This month’s challenge covered using the pre-sets on your camera compared to full auto mode.   The main point of this exercise was to start to try and understand the ‘Triangle Of Light’, which is used to describe the balance needed by the 3 main settings that you would alter to change how light or dark your picture is.  We will be looking at each point individually in more detail in the next few months, but basically the three points of the triangle are:


  1. This works like the pupil in your eye, opening up as wide as it can to let light in in dark places, and narrowing down in bright lights.
  2. The maximum amount that it can open is limited by the lens, and the numbers that you see on lens descriptions are related to this.  For example, my Canon 17 – 55 mm f2.8 lens has a maximum (wide) aperture of 2.8 whether I’m at 17mm or 55mm on the zoom, but my Tamron 70 – 300mm f4 – 5.6 has a maximum (wide) aperture of 4 at the 70mm end, and 5.6 at the 300mm end.  On fixed lens cameras there will also be a range for either end of the zoom, but it may not be so obviously marked – your manual should be able to help.
  3. Due to the way the ‘focal plane’ works, the wider your aperture, the shallower your ‘depth of field’ is – we’ll cover more of this next month, but it relates to how much of your picture is in focus.

Shutter Speed:

  1. This is the speed at which the shutter opens and closes to expose the ‘film’ (in digital terms the screen at the back) to the light coming in from the subject being photographed.
  2. In bright situations this will be measured in small fractions of a second, while in dark situations it can be multiple seconds, which means that in darker situations you may find it hard to hold the camera steadily enough to get a sharp, in focus photo.
  3. The shutter is the ‘clunk click’ sound you hear when you press the button to take the photo, have a listen to see if you can hear the differences in different light situations (you’ll be pleased to know that I’ve heard of cameras simulating the noise too if they don’t work like a DSLR…)


  1. In the old days this was the number you used to get marked on the side of films – 100, 200, 400, 800 and 1600.  In some digital cameras you can actually go even higher than this, but is probably not essential unless you like taking photos in dark caves!
  2. Basically the higher the number, the more it can cope with the dark, so for example you would use ISO 100 on a nice, sunny day, and ISO 1600 in a pub (not that I would ever take photos in a pub…)

We’ll start off by looking at what auto mode actually aims to achieve.

Full Auto Mode

  1. Everything in focus – Fully automatic modes usually use a matrix type system where a number of points are used for focussing.  This may mean that it misses the thing you actually wanted to focus on when you have many objects in the frame.
  2. Everything as well lit as possible – Outside in daylight it will utilise the ambient light, but in darker situations it will probably invoke the built in flash.
  3. It’s about as idiot proof as you can get, but may not render things in a way that you find particularly aesthetically pleasing.

Where the pre-set modes come in is to utilise the Aperture and Shutter Speed in a way that is particularly suited to a subject.

Now my current camera doesn’t have pre-sets, and I couldn’t dig my 20D out from its current hiding place so I went back in time to when I first got the 20D to see what I did then,  I warn you now, the results were not pretty ;o)  Unfortunately I don’t have a comparison with auto for each one, but I can show you what the camera chose to set.

Landscape mode:

Navy Pier, Chicago about 4 days after I’d got the camera!


  1. Focus – This mode aims to have as narrow an aperture as possible to allow for as much of the photo to be in focus as possible.
  2. Shutter speed – This mode will prioritise aperture over shutter speed, but it still won’t allow the shutter speed to get below a level at which the manufacturer’s believe you can’t steadily hand hold the camera any more.
  3. Flash – This mode usually doesn’t use flash, since firing a flash at a large open space will light up only the things that are immediately in front of you.

Settings chosen by the camera:

  1. Aperture – f/16 – this is a narrow aperture setting
  2. Shutter Speed – 1/500 seconds – this is actually pretty fast, but it was a lovely, bright sunny day.
  3. ISO – 320 – this isn’t actually a full stop setting in ISO, I’m not sure why it hasn’t gone down to 100 to be honest
  4. Flash – off
  5. Lens – 18-55mm @ 18mm

Portrait mode:

My friend in Chicago’s son, with another friend and son in the background.  Note that I was having more fun playing with the camera and settings than looking at the composition of the photo!


  1. Focus – This mode aims to have an aperture towards the wider end of the range so that your subject is in focus, but the background isn’t necessarily.
  2. Shutter speed – Again, this mode will prioritise aperture over shutter speed, but it still won’t allow the shutter speed to get below a level at which the manufacturer’s believe you can’t steadily hand hold the camera any more.
  3. Flash – This mode generally does fire the flash if it feels it can’t get the combination of aperture and shutter speed needed to be able to steadily hand hold the camera, since your subject is usually close enough to the camera for the flash to light them up.

Settings chosen by the camera:

  1. Aperture – f/5 – this is quite a wide aperture, so Ben is in focus, but David and Karen (holding him) are rather fuzzier in the background
  2. Shutter Speed – 1/60 seconds – this is as low as the camera thought I could hold
  3. ISO – 400
  4. Flash – on – you can see the catchlights in Ben’s eyes
  5. Lens – 18-55mm @ 41mm

Sports mode:

Rowing was my sport for years, and I took this while umpiring at a local race on the Clyde:


  1. Shutter speed – This is king in sports mode, as the camera tries to freeze the action with as high a shutter speed as possible given the available light
  2. Focus – This mode will prioritise shutter speed over aperture, and the focus point should try and track the moving object if possible between the point that you focus and the point that you fully press the shutter button.
  3. Flash – This mode can fire the flash if it feels it can’t get the combination of aperture and shutter speed needed to be able to steadily hand hold the camera.

Settings chosen by the camera:

  1. Aperture – f/5.6 – this is actually quite wide, but would be needed to get a good, fast shutter speed given how gloomy the day was
  2. Shutter Speed – 1/400 seconds – this is quite fast, albeit rowing boats don’t go that fast, but you can see the individual droplets flying up as the blades went into the water.
  3. ISO – 400
  4. Flash – off – they were far too far away for a flash to have lit anything up (about 350m or so)
  5. Lens – 70-300mm @ 271mm

P for Professional

There is a setting that many cameras have, which is ‘P’, or Programme Mode.  One of my friends (himself a professional photographer) calls this mode ‘P for Professional’ with tongue firmly in cheek, as he has found fellow ‘Pros’ who only used this mode, but think of it as a kind of ‘full auto mode ++’.  In this mode you can usually override full auto for the following:

  1. Set your ISO
  2. Choose to over or under expose your images
  3. Turn your flash off
  4. Alter your flash power

Here is one of the earliest ‘P’ photos I could find, taken on safari in South Africa.  P was chosen to turn off the flash because, well, flashing lions isn’t generally a good idea ;o)

Settings chosen by the camera:

  1. Aperture – f/7.1 – this is about as middle of the range as the camera could get with the available light
  2. Shutter Speed – 1/320 seconds
  3. ISO – 800 – this was chosen deliberately as being about as high as you could get without super grainy photos
  4. Flash – off – lion, remember?
  5. Lens – 70-300mm @ 100mm

To see what settings your camera has chosen, you need to check the ‘EXIF’ data of the file, so if you are in Windows Explorer, for example, you should be able to single click on an image, or even hover over it to see the information.  You should at the very least be able to see the aperture, shutter speed and ISO, but may also be able to see things such as the focal length of the lens when you took the photo and the focal range of your lens.  EXIF data can also be viewed in Photoshop (full and Elements) or on a Mac in iPhoto, as well as in many other bits of software.

Take a look at the EXIF data for your challenge photos to see what options your camera chose for you in both the pre-set modes and auto mode.

Now link up what you’ve been taking photos of during the challenge: