Digital Photographic Practice: January 2014

Sunday 26 January 2014

Assignment Two - Seeing like your camera - submission

The assignment required three shots from four different situations that would produce challenges in contrast and dynamic range. All the shots presented were shot as JPEGs with no post-processing. For one category, the images were presented twice to show improvements between the first and second attempts.

Street scene in the middle of a clear, sunny day - narrow street and high buildings which cast deep, long shadows (parts one and two)

For this situation, I chose a study of One Canada Square (the tall pointy building) in Canary Wharf. In all cases, Active-D lighting was switched off, as I had realised recently that having this engaged was causing noise. I also find the Auto white balance on my camera to be very accurate and so I only change this when I want to deliberately change the warmth of the light.

Part One

Three scenes - initial shots (in all these Active-D lighting was switched off):

ISO 200 1/500s f/9.5

One Canada Square is as I discovered, a difficult building to photograph. The top of the building reflects a lot of light, and the bottom is in dark shadow. Composition is also tricky because of its height! I opted for a diagonal stance so as to add a bit of drama. Matrix metering. White balance Auto. Focal point is on the centre of the frame. In trying not to blow out the glare from the building, I underexposed with the result that the bottom is too dark.

ISO 200 1/125s f/8

View of One Canada Square again, from a lower perspective. This illustrates very well the problem of the sun around midday reflecting from the building causing burnt highlights. Also, the clocks from this view are not aligned very nicely. Matrix metering. White balance Auto.

ISO 200 1/180s f/13

For my first shot of this view, I used centre-weighted metering and focused right at the end of the street; I was trying to capture the sheen of the buildings in the middle. This however made the foreground seem quite dark. White balance Auto.

Part Two (improvements)

ISO 200 1/250s f/9.5

For my improvement to the first scene, I reduced the shutter speed which was still fast enough not to blow out the glare on the building. Matrix metering retained.

ISO 200 1/180s f/8

For my improvement to the second view, I had to change viewpoints and composition, and also waited half an hour for the sun to move further to the left. The glare previously was so bright and the foreground so dark, there was no other option. I used the clock on the left-hand side as my focal point, crouched to get below the glare, retained matrix metering, and increased shutter speed. The little girl on her scooter entering the frame was an added bonus, injecting a splash of colour into what is a very grey scene!

My third image was improved slightly by moving forwards a little, slowing down the shutter speed to allow more light in and changing the metering to matrix to provide a more balanced distribution of light. I also focused slightly higher up in the frame on the building right at the end of the road.

Early morning or late evening landscapes with low-angle incident light

These are all late evening scenes in this category.

ISO 200 1/250s f/8

Brightness of the light reflecting snow against the vegetation in the bottom. Shot in Reykjavik on New Year's Day in the afternoon. I wanted the photograph to have a balanced exposure and to retain the delicate colours of the sky and cloud, and so used matrix metering. With Active D lighting switched on I needed a low ISO, and so this influenced the shutter speed and aperture. I could not use a tripod as it was too windy.

ISO 200 1/250s f/4.8

View of the Isle of Dogs through the gates of the Thames Barrier. The exposure in this image is good; there is a bit of darkness in the bottom of the gate, but a good trade off for the clarity of the buildings of Canary Wharf in the distance. What I should have done though (maybe) was to have changed the White Balance in shooting to direct sunlight to have enhanced the redness of the scene, although the image taken is accurate of the lighting at the time. It was more peach/pink than red on the day! Matrix metering and Active D-lighting off.

ISO 100 30s f/16

Same scene as above, but different lens and shot with a tripod and big stopper filter (9 stop); and also about shot around ten minutes earlier. The actual exposure used with the stopper resulted in the image being 1 stop over exposed in practice. The exercise did not allow for processing, but I would however crop this image in practice to remove the artifact in the top left-hand corner (my camera view point is only about 90% of what it takes) and also to remove some of the water to produce a longer image (see Reflections). Spot metering (I wanted to really capture the shine of the gates) and Active-D lighting off.

Any back-lit scene whether in direct or indirect light

ISO 200 1/30s f/11

West view from Albert Bridge in London at sunset. I wanted to keep the ISO as low as I could (to minimise the risk of grain with the amount of dark in the scene) with shooting handheld as slow as possible to gain maximum stillness in the water. Matrix metering to get an even exposure. Active D lighting switched off.

