Depth of Field

1. *Depth of Field*

In this exercise we explored the differences between the eye and the camera in terms of each one’s depth perception, or how they each “see” in a three dimensional world. I identified three main ways to judge depth perception in a photograph: the scale (far away things are very small), background (notable difference between detail in fore and backgrounds) and detail (closer objects are more detailed). With this in mind we set about trying to identify which features of the camera determine the depth of field of a picture. We named three main factors affecting depth of field: the aperture, the distance from the subject, and the type of lens used. The size of the aperture opening determines the depth of field in an inverse relationship, with a large aperture (of say f.2) giving a small depth of field and a small aperture (f.22) giving a very large depth of field. Thus F.22 is ideal for landscapes and mountain ranges, f.8- f.10 are good for objects 5 to 10 metres away and f.4.5 is ideally used for close up images requiring minimal depth of field. Another simple rule I picked up was that the closer you are to the subject you are focussing on, the more out of focus everything else will be, in other words you end up with a very small depth of field. Conversely, the further away you are form the subject of focus the greater depth of field you will be able to achieve. The third factor, the type of lens used, has to do with the way light is curved through the camera with various lenses, with an 18mm lens producing a very high depth of field while a longer 55mm lens produces an image with a very out of focus background and thus low depth of field.

What I learnt from all of this was various ways to control what is being said in my pictures with the knowledge that I have manoeuvring space within my configuration of settings to accommodate different photographic situations. For example if I am in a low light situation and need as large an aperture opening as I can get to capture the image, I can still manipulate my depth of field using my lens or distance away from the subject, thus I can achieve my desired result without having to compromise
depth of field for good light.












Blessed