Higher and lower sensitivity

The objective of this exercise was to take similar shots at different ISO sensitivities and comparing the results, so I set myself up with a tripod by Derwent Water on an overcast day.  I shot between ISO 100 and 3200, but cannot see any real differences in graininess, and due to the tripod, all shots were possible.  I decided to repeat the experiment hand hold in a market place as the instructions recommend!

Second attempt shot in Borough Market taking advantage of the situation to try out my new prime lens (faster aperture so should perform better in darker conditions).  My aperture was fixed at f/1.8 as I wanted to create blurred backgrounds and foregrounds and I allowed the shutter speed to adjust automatically I moved through the ISO settings.

ISO 100

1/90s

At ISO 100 the shot is perfectly clear.  The exposure is aided by the lighting of the market stall.  As the shutter speed at this ISO at aperture is fairly slow, I would think that with greater depth of field, the shot may not have been possible at ISO 100.  A close up shows that there is no graininess in the photo but a narrower aperture would have given greater clarity in the shot.

ISO 200

The next image was taken outside the main market using a faster shutter speed.  The smell coming from that stand was amazing!  I could have used a more narrow aperture for this shot, but with the faster shutter speed there picture is quite clear. 

1/500s

A close up reveals that there is still no graininess.

ISO 320

My camera is capable of ISO 250, but I wasn't expecting a huge difference, so my next shot was taken at ISO 320.  Indoors again and back to slower shutter speed.

1/90s

An close up shows that a small amount of graininess is already creeping in.  It's particularly visible on the block purple barrier sheets.  This has surprised me - I wasn't expecting it to show at this ISO.  So now I know!  If I want to take an image that I intend to crop and enlarge, I need ISO 100 or 200.

ISO 400

Darker conditions, but a higher ISO affords a faster shutter speed: delicious paella!

1/250s

And as now expected, the close up shows that noise is present.

ISO 500

Continuing to move up through the ISO settings and although dark, I can use a fast shutter speed, or I could have narrowed the aperture.

1/500s

Examining the close up, there doesn't seem to be too much grain, although if I zoom in on the wooden branch, it's quite visible.  So grain seems to be more obvious with flat colours.

ISO 640

A visit to the mushroom stand, conditions seem to be darker here, so depsite the higher ISO, a slower shutter speed is required.  At this resolution, grain is still not visible.

1/250s

But, the enlargement clearly shows gain, as now expected.

ISO 800

Delighted to find some Cumberland produce, and particularly Herdwick lamb, brighter conditions and a higher ISO afforded a faster shutter speed again.

1/500s

 An enlarged extract shows that grain is ever presen, but it doesn't seem to be getting any worse.

ISO 1000

Now at the levels where I was personally expecting grain to start appearing.  I think there would have been a good shot here if I'd taken more time - I liked the colours and tones in this image.  Dull conditions, but the higher ISO is affording a faster shutter speed.

1/750s

The enlarged extract shows the grain quite clearly - particularly on the transparent counter casing.

ISO 1250

I've never ventured this far up the ISO settings so I was curious to see what the results would be.  I couldn't resist this shot of the jacket that matched the hanging chilli peppers in both colour and the form of the quilting!  It was quite dark in this outlet, so as expected, the shutter speed is lower.

1/350s

You still can't really see grain in a normal view, but the enlarged close up reveals that it is actually now getting worse!

ISO 1600

Back in the street - the longest queue of all the outlets was for the coffee shop.  People need coffee more than food!  This shot has quite difficult lighting to resolve - the daylight of the street, the darkness of the interior of the shop and the glow of the lamps.  You can see that the people's faces are overexposed, and also not particularly clear.  The camera set to a very fast shutter speed at this ISO, so if I was attempting this shot for real, I probably would have widened the aperture and perhaps tried the different metering options.

1/1500s

And as expected, the shot is grainy when cropped and enlarged.

ISO 2000

Again - difficult light to resolve and completely the wrong exposure for the conditions!  Now on a very high shutter speed, but faces are still over exposed.

1/3000s

The close up is now very grainy!

ISO 2500

I like the depth of field (or lack of it) in this shot of the olive stand.   Darker conditions, so a slower shutter speed than the shot above, despite the higher ISO, but still relatively fast.  So if grain was not an issue, you could use the high ISO to get the clarity afforded by fast shutter speeds - or to give greater depth of field.  I think grain here is starting to show at this resolution.

1/1500s

An enlarged extract now reveals quite a bit of noise - particularly in the blurred foreground.

ISO 3200

Last one of this series, although my camera does have higher settings still; some people enjoying a coffee.  The shutter speed has decreased here - not sure why as the light was better than by the olive stand...Again the exposure isn't really working very well - there is too much reflection of the skin.

