Advanced Camera Settings - Central Focus Point

For this activity, I experimented with the Central Focus Point on my Canon 550D. This means the camera will focus solely with the central section of the lens.

I used a small owl in good light to take these shots and showed the effects the central focus can have on focusing an image.

IMAGE 1

IMAGE 2

IMAGE 3

IMAGE 4

Findings:
In this experiment, I found that centre focus is much more precise than the automatic selection option. If you were not very careful about where you wanted to place focus in the image, it would focus on the wrong part of the image.

In image 1, I focused on the beak of the owl, depressed the shutter half way, then moved the camera to include more space to the right, while trying to keep my focus on the owl's beak. It worked well and the owl stayed in good focus.

In images 2 and 3 I used a similar technique but from different angles, again to good effect.

In image 4, I wanted to see what would happen if I allowed the camera to focus where it wanted to after I had moved the camera and it focused on the centre of the tree outside the window in the far background, leaving the owl in obscurity.

Understanding Exposure

ISO is the measurement of how sensitive a camera is to light. A higher ISO is used in darker settings to make the camera more responsive to light, while lower settings are used in light conditions. The lower the ISO the better as high ISO numbers lead to a grainier image.

Below is an experiment conducted, one inside and one outside, using varying ISO levels on my Canon 550D.

IMAGE 1: Outside - ISO 100 - shows a clear image free from "digital noise"

IMAGE 2: Outside - ISO 200 - not quite as clear as ISO100, but still an acceptably clear image

IMAGE 3: Outside - ISO 400 - when magnified, image shows signs of graininess

IMAGE 4: Inside - ISO 800 - similar to images 1 - 2 as inside was slightly darker than outside

IMAGE 5: Inside - ISO 1600 - more digital noise beginning to show

IMAGE 6: Inside - ISO 3200 - more noise again. Beginning to see loss of detail when magnified

IMAGE 7: Inside - ISO 6400 - much more loss of detail and evidence of noise than previous images

Findings:
Images shot at a lower ISO proved to be clearer with more detail available on magnification. Image 7 showed graininess and digital noise and altogether a harder image to work with post-production. 

Images 1-2 and image 4 were relatively similar having adapted to the darker scene indoors and captured a clear image while compensating for lack of light by using an ISO of 800.

My Lenses

This is a list of my lenses and their specifications.

Lens 1:
Focal range - 18-55mm, 58mm
Aperture range - 1:3.5-5.6
Macro distance - 25cm
Focal length multiplier - 1.6x
Focal range with FLM conversion - 55 x 1.6 = 88mm
Image Stabiliser: Yes

Lens 2:
Focal range - 70-300mm
Aperture range - 4-5.6
Macro distance - 1.5m
Focal length multiplier - 1.6x
Focal range with FLM conversion - 300 x 1.6 = 480mm
Image Stabiliser: Yes

Lens 3:
Focal range - 50mm
Aperture range - 1:1.8
Macro distance - 0.45m
Focal length multiplier - 1.6x
Focal range with FLM conversion - 50 x 1.6 = 80mm
Image Stabiliser: No

Assessment 1, Activity 6 - Shutter Speed and Motion

The aim of this experiment was to discover the effect shutter speed has on capture of motion. Three techniques were used including a fast shutter speed to freeze motion, a slow shutter speed to blur motion and panning to create a blurred background with the subject in focus.

IMAGE 1: A fast moving subject using a high shutter speed to freeze the motion

Freezing: 80mm, ISO 100, Aperture 4.5, Shutter 1/4000

IMAGE 2: A photo of a moving subject while panning the camera (keeping the subject in focus while moving the camera) to create a blurred background

Panning: 35mm, ISO 100, Aperture 4.5, Shutter 0"4

IMAGE 3: Photo of a moving subject using slow shutter speed to blur the motion

Blurring: 35mm, ISO 400, Aperture 4.5, Shutter 0"3

Findings:
In image 1, I used my 70-300mm telephoto lens to get in close to the action from the fence at the rodeo. I used a shutter speed of 1/4000 to capture the motion as the bull tried to buck its rider. I also used the continuous shooting mode to capture frames very quickly so as not to miss the action taking place. With the shutter this fast, there was no blurring of the movement at all.

In image 2, I photographed a moving bike. On my tripod, I used a relatively slow shutter speed of 0"4 and used the tripod swivel top to move the camera to keep the subject in the middle of the frame while the shutter was open. The background has a nice blurred effect, however the subject is not as in focus as I would have liked. Next time I will try handheld as opposed to the tripod.

In image 3, I rolled a bright candle stick holder across the floor and photographed it from above using a 35mm lens, a tripod and a relatively slow shutter speed of 0"3 seconds. The effect was a movement blur of the orange candle stick while the background remained stationary. The longer the shutter was left open, the more blue was produced. 

