Light - Higher and Lower Sensitivity

Exercise: Higher and lower sensitivity (12 Photographs)

This exercise was again in two parts. The first part was to take similar shots at both normal and high sensitivity. All modern DSLR's have the ability to select the ISO prior to taking a photograph. The second part was to show how the ISO affects the quality of the photograph. 

What is ISO I hear you cry? 

With film cameras you would have had to change the film roll to adjust your cameras sensitivity to light. With digital cameras it is just a matter of altering a setting on the ISO dial to increase or decrease the cameras sensitivity to light. Its a numerical scale, if your camera is set to ISO 200 and you change to it to 400, it is now twice as sensitive to light as it was at 200. 

ISO is only one third of the equation when it comes to taking a well exposed photograph. The other two, which we have spoken about in previous exercises are aperture and shutter speed. These two work in conjunction with your ISO setting to capture a photograph that is the correct brightness.

To demonstrate how ISO can be used, the next photograph was taken at a fixed aperture of f16 with ISO set to 100.  Then the same photograph was taken at a higher ISO of 800 , by doing this it allowed the shutter speed to be increased. 

Nikon D4 200mm f16 @ 1/30sec at ISO 100 

This photograph was taken on an overcast day, the shutter speed of 1/30 using the focal length shown and hand holding the camera. This was far too slow to capture these cyclists without motion blur, or camera shake however minimal. 

Nikon D4 200mm f16 @ 1/250sec at ISO 800

By increasing the ISO to 800 I was able to select a shutter speed of 1/250. As you can clearly see the motion blur has been greatly reduced and the detail on the cyclist's shirt is clearly legible. 

I could have set a larger aperture of say f4, and left the ISO set to 100 and obtained the faster shutter speed that way, but I wanted to demonstrate the effect of increasing the ISO.  Remember the ISO is just one part of the three things; shutter speed and aperture are the other two that we can adjust to obtain the correctly exposed photograph. 

Nikon D4 200mm f13 @ 1/15sec ISO 100

A busy street scene taken at 1/15sec, with the selected shutter speed; any movement shown within the image is blurred. 

Nikon D4 200mm f13 @ 1/90sec ISO 800

Again by increasing the ISO to 800, thereby increasing the cameras sensitivity to light eight fold. A shutter speed of 1/90 freezes most of the blur within the image. 

Nikon D4 200mm f13 @ 1/180sec ISO 1250

By increasing the ISO still further the shutter speed has risen to 1/180sec eliminating any motion blur or camera shake within the image. 

Nikon D4 200mm f13 @ 1/10sec ISO 100

With the overcast conditions, coupled with the late afternoon light, has resulted in a shutter speed of 1/10sec. Any movement within the image is blurred. 

Nikon D4 200mm f13 @ 1/90sec ISO 800

Similar scene, same lighting conditions. Increasing the ISO, shows an increase in available shutter speed. 

Nikon D4 200mm f13 @ 1/180sec ISO 1250

Increasing the ISO, like the previous photographs has given a suitable shutter speed to freeze any movement within the image. 







So why don't we just use a high ISO all the time when taking photographs? Well the higher you boost the camera's ISO, the more noise you introduce into the image. Noise is akin to film grain, great if you want that grainy, arty look, but bad if you want a sharp landscape or portrait photograph. 

Nikon D4 200mm f8 @ 1/20sec ISO 100


This photograph has been been cropped and I have i've zoomed in so that it is possible to see if there is any noise in the darker areas of the image. 

As the image was taken with an ISO of 100, apart of camera shake and motion blur, no noise is apparent.   

Nikon D4 200mm f8 @ 1/180sec ISO 1250

By increasing the ISO I have eliminated any camera shake or motion blur, but the consequence of that is an increase in noise. 

This can be seen in this photograph as a speckled like texture over the entire image. 









Using the Nikon D4,  which is fantastic at high ISO's the noise only became apparent at an ISO of 1250 and above and only when the image was enlarged dramatically. When using my D300 the noise becomes noticeable at ISO 800, but again only when zoomed in. 

If you are going to print your photographs as 6"x4" prints, then the noise will not be an issue to worry about, however anything bigger than A4 size then noise will certainly have an effect on the image. 

