Panning at Different Shutter Speeds

Using the same scene as previous exercise on Shutter Speeds with static position, this exercise was done with the camera being hand held and panned whilst taking shots.

Again, starting at 1 second and halving the exposure times up to the cameras maximum of 1/2000th second:



1 Second



1/2 Second



1/4 Second



1/8 Second



1/15 Second



1/30 Second



1/60 Second



1/125 Second



1/250 Second



1/500 Second



1/1000 Second



1/2000 Second

The vehicles in this series of images become Sharp at 1/60th second – a much slower shutter speed than the 1/500th second exposure when keeping the camera in a static position. Unlike the static exercise, people don’t become sharp because of panning.

Preference

The images taken using the panning technique look a lot better than when the camera was kept static. This was probably helped by it being a lot easier to keep the subject in the frame when panning.

The panned images above 1/60s have a static feel to them and are quite lifeless. My personal favourites are the 1/2 second and 1/8 second exposures because enough of the image has a level of sharpness to know what the subject is and they also have an enhanced sensation of speed (the image at 1/4s wasn’t very well captured).

The image at 1 second also has some appeal due to the different types of light and movement introduced by both the panning and long hand held exposure. A longer exposure could have created an interesting abstract image.

Shutter Speeds From A Static Position

This exercise is looking at the effect of shutter speeds when the camera is kept in a static position.

I aimed to fill the frame with the vehicles in the images but this was quite difficult. It would probably have been easier to be further back or use wider angle lens, however, the results still demonstrate the effect.

The following images were taken starting at 1 second exposures and halving exposure times until the camera limit was reached (1/2000th of a second):



1 Second



1/2 Second



1/4 Second



1/8 Second



1/15 Second



1/30 Second



1/60 Second



1/125 Second



1/250 Second



1/500 Second



1/1000 Second



1/2000 Second

Studying the images, it can be seen that the moving vehicles start to become sharp at the 1/500th exposure.

Within the images, there were two moving subjects, the cars and the people, which were moving at different speeds. I would estimate that the cars were moving around 15-20mph and the people were strolling probably around 2-3mph. The people start to become sharp in the 1/30th second exposure.

It’s worth noting that for this exercise, shutter priority was used and the camera was left using auto focus which has actually let these images down in 2 ways:

  1. To anticipate the vehicles being in the correct position for the image to be taken, I was half depressing the camera shutter button in order to be ready which was engaging the camera’s auto focus. At that point, there was no vehicle in the image so the camera has assumed I wanted to focus on the building behind the road.
  2. In order to achieve the correct exposure, the camera was reducing the aperture as the shutter speed was increasing. Once the widest aperture was reached, I manually boosted the ISO settings to allow the camera to continue using a consistent exposure. However, for this scene, a really wide aperture doesn’t seem appropriate. Due to the focusing issue above, it’s not possible to determine when the best aperture would have been achieved.

If I was to repeat this exercise, I would pre-focus the camera to be focused on the road and disengage the camera’s auto focus system (switch to manual focusing) and select a pre-determined aperture. From the previous aperture exercises, I would start by trying an aperture of f5.6 to ensure focus is spread across the vehicle but drops away when reaching the building. In order to do this, I would need to be adjusting the ISO as the shutter speeds increased, in order to maintain a consistent aperture.

Focusing With Different Apertures

As with the exercise for focusing with a fixed aperture, for this exercise another scene was selected which had depth.

Placing the camera on a small tripod, the central focus point was positioned on the fifth wheel in the row of bicycles, approximately in the center of the image and the camera was set to aperture priority. Images were taken at different stops of the aperture scale. The images below show the results of the widest aperture, a mid-range aperture and the narrowest aperture:



Wide Aperture - f1.8

At the widest aperture, the area of focus is very narrow and the only parts of the image that appeared in focus are the last bike light and the next wheel.



Middle Aperture - f8

Using a mid range aperture, the focus area has clearly extended based around the center point. All tires other than the very closest are now in focus (you can see the tread patterns) and at the back of the picture, focues appears to be falling away at the glass wall at the back of the image.



Narrow Aperture - f22

Selecting the narrowest aperture, the Focus area again can be seen to have extended as the front tread pattern is now visible, however, looking at the building in the background, focus appears to have been lost slightly. This could be described as the imaging appearing softer.

