• If you look at your lens, you can see the opening where light comes through. When you adjust your aperture settings, you’ll see that opening get bigger and smaller.
  • The larger the opening, or wider the aperture, the more light you let in with each exposure. The smaller the opening, or narrower the aperture, the less light you let in.
  • Why would you ever want a narrow aperture if a wider one lets in more light? Aside from those situations where you have too much light and want to let less of it in, narrowing the aperture means more of the photograph will appear to be in focus.
  • For example, a narrow aperture is great for landscapes. A wider aperture means less of the photograph will be in focus, which is something that’s generally visually pleasing and isn’t seen as a downside.
  • If you’ve seen photographs with a subject in focus and beautiful blurred backgrounds, this is often the effect of a wide aperture (although that’s not the only contributing factor—remember, telephoto lenses decrease depth of field as well). Using a wide aperture is generally considered the best method for taking in more light because the downside—less of the photograph being in focus—is often a desired result.
  • Aperture is represented in f-stops. A lower number, like f/1.8, denotes a wider aperture, and a higher number, like f/22, denotes a narrower aperture.

Shutter Speed

  • the specific amount of time to close the aperture when you click shutter button
  • Fast shutter speed: captures more light, helpful in less light situation. But it can capture motion and make blur images
  • So you often want fast shutter speed camera unless you have following circumstances:  Blur the image for artistic purposes  OR, Shooting in low light


  • ISO is the digital equivalent (or approximation) of film speed. If you remember buying film for a regular camera, you’d get 100 or 200 for outdoors and 400 or 800 for indoors.
  • The faster the film speed the more sensitive it is to light. All of this still applies to digital photography, but it’s called an ISO rating instead. But usually it is automated, and not provided in manual settings.
  • The advantage of a low ISO is that the light in a given exposure is more accurately represented.
  • If you’ve seen photos at night, the lights often look like they’re much brighter and bleeding into other areas of the photo. This is the result of a high ISO—a greater sensitivity to light. High ISOs are particularly useful for picking up more detail in a dark photograph without reducing the shutter speed or widening the aperture more than you want to, but it comes at a cost.
  • Disadvantage of high ISO: lights being overly and unrealistically bright in your photos, high ISO settings are the biggest contributors to photographic noise. High-end cameras will pick up less noise at higher ISOs than low-end cameras, but the rule is always the same: the higher you increase your ISO, the more noise you get.


Summary: when manually handing the settings, look for your requirements

  • Do you want to ensure a shallow depth of field? If so, your priority is your aperture.
  • Do you want the most accurate representation of light? Make ISO your priority.
  • Do you want to prevent as much motion blur as possible? Concentrate on shutter speed first.