Wednesday, 29 December 2010

Part 1 The Frame; Project: Looking through the viewfinder

Exercise: Fitting the frame to the subject.
Objective: In this exercise I will experiment with and select a minimum of four different viewpoints to show an object in detail and how it relates to its surroundings.
Location: I have chosen the Spinnaker Tower in Portsmouth harbour as a large, easily accessible object.
Camera settings: I have set the camera to Programme mode and Auto focus (with manual override) as I find this works well for this type of situation. I am using a 18-200mm VR (vibration reduction) zoom lens.

Establishing Shot: 3924: 18mm, 1/160s, f6.3
This was taken with maximum angle of view  from the viewpoint at the  end of Broad Street, south of the tower. I decided that I would include the reflections in the water and framed the shot with the tower in the centre of the frame, showing the historic dockyard to the left with the modernised Gunwharf quay and housing to the right.

Immediate Area: 3932 : 26mm, 1/200s, f7.1 Before getting really close, I took this shot with the tower in its immediate surroundings, showing the shopping centre and the yacht quay with the tower reflecting the design of the boat  masts.

In Close: 3943: 18mm,1/125s, f5.6
Concentrating on the superstructure of the tower, above the reception centre and restaurant, I saw this serpentine curve. As my lens was set on maximum angle of view I was unable to make the top if the spire reach the top border without including more of  the distracting building at the bottom of the frame. I was also unhappy with the metal stay of the shopping centre roof at the top right.

In Closer: 3952: 22mm, 1/40s, f3.8. By tilting the camera and getting closer, I got this cleaner shot from the other side of the tower.

                                                                                                                                                       Viewing Gallery: 3935: 170mm, 1/160s, f5.6. Zooming in close I isolated the details of the three viewing floors  showing the people looking down from 110m above me.

Detail from below: 3949: 18mm, 1/100s, f5. Looking up at the glass floor of the viewing gallery through the restaurant's veranda roof.

Camber Dock: 3930: 34mm, 1/200s, f7.1. Although at 170m the Spinnaker Tower dominates most of Portsea Island and the dockyard, Camber dock and Gunwharf are associated with it and I have attempted to show the everyday working environment that surrounds the tower. The cropped images derived from this one are shown below and prints of all images for this exercise can be found in my learning log display book.

I tried four crops of the image. This top one, a horizontal trim is not really different from the original.

The two vertical crops work quite well, the narrower one is the best as it emphasises the height of the tower.

 This square crop is also works well. I find that my eye is drawn from the Spinnaker tower to the clock tower, down to the water then diagonally across to the left and back to the tower again.

Although I was reasonably happy with this image, it doesn't really work to place the tower in its environment. I did take  the image below from Southsea Common which gives a wider view of the tower's relationship to Portsmouth Cathedral and Southsea. Unfortunately the light was fading fast and I didn't have my tripod so I wound the ISO up to 3200. Consequently the image has a lot of noise but I have made crops of the image in an attempt to show the tower in  the wider landscape.

Southsea Common. 3955: 70mm, 1/30s, f5. his shot, from further away, shows the tower's relationship with the Cathedral and its proximity to Southsea.

In this first crop, I have removed a lot of the wasted space around the edges and shifted the tower to the right. This seems to works well although it does not give any idea of the relative sizes  of the two dominant objects as they both appear on the horizon but the Spinnaker tower is much further away.

I think this crop is more successful. By restricting the filed of view I have established a size relationship between the lamppost on the left, the Cathedral bell tower and the Spinnaker tower. The diagonal line which joins the tops of these three points seems to push the tower further back, giving more of a sense of scale.

What did I learn? 
Havimg completed the exercise I can appreciate the importance of spending  time composing the shot with your eye to the viewfinder before operating the shutter. If I was to attempt this exercise again I would allow more time. You can see from my images that the light changed very quickly towards the end of the afternoon. I guess that's a consquence of working in December.

Tuesday, 28 December 2010

Project: Photographing Movement (continued...)

Exercise: Panning with different shutter speeds.

