What is lens aperture (f-stop)?: try it yourself

This is the practical for the lesson. Work through it in order. Nothing here is a test of memory. Keep the lesson open if you need it and check the instructions as often as you like.

Aim

You should be able to point to the photographs and explain what changed. If the depth-of-field difference is weak, move closer to the front object and increase the distance between it and the background.

What you need

Your own camera or phone, enough battery power to complete the exercise, and a memory card or free storage space where your equipment requires it. You do not need to buy anything specially for this practical.

Do this step by step

1. Arrange three objects at different distances from the camera.
2. Use Aperture Priority and focus on the nearest object.
3. Choose the lowest f-number your lens allows and take a photograph.
4. Without moving the camera or objects, take another at f/8.
5. Try f/16 if available and if there is enough light, preferably with the camera supported.
6. Compare the background and also note the shutter speed the camera chose for each photograph.

What should happen

You should be able to point to the photographs and explain what changed. If the depth-of-field difference is weak, move closer to the front object and increase the distance between it and the background.

If it does not work

Stop rather than changing lots of things at once. Check that the camera is switched on, the battery has charge and the card or storage is available. Then return to the last step that definitely worked. If a named control is missing, your camera may use a different name or menu location. Check the manual for your exact model. Never force a card, battery, lens, door or control.

Before you finish

Explain out loud, or in one sentence on paper, what you changed and what happened. If you can explain the result in your own words, you have understood the exercise. If you cannot, repeat the part that was unclear.