Exposure Questions

Discussion in 'General Technical Discussion' started by gbenic, Oct 4, 2005.

  1. I have a couple of questions. In the D70 manual it states that to use exposure compensation, I cannot be using Matrix Metering. It doesn't state which modes to use. I assume that if I switch to spot or center weighted, I can use exposure compensation in P, S, A, and M, correct?

    Another question concerns the SB-600. When I look at the flashing number on the flash's display (lets say -1.7) it is telling me how underexposed the image is (if I understand the manual correctly). When I adjust my exposure on the flash to +1.7 (using the previous example), my flash display says -2.7! What am I doing wrong?

    Uh, I think maybe I know the answer. If I am using Matrix Metering, it won't work with the flash either, will it?

    If this is the case, should I be using center weight instead of Matrix Metering? I am not a fan of spot metering unless it is a very difficult subject to expose because everything else usually blows out for me.
     
    Last edited by a moderator: Oct 4, 2005
  2. Baywing

    Baywing

    Feb 22, 2005
    CT USA
    I don't have a D70, so can't be sure, but.....you should be able to use exp comp with matrix metering, I do with the D100. You will only need exp comp with A and S. Program and M there is no point to it, by nature of the way they work. If you have dialed in -1.7 on the flash, it does not underexpose the entire shot by 1.7 unless the light from the flash is the only or significant light source. If you are using the flash as fill, only the light from the flash will be under by 1.7, which actually is just about right to take the darkness from the shadows, but still let them be seen in a more natural way. (I use -2 to -2.3). I'm not sure why you get that -2.7 reading. On the D100, you can dial in flash comp with the camera body as well as the flash, maybe you have done that or confused the flash comp on the camera with the exp comp.
    Might be time for Thom's e-book!
     
  3. fks

    fks

    Apr 30, 2005
    sf bay area
    hi greg-

    matrix metering is supposed to analyze the scene and determines the appropriate metering, even for tricky lighting situations. for example, it should expose correctly for a backlit subject. most photographers would use exposure compensation in such a case, and this would throw off the matrix metering. this is probably why nikon recommends against using exposure compensation if you're using matrix metering.

    in real use, matrix metering isn't perfect, and if you think some exposure comp is needed, then go for it. i would recommend switching to center weighted or spot though, if you use exposure compensation. your results will be more stable and repeatable if you pick center weighted or spot metering instead of matrix.

    ricky

     
    Last edited by a moderator: Oct 4, 2005
  4. MontyDog

    MontyDog

    Jan 30, 2005
    #1064 - You have an error in your SQL syntax;
     
  5. Thanks for the replies. Does matrix get confused enough that I should be using center weighted?
     
  6. nfoto

    nfoto Guest

    It's only the end user who gets confused in the end. Matrix metering doesn't really care, and while the system in general works quite well, it certainly needs a helping, corrective hand now and then.

    With D2X, you can fine-tune the matrix metering by changings its zero point. This makes the exposures "slide" up or down an EV scale. Many people, yours truly included, have set the "0" point to -1/6 EV to help avoid blown highlights. This is a global change of scale, and won't influence significantly those tricky situations in which matrix metering, despite its claimed 30.000 record data base, still gets tricked into giving bad exposures.
     
  7. I would disagree somewhat. In M while Baywing is correct that exposure comp does not really effect any thing, it will change how your meter reads. So if you are like me and find that your D70 underexposes a bit you dial in some exposure comp so that when you center up the exposure in M mode you are actually a little overexposed to compensate. Now I can do that just by looking a the meter as well (i.e. expose one bump to the + side), but for me it was more convenient to center up the meter and shoot.
    That said, I must admit that as I get a better sence of exposure I have moved the exposure comp back to 0 and do my exposure compinsation with a change in Appature or Shutter using the meter as a guide and knowledge of what fools it to adjust from there. I guess that means I don't really disagree.... :confused:

    Yes I shoot strickly Manual (or old school :smile: )
     
  8. Thom Hogan says to determine which of the two (flash or camera) you want to adjust the exposure with and then be consistent. If you use both in P mode with matrix metering they will fight against each other.
     
  9. Iliah

    Iliah

    Jan 29, 2005
    nowhere
    For me shifting exposure meter in M mode ("exposure compensation") is quite useful, as I often meter in spot mode off highlights, and need to compensate about +2 1/3 eV. It also works nice with Auto ISO.

    I often use Metz 45 CL-4 flash, shutter 1/15 sec, thyristor mode. This flash is marvel IMHO, having main tilt/swivel head for bounce and an independent separate secondary reflector firing straight Histograms make flash output power adjustments very easy. I start with -1 1/2 compensation on the flash.
     
  10. Thank you for the additional replies. There is quite a bit of knowledge around here. I will digest what was said and try what I can.

    Thanks again.
     
  11. Steve S

    Steve S

    Feb 1, 2005
    SE Florida
     
  12. nfoto

    nfoto Guest

    Nope, this won't influence exposure at all. However, and this might be the cause of your confusion, + or - corrections show up in the metering panel and if you adjust to have a zero-point deviation, then you, not the camera, have effectively affected the final exposure :wink:
     
  13. Steve S

    Steve S

    Feb 1, 2005
    SE Florida
    Bjorn, you're giving me far more credit than I deserve, by stating such lofty statements as: "...if you adjust to have a zero-point deviation...". What does this mean? Thank you
     
  14. nfoto

    nfoto Guest

    Hm. Look into the viewfinder, at the bottom there will be a metering panel (with the camera set to manual metering, M mode). There is a series of dots with some numbers above them (or just + and minus, depending on the camera model). On the left is overexposure, on the right is underexposure, in the middle there is a zero number "0". When you turn on the meter, a sequence of these small dots lights up, going to the left or to the right as the incoming light dictates. Adjust exposure by turning the shutter or the aperture dials, or both, until just the dot below "0" is lit. That is the "correct" exposure according to the meter, and you have centered the exposure on it, thus zero deviation.

    If you set "+" or "-" corrections directly on the camera, and then meter by centering the meter panel to the "0" value, then you in fact have made the camera shift its exposure up or down from its zero point. So you have changed the exposure (the camera didn't do this, it just obeyed its master).

    If this explanation doesn't suffice, I'm lost for the needed insight into, and command of, the English language.
     
  15. MontyDog

    MontyDog

    Jan 30, 2005
    #1064 - You have an error in your SQL syntax;
     
  16. Iliah

    Iliah

    Jan 29, 2005
    nowhere
    Ah Paul! Just followed your advice, page 97. Disappointing explanation :)
     
  17. Steve S

    Steve S

    Feb 1, 2005
    SE Florida
    ok, ok, thanks Bjorn, that was very clearly explained now, and I know exactly what you are talking about. Thank you so much! I always wondered what all those dots meant when I went to Manual mode!
     
  18. MontyDog

    MontyDog

    Jan 30, 2005
    #1064 - You have an error in your SQL syntax;
     
  19. Iliah

    Iliah

    Jan 29, 2005
    nowhere
    Well, Paul. I always thought it is more logical to have it on p.97 - where one would IMHO look first. The page is titled "Exposure Compensation" ~<:)>

    Pages 92 and 93 in my edition do not mention exposure compensation settings at all.
     
  20. marc

    marc Guest

    if the flash says -1.7 after you take the photo, the flash is telling you, that you have underexposed by 1.7 stops.

    try opening aperture and take the same photo again, with out changing the other settings, see what happens then
     
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