Light - Measuring exposure 2

Exercise: Measuring Exposure Part 2 (36 Photographs)

For part 2, the task was to take 5-6 different photographs of any subject. For each photograph I was to take 5 exposures around what would be measured as the correct exposure. 

The first -1 stop darker, second- half a stop, the third -the average exposure, the fourth - half a stop lighter and finally the fifth- 1 stop lighter. 

As with the first part of this exercise, the following images were taken in the RAW format with minimal post production, and the D4 was set to 'M' manual. 

Not sure if this old BMW had been put out with the rubbish, but it certainly hasn't moved in a long time. 

Nikon D4 f11 @1/500sec ISO 800

The camera suggested 1/250sec for this scene to be correctly exposed with the selected aperture setting.

This photograph to the left was taken at 1 stop under with a speed of 1/500sec. This showed dark areas to the image were underexposed and clipping was present in these areas on the histogram. 

Nikon D4 f11 @ 1/350 sec ISO 800

1/2 stop under with a shutter speed of 1/350, there was minimal clipping present on the histogram. These settings give the image a darker look without losing too much of the details in the darker areas.

Nikon D4 - f11 @ 1/250sec ISO 800

The picture to the left, shows the correct setting of shutter speed with the selected aperture as suggested by the cameras sensor. 

Still a darker, gloomy photograph this is possibly down the areas of light to the edge of the frame causing the sensor to read that the scene was slightly brighter than it really was. 

Nikon D4 - f11 @ 1/180sec ISO 800

A brighter photograph taken at 1/2 stop over, the darker areas are better defined and the green wheelie bin stands out as a brighter green, as does the foliage in the foreground.

 Nikon D4 - f11 @ 1/125sec ISO 800

1 stop over exposed, the dark areas at the back of the photograph are now well exposed and the detail in the foliage is apparent. 

Even though this photograph is 1 stop over exposed it doesn't have the look of being too bright. 

As demonstrated in part 1 of this exercise, the metered settings suggested by the camera are not always correct. In the above series of photographs, in my opinion the 1/2 over exposed image has got the correct balance of dark and light. 

The A30 Underpass was a good challenge for the cameras sensor. The bright sunny areas at each end coupled with the dark under the bridge made for some interesting results. 

Nikon D4 - f4 @1/350sec ISO 800

The suggested shutter speed for the aperture setting of f4 was 1/180sec, 1 stop under being 1/350sec. 

The sign in the distance had the sun reflecting off it therefore this was shown as a clipped highlight on the histogram, along with the grass verge below it. The dark area under the bridge was dark, but not as much as to show as the detail of concrete walls. 

Nikon D4 - f4 @ 1/250 sec ISO 800

1/2 stop under brightens the overall photograph slightly, there was more highlight clipping around the area of the sign and a change is seen in the colour of the green foliage. 

Nikon D4 f4 @ 1/180 sec ISO 800

The metered setting, shows that the area under the roof of the bridge is clearer and the blocks of concrete are visible. However the area around the sign is now visibly blown out.

The matrix setting of the cameras meter has taken the majority of its reading from the foreground and dark areas of the underpass, therefore creating the clipped area. 

Nikon D4 f4 @ 1/125 sec ISO 800

1/2 stop over, lightens up the underpass but creates a larger clipped area around the sign. 

Nikon D4 f4 @ 1/90 sec ISO 800

1 stop over, creates a photograph that is clearly over exposed and looks washed out. The clipped area around the sign now consists of the sign, verge and road. The bright stops in the foreground now also show as clipped highlights. 

In contrast to the first series of photographs of the abandoned car, the 1/2 stop under exposed photograph here is, in my opinion the best combination of dark and light and therefore makes the better photograph. 

Nikon D4 f4 @ 1/250 sec ISO 800

Photographing in a dense wood looking upwards towards the sky is going to be a challenge for any camera's metering system. The problem here is to correctly expose the trunk of the tree whilst not over exposing the sky.