1/1000s

The enlarged extract shows even more grain than previous images.

How is this useful?

Apart from knowing to keep the ISO as low as possible, to avoid noise, it could also be used the other way round to deliberately create noise.  At the Wildlife Photographer of the Year exhibition one year, I remember seeing a shot of a grass plain with giraffe running across; it was shot in bright sunlight on a very high ISO to deliberately add grain, it was also deliberately blurred and produced in b&w.  A very effective image.

I took this image at 1EV over 3200 (what does that mean??) - the grain is visible now at normal resolution.

And changed it to this!  It resembles a photo taken by a private investigator!

Assignment Three - Colour - Corrections

Here are my corrections to Assignment Three following my tutor's feedback and some rethinking:

Similar Colours:

The purple and green image that I used did not really fulfill the "similar" criteria, so this will be substituted for blue and grey:

The shot of the moth also didn't work very well; this was a subjective decision to include this one.  It will be replaced instead by this picture of yellow and shades of brown in an owl butterfly; the picture would have been better if I hadn't clipped the top of one of the antennae, but it illustrates the colour point:

Green and Blue - my original was a wide shot of the lake, in which it was recommended that I reduce the brightness of the boat, however, I have since captured a much better image of green and blue, so I will use this one instead:

Contrasting Colours:

Orange, Purple and Green - reduce the red to see if it brings more attention to the blue (which worked nicely!):

Red and Blue: the image of the power station wasn't helped by the gas tank placed behind it.  This picture might be representation of contrasting blue and red:

Orange and Green - my tutor commented that the colours are fairly similar because they melt in to each other so smoothly but there is some contrast with the darker green background.  I have chosen not to make any corrections here.

Colour Accent:

Red danger sign accent - desaturate the other red shape a bit so that it doesn't compete with the sign:

Purple accent - this shot didn't work - the accent wasn't strong enough.  I have reshot using a yellow accent against purple:

Yellow accent - O2 - Snip a bit off the lower edge of the frame to make the speed boat more noticeable and balance the composition a bit better: 

K.

Measuring exposure

The first part of the exercise required between four and six photographs which are deliberately lighter or darker than average and to say why (I took eight in the end that I have used - I enjoyed this exercise!).  On the day that I shot these photos, the lighting was very dark with snow filled clouds blocking out most of the light to the point that there was no shadow effect.  With snow on the ground and the same colour as the sky, this gave me a useful opportunity to investigate whether it was better to over expose snow (as I had previously heard was the right thing to do) or underexpose.  As I found, it depended on whether I wanted to brighten up the image to make the scene lighter, or to darken it and make it more gloomy.  As the light was so awful, my ISO was set to 800 for the whole day to give me faster shutter speeds.

My first picture is the view across the common near my house in Feltham with the Young Offenders' Institute visible on the horizon: I deliberately underexposed this shot to make the scene darker and more gloomy than it really was on the day.  You can see the weight of the snow clouds hanging over the Institute.  This was shot with a wide-angled lens at 24 mm, ISO 800, 1/1000s, f-9.5, making it -1.0EV.

My second shot was taken roughly from the same place, but this time looking back towards the estate where I live.  I wanted to make this shot look a bit brighter than it was on the day to make the brick work stand out against the sky.  I couldn't make it too bright as that would have over-exposed the snow, at this exposure, you can see the difference between the snow on the roofs and the sky.  This was shot with a wide-angled lens at 24 mm, ISO 800, 1/350s, f-9.5, making it +0.5EV.

My third shot was taken again, roughly from the same place, but this time looking west towards the airport.  I wanted to capture detail in the snow, so I overexposed this shot more than the previous one and excluded much of the sky to reduce the light coming in. Again, this was shot with a wide-angled lens at 24 mm, ISO 800, 1/180s, f-9.5, making it +1.0EV.

The next picture was taken looking into a timber yard.  The challenge here was how to cope with the dark wood in the dark lighting conditions.  I wanted to brighten up the wood without brightening up the snow too much and risk losing definition of the roofs against the sky (there was some brightness in the sky in this direction).  Still using a wide-angle lens at ISO 800 and f/9.5, but with a focal length of 10mm and 1/350s, the result was +0.5EV.  You can see some definition in the wood and snow but without too much brightness.

My fifth picture included some colour.  This was taken at the front entrance of the Young Offender's Institute.  The red stands out against the bland surroundings however, I found that I had to over expose the image to make the red close to the original.  Again with a wide-angled lens at ISO 800 and 10mm focal length, f/9.5 and 1/180s.  The shot was +0.5EV.