The apparent softening of the image is generally unexpected when comparing images taken with a narrower aperture, however, there is a technical feature which can become apparent when narrowing apertures known as diffraction as discribed here. The reason I believe this to be a demonstration of diffraction limitations is that looking at an image taken at f16, the image appears to be sharp all the way through the image:



Narrow Aperture - f16

Focusing With a Set Aperture

To study the affect of focusing with a wide aperture on a given scene, I selected a row of tree trunks against a garden wall. In order to emphasise the depth of field create by the wide aperture, a relatively acute angle was used.

Placing the camera on a tripod, I selected an aperture of f1.8 and then took a sequence of 11 images working from the right most focus point through to the left.

Below are 3 of the images taken with the focus point at the two ends and also the centre focus point:



Right Focus Point



Centre Focus Point



Left Focus Point

In all three images, the eye is naturally drawn to the in focus area as a first point of reference. Once the eye has settled on the area of focus and has had chance to process the detail of the area, I find that the eye then begins to look at the remainder of the image looking for secondary sites of information.

The images with the focus points set at either end seem to give the least satisfaction and with these images the eye seems to move away from the point of focus much quicker than when looking at the image with the point of focus in the centre. This image holds the eye for slightly longer and I then find that the eye tends to move to the bricks protruding from the wall.

In this scene, these bricks seem to provide a natural point for the eye to fall upon and I feel this is where the focus point should ideally be, as shown here:



Preferred Focus Point

Focal Length and Angle of View

Standard Focal Length

The standard focal length is that which provides a view matching our normal vision.

In order to find this standard view, I composed a scene where I knew branches of a tree would break the image boundary. Keeping both eyes open, with one looking through the cameras view finder, I adjusted the zoom lens until the image I was viewing through both eyes appeared to match.


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Standard View - 50mm

Checking the zoom setting on the lens barrel, it was showing a focal length of just short of 50mm, however, checking the exif of the image revealed that the camera had recorded the focal length as 50mm.

Wide Angle Focal Lengths

Leaving the camera set in the same position, I reduced the same zoom lens down to the widest focal length of 17 mm:


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17mm Focal Length

To go wider still, I then swapped the lens to an ultra wide angle lens, selecting the widest focal length available of 11mm:


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11mm Focal Length

Telephoto Focal Lengths

In order to switch to the telephoto end of the focal spectrum, I again had to switch lenses using the longest lens I had available, a 70-300mm zoom lens. To provide comparisons with the standard focal length, images were recorded at both the 70 and 300mm focal lengths of this lens:


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70mm Focal Length


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300mm Focal Length

Comparing the Focal Lengths

Comparing the wide angle and telephoto images with the image taken at the standard focal length shows that:

  • The wider focal lengths contain a larger amount of the scene than that shown in the standard view.
  • Objects in the images from the wider focal lengths appear smaller than those of the standard view.
  • Telescopic scenes show a lesser amount of the scene than that shown in the standard view.
  • Objects in the images from the telescopic focal lengths appear much bigger than those shown in the standard view.

After capturing the images, I downloaded them on to an iPad so that the captured images could be compared at a size roughly equal to A4. Starting with the image taken at the widest focal length, and working through to the image taken at the longest focal length, I tried to adjust the distance of the iPad from my eyes until it matched the scene in front of me:

Focal Length Approximate Distance From Eyes
11mm 2cm – this distance was getting so close it was actually difficult to focus on the image in front of me.
17mm 3cm
50mm 40cm – not quite a fully stretched arm but it was further than I would consider a comfortable reading range if I was holding a book.
70mm 50cm – a full arms length.
300mm This wasn’t possible to measure but it appeared it would have been many metres in front of me.

The final comparison I did of the images was to merge them all into one image and mark the boundaries of each focal length:


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Focal Length Comparison

The image shows a much greater difference between the outer edge, taken at 11mm, and the boundary of the image taken at 17mm than that of the next two boundaries taken at the 50mm and 70mm focal lengths.

Plotting the focal length against the relative pixel size in the merged image reveals that as focal lengths decrease there is an exponential relationship with the amount of a scene that will be included in the captured image:


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Focal Length vs Pixel Size