Monday, February 8, 2016

Photojournalism students learn ISOs, shutters speeds and f/stops...oh my!

Wayne State's COM 2280 Digital Photojournalism class pose after practicing with motion. (Photos by Lori King)
    Photography is easy. Just put your camera mode on Auto or Program and shoot. The camera will think for you!
    But we don't do things the easy way. My photojournalism and multimedia students are required to shoot on Manual mode, giving them full control of the camera, and their images. And this ain't easy. It's expected they will make lots of mistakes. After all, isn't that how we learn?
  • This is a recap, in a nutshell, of what was learned this past week:                              The camera is an instrument that controls light. It doesn't know what the subject is that it's capturing, whether that be a human, building or pet.
  • The camera is built to read light that bounces off of 18% gray tones. White or bright objects will reflect too much light, while black or dark objects will absorb the light; hence light bouncing off of gray is the magic tone for correct exposure.
  • The three controls that take away or add light are ISO, shutter speed and aperture (f/stop).
    - ISO is one way to control light, and you should always set that first. It is the camera sensor's sensitivity to light. The higher the ISO, the more light you add to the scene, or the lower the ISO, the less light you add.
    These are the standard ISOs: 200, 400, 800, 1600, 3200, 6400. ISO 400 is a good middle ground, but it is on the slow side. We refer to ISOs as slow or fast speed. A 200 ISO is slow, and a 1600 ISO is fast. Because 1600 adds more light to the sensor, you can set a fast shutter speed, which takes away light. Simple formula: The faster the ISO, the faster the shutter speed.
    - Shutter speed is when you trigger the shutter button and a mirror (for cameras with mirrors) opens and closes. All you need to know is that the longer the mirror stays open, the more light hits the sensor. The faster the mirror opens and closes, the less light hits the sensor.
    The shutter speed has another job, as well: motion. The three types of motion are blur, panned and stopped. Blur and panned are best accomplished at around 1/30th of a second. While stopped action is best shot at 1/500th of a second and faster.
    These are the standard shutter speeds: 1/30, 1/60, 1/125, 1/250, 1/500, 1/1000, 1/2000, 1/4000.
    - Apertures, also called f/stops, are controlled through the lens.
    These are the standard f/stops: f2.8, f4, f5.6, f8, f11, f16, f22, f32.
    When you set your aperture, you're opening or closing a hole in the lens. F2.8 is the biggest hole, allowing in more light, while f32 is the smallest, allowing in very little light. This concept can be confusing because the smaller number is the bigger hole. Just remember that these numbers are actually fractions that measure the diameter of the hole. So, f/4 is actually 1/4th, and F/8 is actually 1/8th: 1/4th is twice as big as 1/8th. Yes, there's math involved!
         Aperture also has another job. It controls depth of field. A shallow depth of field (subject in focus while foreground and background is out of focus) is at the f2.8 range, while a wide depth of field (subject and fore/background is in focus) is around f/16 and smaller.
    These three controls work together to add or take away light. This is called reciprocity, as they are reciprocal to one another.
    Photographically, we measure light in stops. The setting between ISO 400 and 800 is one stop, which is the exact same amount of light as between f/4 and f5.6, which is the same amount as between 1/125th of a second and 1/250th.
   So, to meter properly, set the ISO first; then set your either your aperture or shutter speed, depending on the depth of field or motion you want to achieve; meter on a gray tone; and then set the third control accordingly. It's very important you pay attention to your inside camera meter, because it is your measuring cup, so to speak. Once you meter on the gray tone, then you can shoot your subject (and ignore the meter). 
    See how easy this is? Actually, it's not that easy. But once you comprehend the numbers game, it actually makes sense.
    Keep in mind that this might all sound very confusing, but we talked about this lesson during class. So, I hope it makes sense to them.
    I could go on and on, but after a while the numbers get all jumbled, so I'll stop here and let it all soak in. 
    (Sometime soon: lenses and white balance, and whatever else we talked about.)
Students prepare to capture me running back and forth for a panning exercise, and doing jump jacks to stop and blur motion.

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