The camera metered this scene with a shutter speed of 1/125 sec. This photograph was shot 1 stop under exposed. It gives the shot a nice dark feeling and the detail is still visible on the majority of the trunk. Even 1 stop under exposing this scene did not prevent the sky as showing as clipped highlights on the histogram. 

Nikon D4 f4 @ 1/180 sec ISO 800

1/2 stop under exposing the scene revealed more detail on the darker areas of the trunk and lighten the green leaves. More highlight clipping was apparent on the histogram. 

Nikon D4 f4 @ 1/125 sec ISO 800

At the metered setting the camera has produced a well exposed scene, however with more highlight clipping visible on the histogram. 

Nikon D4 f4 @ 1/90 sec ISO 800

1/2 stop over exposed produces a scene that has lost detail around the leaves at the very top of the frame due to the highlight clipping. 

Nikon D4 f4 @ 1/60 sec ISO 800

1 stop over exposed has created a large highlight clipped area, that has not only lost detail in the leaves but also in the branches. 

In this series of photographs the camera's sensor has created a well exposed scene and at 1/125 sec the photograph has a good balance of the dark tree trunk and light areas in the sky. 

The next two series of photographs are of the same subject but were taken using two different metering patterns. The first using Matrix and the second using spot metering. The subject I chose to demonstrate the different metering patterns was a statue of Sir Francis Drake in Tavistock Devon. As the grey statue was framed by a cloudy overcast sky I thought it would be the ideal subject. 

Nikon D4 f4 @ 1/500 sec ISO 100

1 stop under exposed using matrix metering, the lighter coloured clouds are causing the subject, which is a smaller part of the photograph to be too dark and under exposed. 

Nikon D4 f4 @ 1/125 sec ISO 

1 stop under exposed using spot metering. The camera has exposed the image according to the statue and ignoring the cloudy sky. The detail in statue is clear and well exposed and the formation of the clouds can still be seen in the sky.

Nikon D4 f4 @ 1/350 sec ISO 100

1/2 stop under exposed using matrix metering has slightly more detail visible on the statue, but is still too dark and under exposed. 

Nikon D4 f4 @ 1/90 sec ISO 100

1/2 stop under exposed using spot metering, an acceptable photograph and well exposed. 

Nikon D4 f4 @ 1/250 sec ISO 100

The metered setting of the camera using matrix metering. The camera has exposed the scene for the clouds causing the stature to appear too dark. 

Nikon D4 f4 @ 1/60 sec ISO 100

The metered setting of the camera using spot metering. The statue is bright and well exposed but large areas of the sky were showing as clipped highlights on the histogram, losing more detail than when using matrix metering. 

Nikon D4 f4 @ 1/180 sec ISO 100

1/2 stop over exposed using matrix metering, lighter clouds but the statue appears still to be too dark.

Nikon D4 f4 @ 1/45 sec ISO 

1/2 stop over exposed using spot metering, large areas of the sky show as clipped highlights losing all the detail within the clouds.

Nikon D4 f4 @ 1/125 sec ISO 100

1 stop over exposed using matrix metering, a much better exposed scene, more detail can now be seen on the statue. 

Nikon D4 f4 @ 1/30 ISO 100

1 stop over exposed using spot metering, all of the sky is now shown as clipped highlights and the statue is also over exposed. 

This series of photographs clearly demonstrate the advantages of using spot metering for this type of scene. It is interesting to note that the two photographs that represent the best exposed photograph, whether using matrix or spot metering both use a shutter speed of 1/125 sec. Using matrix metering, this was 1 stop over exposed, and spot metering 1 stop under exposed.

Light - Measuring exposure 1

Exercise: Measuring Exposure Part 1 (4-6 photographs)

For the first exercise in Light I was to produce 4-6 photographs which are deliberately lighter or darker than the average metered setting and give reasons why.  

The photographs for this exercise were taken in RAW format and have had minimal post production in Photoshop so as to demonstrate the necessary differences.  

Nikon D4 - f9 @ 1/160sec ISO 100

I operated the camera in the manual setting for this series of photographs and was set to matrix metering, which gave the settings above for the correct exposure, according to the cameras sensor.
The white of the toll house to the left of the image contrasts nicely with the darker area to the right of the image. 

When viewing the above image on the histogram there was clipping to the darker areas. 