ISO 100 1/350s f/22

Another sunset silhouette view taken from the Saga Museum in Reykjavik. My priority here was maximum sunset colour with the sculptures in the foreground as dark as possible. I also particularly wanted the sun to produce the starburst effect so I had to set the aperture as high as possible and the ISO as low as possible to avoid the potential for noise. I found an angle where the sun was just visible and also refleting some warmth on to the sculptures, and underexposed slightly.

ISO 200 30s f/2.8

This is a very weird image taken in Iceland of Kirkjufell at around midnight and one that I had wished for but not looking like this! The back-lighting is provided by the Aurora just visible between the clouds. There was no ambient lighting at all in the scene. The green lighting in fact was not visible to the eye - only to the camera. I knew that to photograph the Aurora you need a high ISO and the widest aperture possible, so I set the camera on my tripod and exposed for the average time with matrix metering. Had the sky been clearer, I think a 20s exposure would have been better to see the lights dance. I would definitely crop the top of the frame out to produce a pillar box format.

Scenes which include objects of very different reflectivity, even in flat light such as an overcast day

ISO 400 1/30s f/4.8 -0.5EV

Metal, ice and water: taken in Reykjavik at around 10.30am. The biggest difficulty with this shot was to get close enough to the sculpture due to the ice and set up a tripod (it was freezing). I resolved this by finding the ISO that would allow me to shoot hand held. My wide-angle lens is very fast, so and aperture of f/4.8 was fine - I didn't want too much detail from the background. I underexposed half a stop to retain the cold blueness of the scene and used matrix metering, but spot metering might have been more appropriate here?

ISO 400 1/45s f/8 -0.5 EV

Painted metals with different reflectivity - shiny and matt; taken in Reykjavik from a boat. The biggest challenge here was keeping the shot in focus as I was actually set up for whale watching with 3D focus...I used centre-weighted metering to make the helicopter (whale) stand out more, I wanted a slow shutter-speed to capture the movement of the blades and f/8 to keep the foreground sharp but the background not so sharp.

ISO 200 1/30s f/6.7 -1.5 EV

St George Wharf Tower in London taken in sunset on 11 January 2014 looking west from Albert Bridge. I was very taken by the reflection of the sunset in the tower (steel and glass) plus the mauve in the sky and the reflection in the water. I found I had to underexpose to reduce highlight clipping from the reflection on the building. I shot in shutter priority handheld to keep the shutter speed slow to keep the water as still as possible. Matrix metering again to maintain an even exposure, but spot metering or centre-weighted (focused on the tower) might also have been appropriate to enhance the reflectivity of the building?

Assignment Two - Seeing like your camera - preparation

Well, the honest truth is I didn't prepare for this. I had got very behind on my coursework during the November - January period (changing jobs, Xmas, dreadful weather, holiday, January tax return etc etc) and so lost continuity of thought during Part Two of the course. In addition to that I had understood that it's important to know what the dynamic range of your camera is and its limitations, but did not really understand how or why using spot metering helped the situation. I find my camera works excellently with matrix metering in most conditions (using blinkies and ability to over or under-expose) - I occasionally switch to centre-weighted (e.g. photographing single shiny objects like helicopters), but on the whole I stick with matrix metering. I generally find that when I switch metering, it becomes hard to find the right exposure and the results are often over-exposed. I think I would probably use spot metering more if I shot scenes that were back-lit but where I wanted the subject to be visible, rather than silhouetted. In practice though, I mostly wanted my subject to be silhouetted, except for the mountain which I shot on a long exposure.

Feeling that time was against me, I decided to shoot as/when situations arose whilst on holiday in Iceland over New Year. The remainder of the shots to be taken in London when the weather was appropriate. Because I am primarily an outdoors photographer, I was not interested in experimenting indoors with different lighting conditions, although I appreciate I could have done this from the point of view of learning.

The photographs I took were purely for the purposes of this assignment. There was no other motive, audience, theme or attempt to find personal voice or meaning. This collection of pictures are in fact an attempt to do the best that I could do with the lighting available at the time. I identified my four situations from choices that would enable me to shoot outdoors:

Street scene in the middle of a clear, sunny day - narrow streets and high buildings which cast deep, long shadows: planned to be shot in Canary Wharf where I work - which involved a long wait for lunchtime in the right conditions!
Early morning or late evening landscapes with low-angle incident light: initially shot in Iceland but I didn't get the right level of light contrast for all of them, so I took a few in London also
Any back-lit scene, whether in direct or indirect light: shot in Iceland and London
Scenes which include objects of very different reflectivity, even in flat light such as an overcast day: shot in Iceland and London.

