Exercise: Focus at different apertures

Three elements affect how an image is made: Aperture/Shutter Speed/ISO (to be discussed in depth @ [xx])

The object of this exercise is to show how focusing at different apertures effects the sharpness of the subject matter and to illustrate the depth of field achieved. Using manual settings I took three photographs, one at the widest aperture, one at the mid-point and one at the smallest aperture. As recommended, I choose to shoot something on an angle, and decided on a row of cans. (inspired by Andy Warhol’s Campbell's Soup).

[f4 1/60 ISO 1250]

Here the sharpest point of focus is on the second tin from the back, the third and fourth cans beginning to be out of focus.  – This image exhibits depth of field.

[f9 1/40 ISO 1250]

I chose an aperture of f9 for the second image being the mid point in my lens range. Here the range of sharpness of image is spreading slightly from the second can to include some of the rear can. The front can, remains out of focus, and there is still a certain amount of depth of field

[f22 1/4 ISO 1250]

In the final shot, I used the smallest aperture f22. When the image is enlarged, you can see that most of the cans appear in focus and are sharper.

In conclusion this exercise demonstrates how, when using the widest aperture, a shallow depth of field is achieved, along with a smaller area of sharp focus. In contrast, the smallest aperture captures more of the image and increases the clarity and sharpness.

Exercise: focus with a set aperture:

 Focus with a set aperture:

This exercise required me to shoot a scene using my lowest f-stop number (f4) and to take three photographs, each focusing on something at a different distance.

I set my camera on my tripod, and the aperture @ f4, and manually focused in on the statue in the foreground. In the middle of the frame, you will notice another small statue of a rabbit, and behind this a tree. Both of these remain out of focus.

In this shot, using the exact same settings I focused in on the small rabbit statue. When this image is enlarged, it is slightly easier to view, and you can see the blurr of the statue in the foreground. However, I think the statue in the foreground is quite overbearing and distracts my attention from what is in focus. On reflection, I should have balanced or framed the scene a bit better.

In the final shot, the tree (or the trunk) appears sharper – with the mid and foreground statues out of focus. In every image though, the statue in the foreground is the dominant feature.I think I will revisit this exercise with another layout.

In conclusion, the lesson has highlighted the concept of depth of field in the photo – for eg. by focusing on the statue in the foreground, the mid and background are blurred, I think this is more interesting and the viewer is drawn into the photograph.

 

PART ONE Introduction: Getting Started

Introduction

My course materials arrived last week, and I have been busy, deciding on the form of blog to use. It is quite encouraging to hear from other students on the OCA forums and going forward I hope to make full use of the facilities available.

The first project is aimed at “getting to know your camera”. I have just changed from Nikon to Canon - so this is a perfect time for me to get to grips with the manual for my camera.

The initial exercises encourage the photographer to become familiar with the camera’s optical system and highlight the differences in the focal length of the lens and differences in the size of the apertures.

Focal length and angle of view:

The aim of this exercise is to help you understand focal length and the distance the reproduced image had to be held from the eye, in order to appear the same size as the subject. The requirements were to shoot a scene, keeping both eyes open with one eye looking through the viewfinder/the other at the scene. I used a Canon 24-105mm zoom lens for this exercise. My first shot was at the standard focal length of 50mm. The second shot, was with the lens at 24mm, ie, at its widest view. Finally, I set the focal length to its furthest telephoto setting of 105mm.

At 50mm the scooter was more or less the same as seen through the viewfinder and with one eye open. When I printed the photo out and held the print up, the distance was 40cm from my eye.

At 24mm the scooter appeared a lot smaller in the viewfinder and further away from what it appeared with my other eye. To achieve an equal view through both eyes, I had to hold the print at 31cm away from my eye. 

Finally, at 105mm the scooter appeared much larger through the viewfinder than with my natural eye. With assistance I managed to view the print at a distance of 90cm from my eye.

In conculsion - this exercise demonstrates the effect of the focal length of the lens, with the aperture at the same setting. I found this interesting, as it forced me to concentrate on the focal length of my lens. As a rule, I try to shoot in manual, but I am I am quite often preoccupied with aperture and speed settings so I found this a useful reflection.