Nikon D4 -f9 @ 1/125sec ISO 100

By reducing the shutter speed the shadows have lightened and the clipped area has been reduced, but still showed signs of being too dark. The white front to the house was showing to the extreme right of the histogram indicating that it was as bright as it could be before this area would show signs of being clipped.

This photograph demonstrates the dynamic range of the camera. With these settings the histogram showed an even graph with peaks to the left or the dark end of the histogram. By reducing the shutter speed I was able to lighten the darker areas of the photograph to show more detail, however the metered settings the camera suggested produced a good photograph bearing in mind the range of light to dark shown in the photograph. 

Nikon D4 -f4 @ 1/60sec ISO 100

This photograph was another tricky one for the camera's sensor to master. The range of dark to light is not immediately apparent when first viewing this photograph. At the selected aperture the camera suggested a shutter speed of 1/60 sec, the dark areas were correctly exposed however the 'Kawasaki' writing on the fuel tank and reflection on top of the fuel tank were blown out, indicated by the histogram. 

Nikon D4 - f4 @ 1/80sec ISO 100

By increasing the shutter speed I was able to reduce the highlight clipping. The darker areas were still within the histogram. If i had selected spot metering and used the area of the 'Kawasaki' name for the meter reading the photograph would have been far too dark. By using the method shown I was able to produce a satisfactorily exposured photograph. 

Nikon D4 f4 @ 1/200sec ISO 800

The majority of the photograph of this old barn was dark with plenty of shadows. The sky behind was quite stormy with dark clouds to the lower half of the sky and light clouds to the top. Using the metered shutter speed of 1/200sec the top lighter part of the sky was blown out and showed as such on the histogram. 

Nikon D4 f4 @ 1/500sec ISO 800

By reducing the shutter speed by 1 stop I was able to darker the clouds sufficiently to bring the highlights within the histogram, not only giving the sky a more menacing look but also bringing the whole photograph within the range of the histogram. 




The quality of the photographs produced by the D4 at the metered reading prove that the camera is well capable of taking good images in the majority of circumstances, however when the dynamic range is exceeded, is it then down to the photographer at the time of shooting to use his skill and judgement to determine the best exposure. Post production can assist in this area as well. 

Part 4 - Light

The meaning of the word photography comes from the greek word phos, photos - light and graphos - writing. Painting with light is often an expression photographers use. The very essence of photography is light, without it we don't have an image. 'Photography is the manipulation of light' (Light, science and magic, page 13). Therefore if can control the quality of the light we are well on the way to making a successful image. 

How do we measure the light?

All modern DSLR's have a selection of different metering modes. They all work to assist the photographer in obtaining the best exposure for whatever scene you are presented with. I have been using various models of Nikon cameras over the years, I currently use a D4 and D300. 

Nikon use three different metering modes:

Matrix - with this setting the camera meters a wide area of the frame and sets the exposure accordingly in relation to the distribution of brightness, colour, distance and composition.  

Centre weighted - Camera meters the entire frame but assigns greatest weight to the area in the centre 8mm of the frame within the viewfinder. 

Spot - Camera meters a circle of 3mm (approximately 2% of the frame) The circle is centred on the current focus point, making it possible to meter off centre subjects. 





The principle of metered exposure is that the area being measured are averaged and the exposure set via the shutter speed and aperture so that the result is a mid tone, or in other words half way between black and white. 

These metering methods work well on most occasions but when faced with situations in which the results may be lighter or darker than you expect there are two ways of altering the exposure. One is to switch the camera's metering from auto to manual, and the other is to use exposure compensation. The former is my preferred method. 

Reflection on assignment 3

The feedback on assignment 3 was a lot better than I expected, I was not at all confident when I submitted it, not only did it take longer than I expected to complete I still thought that the photographs were not up to the standard I had hoped for. 

However it would seem my tutor disagreed with what I had thought, his feedback was complementary on the majority of the images, as well as constructive as ever on the ones that didn't quite hit the mark. My partner keeps telling me that I'm far too critical of my own work, I would rather be like that, than the other way around!

