Aperture, Shutter speed and ISO

Getting the settings right in camera is the first step to creating a great image. Some people think ‘oh I’ll fix it later in Photoshop’ but usually it is either more time consuming, or looks fake. It’s always a lot better to get it right in camera in the first place, then you can enhance the shot in post production.


This is where you set how much of the shot will be in focus.
It can be a little bit backwards at first to try and get your head around it, as a smaller f number means the aperture is opened wider…

If you are working with a kit lens then the chances are your lens goes from f4 to f22 (or similar).
f4 means that the lens will let in a lot more light, but less of the shot will be in perfect focus. More light in means that you are more likely to be able to hand hold your shot.
f22 means that the lens will let in less light, but more of the shot will be in perfect focus. Less light in means that you will probably need to use a tripod to shoot your shot.


Aperture: f1.8 – The leaf is mostly in focus but not all of it is. The foreground and background are not in focus at all.
Sheffield in Autumn // 11 10 14

Aperture: f14 – Most of the shot is in focus, from the rocks to in the foreground to the waterfall in the background
Lumsdale Waterfall

Shutter speed

This is how quickly your shutter will be open for. The longer is is open for the more light will be let in, however the longer you leave it open for the more likely you will need to put the camera on a tripod (Unless you have really steady hands!)

A shutter speed of 1/500 will freeze motion, where as a shutter speed of 2″ (2 seconds) will capture some motion, which in camera will look blurry.


Shutter: 1/250 – The water and clouds are frozen in place.
Sant'Agnello // 15 08 14

Shutter speed: 0.6″ – The unmoving aspects of the shot (the flower pot and Danbo) are frozen in place, but the flowers which were moving in the wind are blurry
Hold On! // 23 02 12


ISO is  a bit more abstract to talk about, and much harder to show how it looks in my images!
The lower your ISO number the cleaner your shot will be, the higher your ISO number the more grain will be in it. It is for a lot of people the hardest of the three to understand because it can be difficult to see how it works. Ideally you need to keep your ISO as low as possible, because having grain in your image is seen as being undesirable.

So why would you want to turn your ISO up?
The higher your ISO the quicker the camera records the image, so if you are somewhere dark and you are having to hand hold your shot a higher ISO would be beneficial as you are more likely to not get any camera shake and have an image which looks more in focus. In an ideal situation you would want to keep your ISO lower, and put your camera on a tripod however that is not always possible (at a gig or concert, some places such as caves don’t allow you to set up a tripod when you are on a tour).

You can reduce grain (or noise) in post processing (Lightroom and Photoshop both have options to do this), but it’s not a perfect way of doing it, and you compromise other aspects of the shot by doing so (it might look smoother all over, so you will have a loss of detail).

Combining the three to create your shot

All image makers must choose their aperture, shutter speed and ISO for every shot. Some people (like me) use full manual mode (where you select all three of the options yourself), but most people tend to use aperture priority or shutter prioirty modes.
These modes allow you to choose the aperture, and the camera sets the shutter and ISO (aperture priority), or it allows you to choose the shutter speed, and the camera sets the aperture and ISO (shutter priority).

What’s the best way to learn about these techniques?

Get out there and shoot. Spend a day where you have to shoot in aperture priority. Take the same shot with different aperture sizes and compare them when you get home. Do the same with shutter priority.

4 thoughts on “Aperture, Shutter speed and ISO”

  1. Great explanations! I almost forgot about the tricky thing in the aperture, but it is good to be reminded why others may have difficulties in understanding it 🙂


    1. Thank you 🙂
      I can remember being really confused by the idea that the number got smaller but technically the hole got bigger!
      It’s strange how things become second nature though and we do them without really thinking about it once we have gotten used to it!


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