learning exposure ....

Discussion in 'Beginner Questions' started by jason_inskeep, Nov 18, 2008.

  1. so i have recently tried some of some of the "tricks" out of brian peterson's "understanding exposure" book. some of
    them seem to work well others i am not really that sure about. for instance metering all the time on the blue sky
    opposite the sun may work in say colorado but in florida you usually have to add a bit of exposure compensation to
    make every thing right.
    two things that have been really bothering me are...
    when i shoot film my camera only adjusts in 1/2 stops. his technique requires 1/3 stop adjustments. will this really
    make a big difference. when he says to -2/3 ev for green grass i have had good luck withy my digital camera but can
    i expect the same with my film at say -1? since i cant do -2/3
    shooting in situations were you shoot say a flower or something with the sun behind it he says to meter on the flower
    and then move to were the sun would be just visible one the edge of it and shoot for a nice back lit effect. but for
    some reason i am getting shots over exposed buy about a stop. they work in some ways but....
    is this really how you do this....
     
  2. The difference between 1/2 stop and 1/3 stop is only 1/6 stop. It's not a significant difference.
     
  3. Jason
    1/2 f.stop is a fairly slight change in exposure. If you're undecided on whether to open up the aperture or close it down, knowing
    how the film will respond to the change could be helpful. If you're shooting slide film, keep in mind that you don't want to
    overexpose the highlights. Washed out highlights on slide film are not recoverable with any software or printing techniques. If
    you're shooting negatives, it's just the opposite, make sure the shadows aren't underexposed. There is quite a bit of latitude with
    negative film, but it's better to err on the overexposure side.

    In the backlit flower example you suggest, the intent is to make the flower details show, but otherwise keep the flower in shadow.
    With backlighting you want the subject to be slightly dark, but the camera's meter wants to let enough light in to take it out of the
    shadows and make it look well lit. Your meter always wants to make your subject look like it is in normal light. That is, not too dark,
    and not too light, but just right. So to make your exposure slightly dark you need to introduce some brightness into the meter's
    view. That's why Brian Peterson suggests you move the camera/meter to let some sunshine into the view, to balance the
    otherwise too dark of a scene with some brightness. If you let too much sun in, the meter will tell you to stop down too much, and
    the flower will be too dark. If you don't let any sun in, the meter thinks the backlit scene is too dark and it tells you to open up the
    aperture to let some light in.

    So what you did, was to not let enough sun in on the edge of the flower and the meter still presumed it was too dark to get a good
    exposure.

    Your meter doesn't know what you're shooting. It just wants your subject to be right in between pure black, and pure white. It
    thinks everything falls exactly half way in between. If you're shooting a dark scene, your meter will tell you to lighten it up. If you're
    shooting a bright scene, your meter will tell you to stop down.

    It will be helpful to you if you read a bit on the zone system. Even if you don't do any B&W developing or printing, the zone system
    is a good way to wrap your head around how your meter works, and getting good exposures with both film and digital.

    Peter
     
  4. It sounds to me like you are doing exactly what it takes -- doing the research on ways of doing and then seeing how they work in the real world. You've already learned that to slavishly copy someone's technique is not always helpful.
    One of the great benefits of digital photography is relatively "instant" feedback. Chimping is the term used to describe inordinate attention to the LCD screen, but it is a very good way to learn. Although the LCD on the back of the camera is not a perfect representation of what the picture would look like on a monitor or in a print, it (especially if you learn to use the histogram display if your camera has one).
    In short, shoot, shoot some more, and keep track of what you are doing and what works, and you'll soon be able to write your own book on exposure.
     
  5. thank you all for your help. i had thought a bit about the idea of the meter fooling me a bit by giving me too much exposure for the the subject. it was just finding a good balance and how to do it consistantly, in his book he says to get close to the subject and take a meter reading from it then recompose so that the sun just barely shines over an edge of the subject so that you will not get the silhouette but get a starbust kind of effect ( well depending on aperture being wide open or stoped down a bit ) but the idea is to catch a hint of sunlight shining thru a semi translucent object... the way i understand it any way. but i am gettting realatively over exposed reading just following the instructions. they still seem to work in some ways, usually if i bring up the blacks and contrast in photo shop they seem to get me were i want.
    00RXAA-89791584.jpg
     
  6. this next one is one taken with the indicated exposure from metering on a leaf of the same color. it has been adjusted in photoshop add a bit of blacks and contrast.
    00RXAL-89793584.jpg
     
  7. well i tried to post some examples of what i was trying on here but aparently they didn't take. thank you to every one who contributed. so if i am to read Peters response correctly for the situation i had explained with the backlit stuff i shoult just expose for the subject as is with a little light creeping over the side and not for just the subject filling the view finder. thank you. jason
    00RXAc-89797684.jpg
     
  8. i am not seeming to be able to get any submissions to go through.
    thank you though
     
  9. Welcome to the world of half-stops and 3rd stops.

    You *can* adjust in 1/3rd stops if you're using the camera in an automatic or semi-automatic (shutter or aperture preferred) mode. What you do is manually change the ISO up and down. ISO is incremented in 1/3rd stop increments (i.e. 100, 125, 160, 200, 250, 320, 400, 500, 640, 800). But for full-manual work, you're limited to whatever your shutter and lens stops are. And I agree with the above comments: the difference between 1/2 stop increments and 1/3rd stops aren't that big a deal unless you're doing precision work, which is typically done in a studio or places where you can control the lighting.

    Judging exposure comes from experience. It's frustrating but you'll get the hang of it. Like a lot of things in photography, the more you do it, the better you get. I amaze my non-photographer friends because I can compose and focus very quickly; but it's the payoff for a lot of time spent doing it, and a lot of failures getting there.
     
  10. James G. Dainis

    James G. Dainis Moderator

    With negative film, 1/2 or even 1 stop isn't much. Many photographers routinely set their 800 ISO film at 640 ISO and 400 ISO film at 320 ISO. For a test , bracket the same scene at normal, +1/2, and +1 stops and see how different the prints you get from a lab are. They will most likely look identical. The printer analyzer will adjust the extra exposure back so they all look the same although you can see the difference on the negatives.

    If you have the lab develop only and scan the film you will be okay. But don't judge your exposures by prints that you get back from a lab.
     

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