Photography basics: 1. Exposure

Before discussing topics like post-production and colour correction or PS6 or Adobe lightroom, I should go through the basics in a series of 1-3 or 1-5 posts.

The most important aspect before framing or even correct white balance would be correctly exposing the camera for the environment you’re in and the kind of shot you want to take. Exposure consists of 3 important factors, all which are interconnected, so if one is adjusted the rest are affected in a knock on effect. 3 Factors:

  1. ISO (sensitivity to light)
  2. Aperture (proportion of sensor exposed)
  3. Shutter speed (degree of time the sensor is exposed to light)

Before going into a scenario it’s  important to know that higher aperture (F stop) affects the range in which objects in your image are in focus, higher aperture decreases the proportion of the sensor exposed to light, however will increase the ‘depth of field’ so objects/subjects further away will be in focus. Another thing to know would be that increasing your ISO will cause your image to become ‘noisy’ (grainy) which you don’t want.The_Exposure_Triangle1

Consider these three factors to be in a triangle where you aim to be balanced as close to the centre as possible, let’s assume you’re indoors taking a portrait of someone. You would need a higher ISO as there is limited natural light indoors, this increased sensitivity to light will cause your image to become too light therefore to counter this you can increase your shutter speed as your subject won’t be moving much, by doing this you are limiting the amount of time the sensor is taking in the light of the image so it may become too dark, to balance this and increase the light you can decrease the aperture to increase the proportion of the sensor exposed to light. For a portrait shot your subject won’t be far away, therefore your depth of field doesn’t need to be deep which is why this adjustment can be justified. (note low aperture will also blur out the background and only keep the subject in focus which is a good sign of flare in portrait photography).

Notice how I used the type of shot I planned on taking and the environment I was taking it in to make judgements on the adjustments necessary to correctly expose the picture. For those of you still learning how to get this right, you would rather have a shot that’s too dark (underexposed) as it can be salvaged in Adobe lightroom, whereas a shot that’s too light (overexposed) can’t be.

Here are some examples to provide some context to exposure. These were just taken on my phone’s rear facing camera as an example.

Under exposed                Well exposed                  Over exposed


Feel free to comment any questions or address anything that wasn’t clear 🙂



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