3.2 at 1/60), is showing only slightly underexposure, 2/3rds of a stop.
    You should probably be using TTL not TTL-BL in this situation.
  8. The arrow appears when you're more than 3 stops over- or underexposed; it is to indicate it's (literally) off the scale. It is normal to show up when using flash I tried to explain in my previous answer.
    As for the underexposre in your photos: see my previous answer, you do have flash compensation dialed in, so it is not unlikely your flash output is lower than the iTTL systems thinks is needed. Start with setting the flash compensation to zero.
    As Alan said, it is not unlikely you're better off with iTTL than iTTL-BL; the iTTL-BL option sounds a great idea, but it can leave the main subject underexposed in favour of a balanced total, plus if the background is large and/or far away, the flash simply lacks the power. iTTL works far more predictable in my experience.
  9. When you attach and switch on the flash in program mode, the camera automatically changes the shutter speed to 1/60th (by default). The meter, which only measures ambient light will then show underexposure, because it can't measure the flash that's going to be lighting the scene when the shutter is open. Hence you usually get an underexposure indication on the meter when flash is used.
    The little lightning bolt and +/- symbol shows that you also have flash exposure compensation set. You need to look at this. It could be the cause of the flash underexposure. The symbol disappears when flash compensation is set to 0.0.
    And +1 to setting TTL, not TTL-BL when flash is the main or only source of lighting. I-TTL-BL is for when you use the flash as a fill in daylight or for, say, a backlighting situation.
  10. ShunCheung

    ShunCheung Administrator

    Right, as pointed out above, the scale shows over and under-exposure, from +3 stops on the left to -3 on the right. The bar shows the current amount. When the little arrow appears, it means it is beyond 3 stops, off the charts.
    I used to prefer the program mode, as I always felt that I am among the few people who know to take advantage of it. However, by all means avoid P with flash photography. It has a lot of limitations with flash.
  11. The arrow is telling you that because the program mode only allows you to use a certain proscribed range of shutter
    speeds and f-stops that when you use flash, the ambient light portion of the photo will be underexposed by more than
    three stops.

    Program mode is a truly stupid way to work. It gives the camera compete control over the look of your photographs. If you want to automate the exposure aspect it is much better to use Aperture (A) or Shutterspeed (s) modes.
  12. Thank you very much to everyone. You have helped me and I have re read all your responses a couple of times.
    I now understand the way the metering is being displayed. To summarise, in P mode when flash attached, camera automatically sets to 1/60th (minimum) and displays the light deficiency expected to be filled by the flash. From experience, I agree with the criticism of P mode for flash. I note that if the D300 metering is set to centre weighted or matrix the SB600 flash sets itself to iTTL-BL whereas if the metering is set to spot the SB600 sets itself to iTTL. In situation where there is too much difference between dark and light the balanced option fails to light the subject sufficiently. This is why I was getting subject under exposure.
    Better practice is to spot meter on subject using S, A or M mode where flash is necessary to capture an acceptable image of the subject. Balanced fill flash (in P mode) acceptable where rendering of low lights (under the eyes for example) could be improved with use of a little extra artificial light, the difference between available light and the extra lighting required not being that great.
    Please feel free to correct me or let me know off your approach as would really appreciate it. The context is social family photography. Thank you all again.
  13. You don't have to use spot metering to get the SB-600 into iTTL. You can set that on the flash itself with the "Mode" button. Spot metering can be all over the place depending upon the brightness/darkness of the area under the spot. Use Matrix metering, Aperture Priority for an exposure mode, use an appropriate aperture for situation, and put the flash on iTTL. Should work fine for family photography.
  14. Your matrix meter is not the "end all". It makes suggestions. And sometimes, those recommendations are not correct. It is says 1 stop under, it may be, but does not mean that your shot will be. It's a guideline.

Share This Page