Objective: This exercise will show the effects achieved by panning the camera to follow the movement of an object, with progressively slower shutter speeds.
Location:  I knew that I would have difficulty panning from the layby I chose in the last exercise. The cars were moving too fast and I was very close to the carriageway. I moved to a junction in a 30mph zone where I was able to stand back from the roadside and pan in both directions.
Camera Settings: To complete this exercise as quickly as possible (in freezing conditions) I chose to use a fast (f1.8) 35mm lens for my camera which allowed me to use each one of the range of shutter speeds from 1/1000 sec up to 1/5 sec. (24 in all. I have selected  only 12 to display  here) I also used shutter priority mode  to set the aperture to match the manually selected shutter speed. To make sure I got a good selection of shots, I set the shutter release to continuous high speed mode (4.5 fps) which resulted in three or four frames of each passing car. The exposure information is below each image. The ISO setting was 200 for all frames.

3818: 1/1000s f1.8. The car is sharp with only a very slight blurring of the wheel hubs when viewed at 100%. The background is slightly blurred but this may be a result of the shallow depth of field at this large aperture. Note that the car travelling in the opposite direction is blurred by the combination of it's own motion and the movement of the camera in the opposite direction.

3824: 1/640s f 2.2 The car is sharp with slight blurring of the wheel hubs but the background is less sharp than previously.

3832: 1/400s f3.2. At this speed, the car is still sharp, the wheels still show slight blurring but the background is showing more blur.

3839: 1/250s f4.5. The car is still sharp, the wheels are more blurred as is the background.

3847: 1/160s f5.6. Even at this small size, the blurring of the wheels and background are noticeable. The images are starting to look more dynamic.

3858: 1/100s f7.1 The motion blur of the background is more pronounced and it is more difficult to pan and keep the car sharp at this shutter speed.

3873: 1/40s f8. Although the car is now blurred, the background is nicely streaked and there is a real feeling of movement.

3882: 1/25s f16. The car is still reasonably sharp and the streaked backround really moves it along.

3888: 1/15s f13. The car is now starting to lose definition but the image still gives the feeling of movement and excitement.

3907: 1/10s f14. It is now difficult to pan at this shutter speed and maintain sharpness. The overall impression is still one of action.

3914: 1/8s f20. Difficult to be consistent with the panning but still an acceptable image.

3921: 1/5s f22. Right at the limit for hand held operation,  it's not sharp anywhere but still says speed.

What did I learn? As the shutter speed increases the depiction of speed is easier to achieve. It is difficult to pan consistently at slow shutter speeds. I think perhaps I need more practise and "follow through" with the movement after the shutter has released. I may have had better results if I'd used my tripod to pivot the camera but I didn't feel it would give me the spontaneity that depicting speed demands. The blurring of the vehicles seems to add someting to the dynamism of the images. I have practised using the shutter priority mode on my camera and the shutter release in continuous high speed mode.

Which pictures do I prefer from the two exercises?

Shutter speeds: Until the shutter speed reaches 1/125, the images are fairly static. At this point the emphasis on the contrast between the static and moving obects becomes apparent. My favourite image from this series is 3746 (1/50s f14). The vehicle is recognisable as a tanker, moving at speed and fills 75% of the field of view. The kerb with its roadside reflector, emphasises the danger posed by the unfenced pavement. You can almost hear the noise and feel the wind as it passes.

Panning at different shutter speeds: Although I did not achieve a very sharp picture of a car with a streaked background, I suspect that it may looked "staged" (although blurred, spinning wheels would add realism). I liked the image above 3921 (1/5s f22). Looking at the larger version, the road surface, kerb, fences, background buildings and trees are all streaked into parallel horizontal bands which give movement across the frame. The driver can be seen staring intently ahead. The bonnet, windscreen and roofline have a highlight which indicates clear open space ahead. None of the image is sharp but that just reinforces the brevity and spontaneity of the moment. The sense of speed is exaggerated, 30mph looks more like 100mph.

I have printed and placed these two images in the display folder of my learning log.

Project: Photographing Movement

Exercise: Shutter Speeds.                                                                                     24/12/2010

Objective: This exercise will show the effect of a range of shutter speeds on the image; i.e 1/800 down to 1/6 second,  while recording movement past a fixed viewpoint.
Location: I chose a busy dual carriageway and photographed moving vehicles at speeds of between 50 -70 mph from a layby.
Camera settings: My camera was set on manual mode and fixed onto a tripod. I adjusted the shutter speed for each exposure starting at 1/800s down to 1/6s and adjusted  the aperture manually using the in built exposure meter. I did this to experience using the meter as I have only previously used manual mode in the studio with an off camera flash meter. The exposure information  is shown below each frame.

