Category Archives: Focus

Focus

Exercise – Panning With Different Shutter Speeds

The aim of this exercise was to practice panning to track a moving subject, and compare results when doing so using different shutter speeds. In this case, the subject is a girl riding a bicycle. I tried to capture the photographic instant at about the same point in the subjects’ position relative to the camera and background, so as to make easier comparisons.

 

Photo 1 – 1/200th second

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At this shutter speed, motion is practically frozen, except for maybe in the spokes of the bike.

 

Photo 2 – 1/100th second

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Motion in the spokes now a little more blurred, as parts of the riders’ body, the feet particularly. Still able to keep a decent track of the subject.

 

Photo 3 – 1/50th second

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Spokes much more blurred, motion of the rider now more obvious, as is the background pavement.

 

Photo 4 – 1/25th second

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A good sense of the speed of the subject is gained in this image. Tracking was still easily maintained.

 

Photo 5 – 1/10 second

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Background elements now indistinctly blurred, and every part of the image suggests a subject in full motion.

 

Photo 6 – 1/2 second

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It now became somewhat harder to keep a track of the subject long enough for the long shutter speed to maintain an accurate register of the subject in motion.

 

Photo 7 – 1 second

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I considered this 1 second exposure to be at the limit of being able to track the subject and still retain enough detail and information as to be identifiable. Timing was also an issue, the subject moved rapidly enough that deciding when to click the shutter became increasingly difficult and several attempts had to be made.

 

I think the use or absence of motion blur in an image is entirely subjective. That is, whether it is ¬†successful as an image in terms of its’ aesthetic quality depends on the intended purpose of the photo and the expectations of the image viewer. In the case of the exercises above I find that for the water spray, freezing the droplets enough presents a more interesting image purely for the fact that it’s a sight uncommonly seen. Water droplets don’t spend much time hanging around in mid-air to allow a viewer a chance to observe their quality. Whereas for the girl on the bike, a sense of speed isolates the subject from the background, and lends a somewhat warmer quality to the image in general, despite the conditions on that particular day being cold and overcast. So, the two photos I would choose for the preferred qualities mentioned above are:

 

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Exercise – Shutter Speeds

This exercise demonstrates the effect of varied shutter speeds has on the ability to stop motion, or not, of a given photographic subject. In this instance I use water sprinkling out of a shower head. The camera was mounted on a tripod and a Nikkor AF-S 50mm lens used as the lens. Initially due to low light conditions, I tried using a flash, but could only sync it up to 1/200 shutter speed. I then tried a single bright LED torch, hoping to provide a constant light source, mitigating the cameras’ tendency to compensate for varying shutter speeds by opening or closing the aperture to maintain a constant exposure (which it was only unevenly able to do).

 

Photo 1 –¬†1/800th second

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The camera tried to compensate for the generally low light condition and fast shutter speed but image still appears darker than was actually the case. Motion of the water droplets ahs not been adequately frozen.

 

Photo 2 – 1/500th second

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Blurring due to motion somewhat more apparent in this image.

 

Photo 3 – 1/100th second

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Photo 4 – 1/50 second

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Photo 5 – 1/10th second

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Photo 6 – 1 second

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Droplet motion now renders as an indistinct blur.

 

Photo 7 – 3 seconds

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One of the aims of the exercise was to find the slowest shutter at which the apparent motion appears to be frozen, and I have to say that even a 1/800th shutter speed did not seem to show this. I note however that using an on-camera flash, rather than the torch, at 1/200th shutter speed did freeze the action enough, as shown below:

 

Photo 8 – 1/200th second, with flash

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Exercise – Focus At Different Apertures

For this exercise, a series of photos taken with a fixed focus point but varying apertures sizes was required.

I chose an unusual carpet in my home that I thought with careful framing and positioning of the camera , might give obvious results,¬†despite the random nature of the carpets’ colour and pattern.

First photo – aperture f/1.8 with the limits of sharpness indicated between the white lines.

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Second photo – aperture f/8:

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Third photo – aperture f/16:

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I think the above does show the effect differing aperture sizes has on the depth of field in an image.

Exercise – Focus With A Set Aperture

This exercise required the taking of several photos of the same scene at varying aperture settings. I chose a nearby Buddhist stupa that had a number of prayers wheels aligned in a way that would give useful results. I elected not to use a tripod for this series of photos, and I mounted a Nikkor AF-S 50mm lens on the camera. Aperture was set at its’ widest; f/1.8

First photo – near focus point:

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Second photo – mid-focus point:

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Third photo – far focus point:

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Of the three photos I prefer the one with the closest focus point. I think in an image like this, where there are several instances of a particular object or subject in view, a close focus point shows quite clearly what that subject actually is, and the detail on it is very discernable. Your eye is drawn immediately to the first prayer wheel, and then moves deeper into the image. Because the first wheel is in sharp focus, and given the very wide aperture setting, the last prayer wheel is deeply out of focus, or blurry, which is more pleasing to the eye. Whereas a mid-focus point only allows a somewhat milder blur quality to the first and last wheels.

Link to higher resolution TIFF image files