More colour: in my sixth picture, I found some bright green against the snow and grey sky.  I found I had to over expose this more than the previous one to get the green close to its real life colour.  This also gave me some more definition in the snow on the bridge.  Still with a wide-angled lens at ISO 800 and 11mm focal length, f/9.5 and 1/180s.  The shot was +1.0EV.

I then headed off into London for the afternoon.  Unfortunatley, by the time I got there, the light was so awful everything needed brightening up, so I opted for an indoor experiment in the Tate Modern.  This part of the building was quite dark, but with bright light interacting.  The challenge here was to get enough light to capture the scene and reflections, without blowing out the lights themselves.  I had to drop my aperture from f/9.5 to f6/7 in order to get some shutter speed that I could handle hand-held.  I didn't want to widen the aperture any further as I wanted to keep the detail in the distance.  The image is slightly blurred as you would expect.  I took this at ISO 800, 24 mm focal length (wide-angled), f/6.7 and 1/8s making it +0.5EV.

My final image of the day for this part of the exercise was taken with a prime lens (the first one I have used from this lens!).  This is a faster lens than my wide-angled lens so it copes better with darker surroundings.  I stumbled across this busker in a tunnel along the South Bank; the tunnel was quite bright with the high lights, and knowing that my lens would cope well with the light, I underexposed the image as I didn't want those lights to be completely blown out. I am pleased with the blur of the cellist's hand and the retention of some of the detail of all the dark clothing, but I would like to have another go at this with a tripod, a wider aperture and a slower shutter speed.  This was shot at ISO 800, with a 35mm focal length, f/6.7, 1/45s, making the shot -0.5EV.

The second part of the exercise required photographing a subject several times at different exposures in order to determine which is the best exposure.  I decided to fix the ISO and aperture, as I was photographing landscapes and wanted to keep the detail in the background, and so varied shutter speed to vary the exposure. All the images shot here were using Matrix metering (Nikon).

1.  Mountain at the end of my street

This is a view that I'm deeply attached to; on a clear day it's amazing.  Unfortunately today was not particulary clear and there was a bit of white-out where the horizon meets the sky with the snow.

ISO 800 1/250s f/13

This is the average exposure, which on a bright day would have been fine.  Here it seems a little gloomy and despite the more narrow aperture, the detail of the mountain is lost. 

ISO 800 1/350s f/13

A slightly faster shutter speed, and the sky is loking a bit better with a bit more detail in the horizon; the street however is looking a bit more gloomy.

ISO 800 1/500s f/13

Shutter speed faster still and the sky looking even better with more definition between the horizon and the sky; however the street view hasn't worked at all.

ISO 800 1/180s f/13

At the slightly slower shutter speed, the picture is improving; although detail of the horizon is becoming lost, the scene is becoming more solid.

ISO 800 1/125s f/13

This is probably the photograph that works the best in these conditions; although there is less detail in the background with the mountains and the sky, the detail of the street is visible, and the mind understands that the background is snowy and so detail is lost.

 Therefore, this shot of a dark foreground and a brighter background, has worked better being one stop overexposed in order to retain the detail of the foreground.  This however relies on the audience accepting that some of the detail of the background is lost.  Ideally this is a photograph which works better on a bright day in which there is less tension between foreground and background.

2. Derwent Water

ISO 800 1/750s f/13

This is the average photograph, with less issues to resolve than the previous.  At the time of shooting this I was lucky that the light was good.  There is nice shadow in the foreground and good detail of the the treetops and mountain tops.

ISO 800 1/1000s f/13

At half a stop underexposed, the scene improves; the dark bits are slightly darker but the detail is still retained. 

ISO 800 1/1500s f/13

Half a stop again underexposed, and there is more detail in the sky but detail in the fore and mid-ground still retained.

ISO 800 1/500s f/13

ISO 800 1/350s f/13

Half a stop over exposed and the photogrpah has become weaker; there is less definition in the snow and horizon.

 

Half a stop over exposed again, and the photogrpah has become weaker; there is even less definition in the snow and horizon and the whole scene is looking a bit washed out.

In this case, because of the good light, the balance of snow and water, the scene worked better being underexposed.

3.  Derwent Ducks

ISO 800 1/180s f/13

With this scene, I thought the dark foreground and bright background, like the street scene above, would be difficult to resolve.  In particular I wanted the ducks to stand out against the grey paving.  This is the average exposure although the foreground has worked quite well, the clouds in the background are a bit overblown.