Its been a hectic six weeks, as Ive moved house and been without my Apple Mac for a month while its been in storage, I'm now all set up in the new house and back online.....trying to make up time on part four.

Feedback assignment 3

Overall Comments

Rich, I can see you have worked hard on this assignment and it can be quite a challenge to produce a set of images that incorporate the various colour theories. To be honest it often depends on the theme, some photographers find it easier to work thematically and then struggle with an open brief. With this particular assignment there is an abstract feel to the majority of your shots, and the mix of locations helping to ground the images rather than distract from the overall feel. 

Feedback On Assignment

Complementary Colours – The first shot of the bus behind the hedge works well, at first glance the image does have an abstract feel, possibly due to the text on the back of the bus as it seems to disorientate the viewer, which I think works well.

Similarly with the shot of the floral display in Portugal where the light and colour of the curtains help to create a good background, the composition and small depth of field bring the image to life and we can see a definite style to both of these opening images.

The rusting boat provides good subject matter for the third image and although it is a more straightforward shot it combines well with the other photographs in this section.

Similar Colours – The shot here of the same boat works a lot better, there is more range in the colours and the cracks in the paint give the image a kind of mosaic feel. The shot of the shelter is one of my favourites from this assignment, the formal style of the image keeps all of the focus on the colours and to a lesser extent the actual design of the shelter. As with many of the images in this assignment, the shot highlights your observation and pre-visualisation skills really well.

The violet flower with the red background is an unusual image because it is very rare to see a combination of these colours; again this is down to your observation skills which do seem to have come to the fore in this assignment. The shot of the lemons also works well although I would have been tempted just to crop out a little to show the viewer more of the actual scene.

Colour Contrast – I can see what you trying with the shot of the narrowboats, but I think you need to get closer to them, the composition is little cluttered with the text on the boats being a little distracting too. We are naturally drawn to text within a photograph as it immediately satisfies our curiosity.

Interestingly the text in the following image actually becomes part of the image and it works really well. The reflection of the lady in the green/turquoise dress finishes the image off excellently because it draws the attention away from the text although not the actual colour which remains integral to the success of the image.

The shot of the balloon works to an extent but seems out of kilter with the rest of the images in terms of style, the evening light helps to keep all the colour elements quite compact, but possibly a longer focal length lens would have helped.

The image of the marina entrance building is a good architectural style of shot, the perspectives are all correct and this leaves the viewer to concentrate on the colours which again are quite rare in this combination. I would tend to replace the shot of the narrowboats with the one of the pallets as this one works a lot better.

Colour Accents – The shot of the childs coat (is it a costume?) is excellent and here we can see how a colour accent can add uncertainty to an image, the shot also asks many questions which the viewer has to unravel.

The sign on the wall reminds me of a similar William Eggelston shot, I’m not sure if you looked at his work, but here we can see how strange colour combinations can work in a photographic context. The shot of the warning sign on Dartmoor is a good spot, it is really quite a subliminal accent that does catch our attention but in a kind of exclamatory manner! 

Learning Log/Blog/Suggested Reading/Viewing/ Pointers For The Next Assignment

Your blog remains quite integral as to an insight into your own working methodology, although if you could bring other photographers work into your own research I think this would be helpful to the assessors when they come to grade your work.

The fourth assignment can be a good opportunity to test your creative and imaginative areas of photography, the success of which can often depend on the actual object that you use, and your resourcefulness. Have a look at a couple of my students’ assignments, where George used a piece of waste gas pipe and Leonie used a chair that she is very attached to.

http://george507927.wordpress.com/assignment-4-light/

https://leonie-broekstra.squarespace.com/blog/2013/7/22/photos-assignment-4

A couple of interesting blogs worth a look are: Alec Soth (a great photographer who also runs a photo book publishing compant):

http://www.littlebrownmushroom.com/blog/

And an interesting article on documentary photography that may help you in the final assignment.

http://www.bjp-online.com/british-journal-of-photography/feature/2285829/stranger-than-fiction-should-documentary-photographers-add-fiction-to-reality

And finally some shameless self promotion, here’s my blog which I recently started in preparation for my own photo zines and books.

http://petefdavies.wordpress.com/2013/08/25/who-what-where/