3727: 1/800s f3.8. Even at this relatively fast shutter speed, the vehicle very slightly blurred.

3730: 1/640s f3.8. There is more blur on this image. Even on the original image at 100% the smaller writing on the side panel is unreadable.

3733: 1/400s f5. Again, the blur is more apparent and the patterns of the wheel hubs are starting to distort with the speed of the wheels.

3735: 1/250s f7.1 The front and rear edges of the vehicle are less distinct and the wheel hubs are now starting to distort into oval shapes.

3738: 1/125s f9.  The details of the vehicles are becoming less distinct although you can tell the vehicle type.

3743: 1/80 f11. Vehicles are starting to leave a distinct trail as the shutter speed decreases.

3746: 1/50s f14. Definite elongation of the blur at this speed.

3747: 1/25s f20. Notice how the wheel hub details have produced a repeated pattern below the vehicle.

 3751: 1/15 f25 (minimum aperture at this ISO). Very few details are discernable, apart from the colour.

3756: 1/8s f22. (to use a slower shutter speed I had to change the ISO from 400 to 100 for this shot) At this speed it was also difficult to catch the car in the frame.

3762: 1/6s f32. To achieve minimum aperture for this lens (18-200mm zoom) and a shutter duration of  1/6s,  I had to increase the focal length from 26mm to 55mm. At 1/6s, the vehicle is virtually transparent and elongated beyond the field of view.

What did I learn? A short shutter duration will render a moving object sharp and a progressively longer one will  blur the moving object in direct relation to it's duration. I also learned more about my camera's manual  exposure controls, the way I could vary the ISO setting to make use of  the smaller apertures and about the relationship of the maximum and minimum aperture to the focal length settings of a zoom lens.

Tuesday, 21 December 2010

Project: Focus (continued...)

Exercise: Focus at different apertures.

Objective: This exercise will demonstrate the how the area of sharpness (also called the depth of field) changes with aperture.

I made three photographs. For each, the camera was set on a tripod and focused at a point about half way between foreground and background. All settings were made manually. Higher resolution A4 size prints are available in my learning log display book, which indicate the area of sharpness more clearly.

1. I chose the largest aperture available for my zoom lens set at 38mm, which was f4.2. I adjusted the shutter to 1/20s. I have indicated  the area of sharpness with red lines on the image. It is quite shallow. 

2. Next, I chose the smallest aperture available, f29 and set the shutter to 1.6s. The area of sharpness is about 3 times that of the previous image as indicated by the lines on the image.

3. The third image had settings of f11 at 1/3s. As would be expected, the area of sharpness (depth of field) has fallen between the two extremes.

What have I learned?

The area of sharpness within the depth of the image can be controlled by the aperture of the lens. A large aperture gives a shallow depth of field (focus) which becomes deeper as the aperture is reduced. This can be used effectively in composing images, i.e. a shallow depth of field can be used to isolate and thereby highlight the key part of the image. It is used in portraiture to blur the background to remove distractions and bring the subject forward. An even textured, out of focus foreground can also be used effectively to add depth to a picture. See  the soldier picture below. I know from my experience that the focal length setting of the lens also effects the depth of field at the same aperture. Wide angle lenses have more depth of focus at a given aperture than telephoto lenses.

(These images were taken in room lighting. I reset the white balance on my camera to cool white fluorescent to remove the colour cast)

Friday, 17 December 2010

Project: Focus

I saw this photo on the cover of The MOD's  E2E quarterly magazine. (There is no byline for the photograph so I cannot attribute it) It illustrates perfectly the impact of sharp focus with a shallow depth of field.

With the following images, I was looking for a shortened perspective and spotted these shop signs in a nearby street. However, the irregular and relatively greater distances between the signs meant it was not an ideal subject to illustrate differential focusing effectively. They do show that with a wide aperture, the depth of field is limited and that when the lens is focused on a foreground object, more of the background depth is thrown out of focus.

Lens focal length 130mm, f5.6 @ 1/50s

I focused on the tiled wall to the right of the image. The green sign is just out of focus and all of the background is blurred. 

