Shallow or Deep.

One of the most important thing that turn an ok photograph in to an amazing image is depth of field. In simple terms, how deep is our field. If we are looking at a field, ask yourself the question how much of the field do you want to be in focus? Just the front part, the middle part or all of it?

In the image below we demonstrate using an model aircraft. Look carefully at the various different apertures and you'll see what appears to be in focus and out of focus. This is all controlled by the aperture setting but there are other factors to consider too. The three main factors are :

Distance to subject - You'll get a shallower (more out of focus background) the closer your camera is to the subject.

Focal length : The higher the focal length of your lens the shallower the depth of field. Whilst it is very hard to get a shallow depth of field using a very wide angle lend it's very easy to get one with a longer focal length lens. 

Aperture : The lower the F-Stop the larger the opening in the lens is. A large aperture (such as F2.8) gives a shallow depth of field. 

 

 

Lastly, which very few people mention, your camera sensor size comes in to play. Mobile phones have a tiny sensor and the only way you'll get a shallow depth of field with one of these is to get so so close to the subject. Using the example below you'll see the keyboard has a very shallow depth of field but the mobile phone camera lens was around 5 cm from the keyboard. The second example shows around 15cm from the keyboard and everything is in focus ( a long depth of field).

So to summarise. If you would like to get a nice blurry background ; Don't use a mobile phone unless you are photographing something within 5 cm... Use a digital SLR preferably. Second, practice between stepping away and using a long lens and getting in closer and using a midd range lens. The lens that works best is an 85mm on a full frame camera as it's wide enough to get close to your subject but high enough focal length to get your blurry background. Now set the aperture wide open (low Fstop number) and adjust your shutter speed accordingly.