ISO 800 1/250s f/13

At half a stop under exposed, with a slightly faster shutter speed, the detail of the sky becomes clearer and less blwon out, while the detail in the foreground is retained.  The dark patches in the car and the jetty are becoming a bit dark though so I wouldn't want to under expose any further.

ISO 800 1/350s f/13

Even better sky, but some detail now in the foreground, particularly around the cars and trees is lost.

ISO 800 1/125s f/13

Half a stop over exposed and the picture is not good; the sky is now blown out.

ISO 800 1/90s f/13

At one stop over exposed, the sky is even further blown out.

In this case, the image that worked the best was the one that was half a stop under exposed; this shot managed to add definition to the sky without taking away detail from the foreground.

4.  Castle Crag from Friars Crag

I love this view: Castle Crag is the small pyramid shape hill in the centre of the horizon.  It qualifies as a Wainright, but does not meet the requirements necessary to be classified as a mountain (although when you climb it it is exhausting!).  It is also partly man made from the spoils of slate mining.  The views from this dimunitive summit along the Borrowdale Valley are spectacular!

ISO 800 1/2000s f/13

ISO 800 1/3000s f/13

This is the average exposure; I think it works quite well; there is sufficient detail in the horizon and the clouds look fairly menacing, although there is a blown out patch in the sky towards the left.

ISO 800 1/4000s f/13

ISO 800 1/1500s f/13

ISO 800 1/1000s f/13

As above, but the sky is slightly more menacing!










As above, but an even more menacing sky!










In the underexposed range, the sky is not as effective.








As above, and even less effective.

With this scene, I like the underexposed images the best.  In the image that is one stop underexposed, the scenery and sky is the most dramatic.  This is helped by the monochrome aspects and tonal range that the underexposure exaggarates.

5.  Tree Roots

There are some trees along the shores of Derwent Water with the most incredible roots; in Winter the trees look like they are double ended!  In these shots, the challenge was to retain the details and contrast of the shadows caused by the roots.  I used a polariser for these images.

ISO 800 1/180s f/13

Average exposure: this is the image that works the best.  The shadows and dark patches between the roots are visible, without losing too much detail.

ISO 800 1/250s f/13

The half a stop under exposed and the image is starting to not work well; the dark patches are a bit too dark.

ISO 800 1/350s f/13

 Half a stop again, and the image is too underexposed.

ISO 800 1/125s f/13

Half a stop over exposed and the image is starting to look a bit bleached.

ISO 800 1/90s f/13

A full stop overexposed and the image is too bright.

6.  Old Tree

I have photographed this tree before on a very bright sunny winter day, and I got a fantastic result with a polariser, however, I didn't compose the shot very well and chopped off some of the branches.  I was careful this time to make sure all the tips were tucked in!  Unfortunately the sky was not so stunning on this occasion.

ISO 800 1/500s f/13

ISO 800 1/750s f/13

Average exposure; image is adequately exposed with sufficient detail in the sky and darker patches.

ISO 800 1/1000s f/13

ISO 800 1/350s f/13

ISO 800 1/250s f/13

Half a stop under exposed; sky is improved but detail is lost in the horizon and foreground.











As above, but more exaggarated.












Half a stop overexposed; more detail in the foliage is picked up.











A full stop overexposed and some bleaching is starting to occur.

It's hard to say which exposure has worked the best; I think that ultimately the average exposure has as it is the only image with the correct balance between the sky and the darker patches.

7.  Keswick Market

I took an extra round of photos for this exercise, as I wanted to try a crowded street scene as well as the traditional landscapes.  The challenge here was to balance the sky with the darker detail of the market stalls.  At this stage, I used a wider aperture as the light was darker than it had been earlier and so I wanted to retain the shutter speed at the brighter exposures.

ISO 800 1/500s f/11

Average exposure: sufficient detail in the market stalls but the sky is a bit bright.

ISO 800 1/750s f/11

The detail of the sky is improving, but the detail in the market stalls is now too dark.

ISO 800 1/1000s f/11

Even better sky detail, but definately too dark now in the foreground.

ISO 800 1/350s f/11

Good foreground detail but sky starting to look blown out now.

ISO 800 1/250s f/11

Even better foreground detail but sky now completely blown out.










For this set of images, the problem hasn't been resolved.  The sky is best in the shot that is one stop under exposed, and the foreground is better in the shot that is one stop over exposed.  So to take such an image on this day, perhaps several images would have had to have been superimposed (HDR?) - but this would have presented a problem with people walking in and out of the frame. Perhaps using an N-Grad filter to darken the sky and then over exposing would have worked?

All in all, under, average or over exposure depends on the conditions and subject.  Skies respond well to under exposure and detailed foregrounds seem to respond to over exposure.