Exercise - Softening the light

2013.03.24.SofteningTheLight (1)
f/11  1/15  ISO-200



2013.03.24.SofteningTheLight (2)
f/11  1/8  ISO-200

The first image was taken with a naked tungsten light source, and the second with the use of an umbrella to diffuse the light.  Image (1) has larger, hard, dark shadows.  Softening the light with a diffuser, the shadows are reduced and are much lighter in tone.  The image with naked lighting shows hard contrast.  As well as lightening the shadows, the diffuser also lightens the highlights.  This is most evident on the two shells in the bottoms corners, with more colour, and the turtle in the top right of the frame.
I would say that in this instance, that the diffusion was an improvement.  However, in some circumstances a hard contrast may be part of the desired effect.

Exercise - Higher and lower sensitivity

 

Exercise - Higher and lower sensitivity

Surrey Street Market (1)
f/13  1/40  ISO-100

Surrey Street Market (2)
f/18  1/60  ISO-400

Surrey Street Market (3)
f/11  1/40  ISO-100

Surrey Street Market (4)
f/18  1/60  ISO-800

Surrey Street Market (5)
f/13  1/40  ISO-100

Surrey Street Market (6)
f/22  1/60  ISO-800

Surrey Street Market (7)
f/18  1/25  ISO-100

Surrey Street Market (8)
f/22  1/50  ISO-400

Surrey Street Market (9)
f/14  1/30  ISO-100

Surrey Street Market (10)
f/20  1/60  ISO-800 

Surrey Street Market (11)
f/13  1/40  ISO-100

Surrey Street Market (12)
f/18  1/80  ISO-800

Surrey Street Market (13)
f/14  1/40  ISO-100

Surrey Street Market (14)
f/18  1/80  ISO-400

I took these photos with the intention of achieving a similar exposure at an ISO of 100 and then at 400 / 800.  Reviewing the photos now, the second shots at ISO-400/800 are noticably lighter than the similar shots taken at ISO-100, particularly in the shadow areas.
In hindsight, I got a bit carried away with the situation, enjoying shooting the scenes below my high viewpoint.  It would have been better for this exercise to take more marginal / extreme shots, at the highest shutter speed or aperture possible.  Increasing all images on screen to 100% there was little noise on any of the photographs.  Obviously, with more marginal shots a clear difference would be apparent between the low and higher ISO images.  Increasing the image sizes further, the higher ISO photos retained their quality to a large size, but this was marginal due to minimal noise on all images. 
What was very clear after taking a photo at ISO-400 or 800, and then changing the ISO to 100, was how the screen or viewfinder was thrown into darkness.  Vice versa, increasing the ISO meant that the shutter speed and aperture could be increased for the next photo, with greater light available.
Changing the ISO from 100 to 400 increases the cameras sensitivity to light by four times.  In this series of photos, the aperture has been around mid-range.  Looking at the shutter speeds though, you can see that they are relatively low through the shots at ISO-100.  There would not have been much scope to increase the shutter speed without then compromising on the depth of field, by selecting a low aperture.  At ISO 400, it is possible to increase the shutter speed by four times, or reduce the aperture by four times.
Up until doing this exercise, I have got into the habit of setting the ISO to auto.  Now that I have a greater understanding of its function, and the extra control it allows, I will now set the ISO manually.

Exercise - Measuring Exposure

Part One -

Dark

Dark - Clearing
f/22  1/320  ISO-3200

This was taken not long before sunset, with the sun low and to the left of the frame. While parts of the frame are actually light, much of it is in shade so there is a contrast between light and dark areas.  I think you do get a sense of fading light from the image.  This is what I wanted to convey, and for this reason did not lighten the shadowed areas.

Dark - Mask
f/4.5  1/15  ISO-3200

 The light source, a window, is about 15ft from the subject which itself is dark,as is the background.  In fact, there was just enough light to take the photo.  I could have used flash but this would have lit the eyes and shown the background behind them.  There is a certain darkness about the mask, and not just in colouration.  I wanted to capture this, by limiting the colour and seeing the eyes filled by dark shadow.