The same camera settings with the lens refocused on the green sign. The tiled wall is out of focus, the background is in focus back to the brown and cream sign, beyond that it is blurred to infinity.

I had no tripod with me to provide consistent framing for this subect and realised I would need a better subject to show the objective of this exercise.

Exercise: Focus with a set aperture.

Objective: This exercise will demonstrate the effect that can be achieved using a wide aperture in a scene that has depth.

For this exercise I chose a row of six workstations in a classroom, set my camera on a tripod and focused on three points within the depth of the scene. I included two red objects as a reference point.
Camera settings: Zoom focal length 50mm, aperture f4.8, shutter 1/13s. Lighting: fluorescent tubes (colour corrected post processing)

1. I focused on the closest edge of the keyboard in the first workstation, resulting in a very shallow depth of field of about 5cm.

2. Here I focused on the nearest edge of  the second keyboard and it can be seen that the depth of field extends for approximately 30cm.

3. For this example I focused on the third workstation mouse and the depth of field extends to the fourth workstation mouse, a depth of about 60cm. (this can be more clearly seen from a larger print of the image)

The first image's restricted depth of focus tends to leave your eye at the foreground  and at the bottom of the frame. There is nothing to draw your attention into the picture. The third image does get your eye moving along the desk, searching for the focus area but when you find it,  it's too  narrow to hold your attention for long. (also, the red pen and folder have more to do with grabbing your attention)

I think the second image is the best. There is sufficient out of focus detail at the bottom of the frame to indicate depth and enough blur in the background to place the keyboard at the centre of interest. Adding the red objects to the image was a mistake so I have recoloured those objects grey, to show the distracting effect that they have.

What have I learned?

Selective focusing with a narrow depth of field achieved with a wide aperture can isolate obects within a scene and create a centre of interest. Use red in a scene very carefully if you don't want it to dominate or distract.

Tuesday, 14 December 2010

Project: Getting to Know your Camera

Exercise: Focal Length and Angle of View (Field of View)

Objective: This exercise will demonstrate that the field of view narrows and distant objects appear larger in the frame as the focal length of the lens is increased.

Before starting this exercise, I searched the internet for information about the sensor size of my camera. it has an image sensor approx 24x16mm. Using the guidelines from the project text I calculated that the focal length of the 'standard' lens should be in the region of 30 - 40mm for this format. However, when I undertook the exercise keeping both eyes open and adjusting  the zoom until both images were the same size, the focal length scale on the 18-70mm zoom consistently showed 50mm+. After posting a question in the OCA Flickr group, (Can I believe my eyes?) I was assured by Rob and DaveB that they had experienced a similar effect. We all agreed that I was looking too deeply into the technical aspects of the exercise.

Using the 18-70mm zoom, I took the required photographs and noted that the focal length of the zoom was set at around 50mm when the viewfinder image in my right eye appeared the same size as the scene viewed with my left eye. Here are the photographs, taken near the junction of Bordon High Street with Chalet Hill. (For historical interest, to see a picture taken from a similar viewpoint in 1919 click here )

Zoom lens set at 50mm ('standard') f8 @ 1/125s AF on

Zoom lens set at 18mm (wide angle) f7.1 @ 1/200s AF on

Zoom Lens set at 70mm (telephoto) f5.6 @ 1/400s AF on

Upon returning to the viewpoint with the prints I had made, I found  that the 50mm focal length image could be viewed comfortably at  28 - 30cm from my eyes with the print matching the dimensions of the scene and the 70mm focal length image at 60 - 63cm i.e. arms length. The 18mm focal length image however, could not be viewed within my arms length, the central feature and even the foreground features (the manhole cover and the fence panel) were smaller than the actual scene even at arms length. If I had an assistant to hold the image, I would have expected it to be viewable  to scale possibly in excess of a metre from my eyes.

What have I learned?

As the focal length of the lens is increased, the field of view narrows. I have learned that the focal length of this 18-70mm zoom lens which matches the field of view of my eyes, is around 50mm on the zoom scale. When  the minimum focal length is chosen (18mm) there is some pincushion distortion at the edges of the frame. With the modest zoom range at the telephoto end (35-70mm), there is no noticable shortening of perspective.