One lesson learnt here is that relying on holiday photographs to produce assignment work when on a tour (with little choice over timetable, scenery and other people getting in the way) is a bit like the Masterchef chocolate fondant idea - basically asking for trouble! But I have no doubt that I will do this again, as I like the variety of locations.

I now appreciate that I really need to understand more about what the three metering options do; where time permits I will try to take each photograph on the three settings for a while to get to grips with this!

I am looking forward to moving on to Part Three of the course and working with black and white.

Scene dynamic range

Following on from the previous exercise "Your camera's dynamic range" and again using this f-stop table (accessed on 26 January 2014) to calculate the range, this exercise continued to measure dynamic range in a variety of scenes using the same process as previously.

Scene 1 - garden fence

The dynamic range in this scene was only 0.63, which surprised me - to the naked eye the scene looked really bright and "contrasty".

Scene 2 - view from upstairs window

For this scene, I forgot to change the metering to spot when taking the darkest and lightest measurements; I also realise now that my darkest measurement was outside the scene of the original shot! But - it showed that in this case, with my 55-300mm zoom, a 1.95 dynamic range. Again, to the eye, the scene looks bright and contrasty, but the camera copes very well.

Scene 3 - View from Reykjavik Saga Museum:

Again, I was surprised by the low range of the scene 1.53 stops; the light was so bright and clear that I was expecting a greater range.

Scene 4 - Low light landscape in Iceland

In this scene, the brightness of the snow wasn't bright enough to capture a difference. The dynamic range was 0!

Scene 5 - Albert Bridge

This scene produced a higher range than the above experiments: 2.43. I forgot to switch to spot for the measurements - had I done so the range would have been greater. But I don't think I have yet found out the extent of the range of my camera; so I need to continue with this exercise on brighter days.

And one fantastic missed opportunity :( - Reykjavik Cathedral

But here is how the camera coped - this is the lost highlights view:

Your camera's dynamic range

The objective of this exercise was to measure the dynamic range of a camera. I tried to find out via the internet what the official dynamic range of my Nikon D5000 is and this varied between reviewers. I also realised from my research, and from completing this and the next exercise, Scene Dynamic Range, that it varied depending on the lens being used (as the end of scale readings are limited by the lens) and also the ISO used. I think on average my camera is capable of reading a scene of around 8 stops and producing reasonable results.

Unfortunately the time of year where this exercise fell in my schedule was in December 2013, which was dark, gloomy, wet...very little opportunities for high contrast photography unless of course the days of bright sunshine when I was in the office! :(

So, eventually a day came with the right lighting: 29 December 2013.

Here is the initial shot of the scene (first image below), with High ISO NR turned off. Note that Active D-lighting was set to High (I later turned this off from my basic settings as I discovered that this was the factor affecting noise performance!). All images were set to ISO 100 and shutter speed: 1/750s, thus allowing the aperture to adjust and calculate the dynamic range. For this exercise I used my prime 35mm f/1.8G lens. The scene was shot so that the highlight clipping only just started to show (see second image below), resulting in the exposure being 2 stops underexposed from the average reading calculated by the camera on matrix.

I then switched to spot metering and measured the brightest and darkest patches, by moving in close:

I found that in the brightest area, the aperture adjusted to f/11 and in the darkest area to f/1.8 (which is the widest the lens will allow). Referring to this website's f-stop table (accessed for reference on 26 January 2014) this scene had a dynamic range of 5.22.

Looking at the point sampler (pixel value) in my NX2 software, the highest value I could find in the shiny patch on the car was 252.

Same image with brightness adjusted until dark details are visible; no noise or conflict between dark and noise present, but the image is now clearly too bright!

Although zoomed in to 100% magnification, you can clearly see that there is noise!

All in all, the dynamic range was smaller than I expected. But, the lower end was limited by the lens, and the upper end might have been higher, had I used a faster shutter speed.

Saturday 11 January 2014

Bradford Washburn

I visited the Bradford Washburn exhibition today at the Michael Hoppen Gallery in Chelsea. I was interested in this exhibition as I often photograph mountain scenery myself and particularly like the black and white dramatic landscapes that you can literally "walk into" (see notes previous trip to Ansel Adams exhibition). This was a small exhibition - around 10 pictures - but all stunning. The use of light was amazing! This was particularly interesting as I am nearing the end of section two of DPP dealing with dynamic range. So I was interested to see how aerial photographer Washburn captured light in such a dramatic way.

These images in particular demonstrated the use of light and tone, with the people captured adding scale and a sense of drama (think he must have used a polariser?).