Assessment 1: Activity 5 - Effect of Focal Length & Aperture on Depth of Field

This experiment aimed to discover the effect focal length and aperture have on the depth of field in an image. 

The following photos were taken roughly 2 metres from subject (the blue cruiser), on a tripod with the background over 10 metres away.

IMAGE 1: 50mm, ISO 100, f/4, 1/100

IMAGE 2: 50mm, ISO 400, f/8, 1/80

IMAGE 3: 50mm, ISO 800, f/16, 1/50

IMAGE 4: 28mm, ISO 100, f/4.5, 1/80

IMAGE 5: 28mm, ISO 200, F/8, 1/40

IMAGE 6: 28mm, ISO 400, f/16, 1/40

IMAGE 7: 85mm, ISO 200, f/4, 1/125

IMAGE 8: 85mm, ISO 800, f/8, 1/125

IMAGE 9:  85mm, ISO 800, f/16, 1/30

Findings:
The above photos have shown that as the aperture decreased (higher f stop number), the depth of field became larger. More of the background was in focus and there was less emphasis on the subject. With the larger aperture of f/4, the background produced a soft and blurry effect which trained focus to the subject. 

The varying focal lengths also had a large impact on the image. The 50mm fixed lens was cropped in to a medium amount. There was not a wide expanse to either side of the subject. The 28mm lens showed a wide expanse to the sides of the subject and looked oddly distorted and out of proportion. And the 85mm telephoto lens cropped the image in very close, leaving very little in the background and focusing solely on the subject.  

Assessment 1, Activity 4 - Exposure

This exercise aimed to show the effect of altering exposure on an image in different lighting circumstances. 

Task 1 involved shooting an object with a strong back light, an object with a very dark background and a light toned subject.

TASK 1:

IMAGE 1: A subject with a very light background

(50mm, ISO 100, f4.0, 1/500)

Image 1 was taken with the sun in the background of the object and the sky was very bright. Consequently, the side of the pig without sun was very dark (left image). I lightened the image by a third of a stop (+1/3) as seen on the right so as to lighten the shadows but try not to overexpose the sky.

 IMAGE 2: An subject with a very dark background

(50mm, ISO 100, f4.0, 1/80)
Image 2 was taken with dark bushes in the background, making the subject appear much lighter than it's surroundings (left image). I lightened the image by two thirds of a stop (+2/3) to make the background less oppressive. 

IMAGE 3: A light toned subject

(50mm, ISO 100, f4.0, 1/400)
This image was shot in good light, however I lightened the image by two thirds of a stop (+2/3) to brighten it up.


TASK 2:

Task 2 involved experimentation with bracketing. Below are 7 images taken on a tripod of a pavilion which had both shadows (inside the pavilion) and light (on the ground in front and on the roof).

As can be seen in the above images, I varied the photo by several stops of light. Image 1 is far too dark and shadowed, while image 7 is far to overexposed and bright. The ground is so bright it disappears. I think the perfect exposure is at +0.7  (image 5). There is enough light to brighten the shadows in the gazebo but not so much that is makes the ground and roof look blown out.

Assessment 1, Activity 3 - Focal Lengths

This experiment aims to show the difference in background focus when using different focal lengths. 

To conduct this exercise, I used my tripod and three different lenses on my Canon 550D: a 18-55mm lens, a fixed 50mm lens and a 70-300mm telephoto lens.

My subject was positioned roughly 4 metres from his background.

IMAGE 1: 24mm focal length, ISO 100, f/4.0, 1/6sec

IMAGE 2: 50mm focal length, ISO 100, f/4.0, 1/6sec

IMAGE 3: 100mm focal length, ISO 100, f/4.0, 1/8sec

Findings:

This experiment has shown a massive difference in both background and foreground across all three lenses.

In image 1, the subject appears somewhat distorted at a focal length of 24mm. As well as this, the background is still fairly focused and appears to be 3-4 meters away from the subject. There is quite a wide view in the background.

In image 2, using a focal length of 50mm, the subject appears less distorted and more in proportion. The background appears to be a lot closer to the subject and is less focused which draws attention to the subject more than image 1. The range of view is also a lot smaller. Only a portion of the painting on the wall can be seen in the top left corner, while in image 1, the entire framed painting was visible in the image.

Image 3 creates a different image again. The background is even more out of focus than in image 2, appearing to be closer again and the field of view to the sides is much smaller. Together, these two effects help to draw attention almost solely to the subject.

This exercise was an eye-opener for me as I would normally use my 18-55mm lens (used in image 1) for the majority of my shots. However, my 70-300mm telephoto lens (used in image 3) took a much more balanced and proportioned image with a smaller depth of field which was perfect for this scene.