Light

Light - Sculpture
f/5.6  1/8  ISO-400

 The subject was positioned on a shelf.  I directed the flash on to the shelf above, so the light would bounce off it, back down on to the sculpture and also light the background.  The light feel to the image and background creates a contrast to the apparently anguished pose of the figure.

Light - Surrey Hills
f/22  1/400  ISO-3200

A darker exposure would have given a higher contrast between the lighter green areas and the slight red colouration.  However, I liked the subtle blend of tones and softness created with this fairly light exposure.

Part Two

I generally aim for slight under exposure, on the basis that alterations can easily be made later.  If an image is over exposed, darkening it post production can be quite ineffective.  Each of the series of photos in part two of the exercise were set around the "best exposure" being -1 (slightly darker than average) on the exposure scale. 

Dried Sea Urchin (1)
f/14  1/100  ISO-100  ISO 3200

Sea Urchin (2)
f/13  1/80  ISO-3200

Sea Urchin (3)
f/11  1/80  ISO-3200

Sea Urchin (4)
f/10  1/60  ISO-3200

Sea Urchin (5)
f/10 1/50  ISO-3200

In the Sea Urchin photos, I found the shots half a stop lighter or darker to be acceptable.  The central exposure was much what I expected, perhaps lightly brighter in some areas.  The lightest image had too bright a reflection on the surface, and the darkest seemed a bit flat.

Garden Framed (1)
f/14  1/100  ISO-3200

Garden Framed (2)
f/14  1/60  ISO-3200

Garden Framed (3)
f/14  1/50  ISO-3200

Garden Framed (4)
f/14  1/30  ISO-3200

Garden Framed (5)
f/13  1/25  ISO-3200

The central exposure in the Garden Framed series was a little darker than expected. I put this down to standing under dim lighting, with brighter light behind the window frame.  The darkest shot was not appealing.  I found all of the others acceptable, although actually preferred the shots half a stop and 1 stop lighter.   These gave the window frame a whiter appearance and are more balanced.  The photos were taken through the glass of a kitchen door leading on to the sun lounge, with the window frame opposite.  

Green Candle Bottle (1)
f/22  1/25  ISO-3200

Green Candle Bottle (2)
f/20  1/20  ISO-3200

Green Candle Bottle (3)
f/20  1/15  ISO-3200

Green Candle Bottle (4)
f/18  1/13  ISO-3200

Green Candle Bottle (5)
f/18  1/10  ISO-3200

The central exposure of Green Candle Bottle is a touch darker than expected.  The two darker exposures don't work for me, and I find the lighter two work best.  The darker exposures lose any warmth from the green and yellow colouring.  I used natural light, but on reflection bounce flash would probably have worked better.

Tree Statuette (1)
f/18  1/25  ISO-3200

Tree Statuette (2)
f/14  1/25  ISO-3200

Tree Statuette (3)
f/11  1/25  ISO-3200

Tree Statuette (4)
f/9  1/25  ISO-3200

Tree Statuette (5)
f/9  1/15  ISO-2500

The central exposure of Tree Statuette is as expected.  I think all of the other images work, apart from the darkest exposure.  Image (4), half a stop lighter, is the photo I would pick, with the lightest picture second choice.  

Weathered Door (1)
f/22  1/25  ISO-3200



Weathered Door (2)
f/18  1/25  ISO-3200

Weathered Door (3)
f/16  1/24  ISO-3200

Weathered Door (4)
f/13  1/25  ISO-3200

Weathered Door (5)
f/10  1/25  ISO-2500

The Weathered Door images were taken in fading light, under cloudy conditions.  I think there is potential for a more satisfying image in bright sunlight, towards the end of the day.  The central exposure is as expected.  However, I do prefer the lighter images.  The exposure half a stop darker is OK but one stop darker is too dark.