The goal of a proper exposure is to have the whites be true white, the blacks be true black, and for both areas to show visible details within.
Often times, our exposures don't show all of the subtle nuances that are happening in the highlights or in the shadows. The presence of true detail is what can make the difference between a good photo and a bad photo.
Take a look at the photos below and notice that sometimes the lightest parts of the flower petals (where the sun is hitting them on the left side) are so blown out that if you were to cut away the rest of the image, you'd just have an area of pure blinding white. You'd no longer be able to tell that this area was part of a flower!
Likewise, the bottom right corner of the shot begins to slip into pure blackness as the exposure is lessened. There's no longer any detail left to inform you that you're looking at plant foliage.
ISO 800/ 7.1/ 125 (+4)
ISO 800/ 7.1/ 160 (+3)
ISO 800/ 7.1/ 200 (+2)
ISO 800/ 7.1/ 250 (+1)
ISO 800/ 7.1/ 320 (Automatic*)
ISO 800/ 7.1/ 400 (-1)
ISO 800/ 7.1/ 500 (-2)
ISO 800/ 7.1/ 640 (-3)
ISO 800/ 7.1/ 800 (-4)
*Automatic - the center photo is what the camera selected as the 'correct exposure', using its built-in light meter. You may prefer an under or overexposed version of the image, and may even find it to be more accurate.
Overexposed: too bright. The whites are 'blown out', meaning that there are no detectable details in the whitest parts of the photo. This happens when the camera settings are not taking in as much light as needed for a good exposure.
Underexposed: too dark. There are no detectable details in the shadows, or the darkest parts of the photo. This happens when the camera takes in more light than is needed for a good exposure.
How to change exposure on an iPhone:
Most folks don't realize that the iPhone's camera allows you complete control over your exposure. When you press the shutter (picture-taking button) the camera is automatically choosing the exposure for you - but you don't have to be locked in to that choice. To overwrite the iPhone's exposure selection:
- Tap the live preview screen, just as though you're choosing a point of focus.
- Tap and hold the sunshine icon that appears; this is the exposure control.
- Adjust the exposure by using the slider that appears.
Getting Good Exposures the Easy Way
Using the photo examples above, you can probably see how it would be helpful to shoot slightly underexposed and slightly overexposed versions of the image, using the camera's automatic settings as a starting point.
This is called bracketing. The good news is that most cameras, both point & shoot and DSLR, have a specialized tool that will do this for you. Most phones also have an HDR setting that will bracket your photos for you and compress them together seamlessly, stealing the finest-detailed portions of each version.
Bracketing: the practice of taking multiple versions of each shot, including underexposures and overexposures, using the 'correct exposure' settings as your starting point. This creates a safety net, ensuring that one of these shots will have the necessary amount of detail in the darkest and lightest areas of your photo.
Modern cameras have an Exposure Compensation setting that puts bracketing literally at your fingertips. After reading up (in your manual or on the google) about exactly how yourcamera's exposure compensation needs to be set, you should be able to shoot away while operating a simple dial that tells the camera: "Same exposure again please, but this time, add more (or less) light!"
Perfect Garden Photo Light Metering - For Free!
Another favorite tool we have is a free app, called myLightMeter, that turns your phone into a light meter (you can find this in your phone's app store). Normally, your camera (or phone) measures the light that's falling on your subject to create what it thinks is the correct exposure.
While that's all fine and good, there's one potential flaw: you're pointing your camera at your subject instead of at the light that's falling on your subject to take your reading.
What we mean by that, is that the most accurate reading comes from measuring the light exactly as it falls on your subject, which is best done by positioning the meter you're using slightly in front of your flowers, and pointed in the general direction of the light source.
myLightMeter in action! Here, our gardener is able to freely move about to take her exposure reading. She can either manually set her camera to match the suggested exposure values, or she can just check in to see if her camera is delivering accurate information. Not a bad service for free!
As part of our Break-the-Internet Photography Series, we'll definitely be diving deeper into exposure. We'll cover aperture, shutter speed, and ISO, giving you all of the nitty gritty on how and why you should be adjusting these settings to get different (properly exposed) outcomes.