Art of Photography

Rob Townsend


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Exercise – Higher and lower sensitivity

Brief:

Take similar shots at both normal and high sensitivity (ISO). Shoot first at normal sensitivity, then change to higher sensitivity. Note whether the change make shooting easier. In particular, note whether there were photographs that you could not take successfully at the lower sensitivity but were possible at the higher setting.

Results:

1. Berries:

Berries ISO 200

Berries ISO 200

Berries ISO 800

Berries ISO 800

Shooting handheld, trying to get a sharp shot of these berries at ISO 200 proved to be a bit difficult. The ISO 800 shot looks sharper, without too much noise evident.

2. Hat:

Hat ISO 100

Hat ISO 100

Hat ISO 800

Hat ISO 800

The weave of the hat is much more evident in the higher ISO version. However, looking at the background there is a fair amount of noise visible.

3. Stall:

Stall ISO 200

Stall ISO 200

Stall ISO 800

Stall ISO 800

In this street shot where there was a fair amount of movement, the low ISO shot gave far too much blur. Increasing to ISO 800 allowed the faces to be in focus. A little noise is creeping in, but the higher ISO shot is clearly a sharper capture.

4. Dalek:

Dalek ISO 100

Dalek ISO 100

Dalek ISO 3200

Dalek ISO 3200

For the remaining shots I tried to see how low and high ISO coped with decreasing light. This particular shot was taken at night, through the window of a vintage car showroom that for some bizarre reason has a dalek on display. The ISO 100 shot looks OK at a small size but when you zoom in to 100% the blur is visible. In this instance I went for an extreme change in ISO, right up to 3200. The effect is clear: the higher ISO allowed a much quicker shutter speed and less movement blur. However, the noise is heavy enough to spoil the shot. In a real shooting situation the best compromise might have been been in the ISO 800 – 1600 range.

5. Station:

Station ISO 100

Station ISO 100

Station ISO 1600

Station ISO 1600

Early evening outside a train station, and even though there was some ambient street lighting, the ISO 100 shot is blurry; the aperture was as wide as possible but the shutter speed was too slow to freeze any motion. The ISO 1600 version allows for a quicker and therefore a slightly sharper capture – but the shadows are looking fairly noisy. Overall, the higher ISO shot is more acceptable.

6. Road:

Road ISO 100

Road ISO 100

Road ISO 3200

Road ISO 3200

Probably the darkest scene I shot, and again I chose quite extreme low and high ISO settings. At ISO 100 the scene is far too blurry, even when viewed small. By cranking it up to ISO 3200 it’s possible to clearly make out the text on the diversion sign, although the flat surfaces – the sky, the road – are extremely speckled.

What I’ve learned:

Another eye-opener of an exercise. Up until now I’ve tended to try to stick to low ISO as I know that this will, in the right light circumstances, give the best quality image. What this exercise has brought home is that in the right circumstances it can be advisable to increase the ISO to make best use of low light and/or to allow faster shutter speed. Interestingly, I had to increase the ISO quite a bit on some of these to demonstrate (exaggerate) the effect. I believe modern digital cameras are better able to cope with reducing noise at higher ISOs. I do now have a better appreciation of how ISO can be used in marginal situations to achieve the desired exposure. Going forward I think I’ll probably treat it as a third option for adjustment, if I can’t achieve the desired effect by adjusting shutter speed and aperture.


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Exercise – Measuring exposure

Brief:

Part 1: produce between four and six photographs which are deliberately lighter or darker than average, and say why in your written notes.

Part 2: take five or six different photographs, of any subject, but for each one make five exposures, arranged around what you have measured as the best exposure.

Results:

Part 1:

Sunset

I wanted to intensify the colour of the sunset sky and achieve a silhouette effect with the tree, whilst still maintaining some detail in the foreground. Underexposing by 1.0 EV gave the effect I wanted.

Sunset -1.0 EV

Sunset -1.0 EV

Scooter

I took this around the middle of the day when the sun was high in the sky and the colours tended to look a little washed out at the supposed ‘right’ exposure. I pushed the exposure down by 1.0 EV to make sure the black of the scooter came out representative of the actual shade.

Scooter -1.0 EV

Scooter -1.0 EV

Portrait

I wanted to get half of the face invisible in the dark shade and the other half faintly visible… I was going for a spooky/moody effect. To get the look I wanted, I dialled in -1.3 EV compensation.

Portrait -1.3 EV

Portrait -1.33 EV

Bottles

This is the one example where I deliberately over- rather than underexposed. I was aiming to get the white of the bottles to almost fade into the white background, for a cool and minimalist aesthetic.

Bottles +2.0 EV

Bottles +2.0 EV

Part 2:

In this part I used a range of exposures from -0.67 EV to +0.67 EV, as my camera only does one-third stop exposure compensation and not half-stop compensation as suggested in the exercise brief.

Alley

In this set I believe the first two (underexposed) look most natural, and the remaining three look too bright to my eyes. My preference would be for the darkest, the -0.67 EV version.

Berries

Here I think the middle three all look acceptable. The -0.67 EV version is starting to get a little too dark in the shaded parts of the image to see the details, and similarly the +0.67 EV overexposure is starting to blow out the whites. If I had to choose the most pleasing version, I’d go for the slightly underexposed -0.33 EV image.

Cafe

On this grey and overcast morning I actually found most of these a little too dark, up to and including the supposed ‘best’ exposure at 0 EV. In the two overexposed shots you can finally get to see some of the detail in the brickwork that is otherwise hard to make out. My preference is for the +0.33 EV version, as the +0.67 EV version starts to make the sky a little too bright.

Castle

Here I think the 0 EV and the +0.33 EV work best, with a marginal preference for the latter. In the underexposed shots the detail of the castle walls is getting lost, which would be OK if you were going for a silhouette look (in fact you’d underexpose even more).

Fire

In this final set I preferred the two underexposed images, as from 0 EV onwards I see the image tending towards being overly bright in the light areas.

What I’ve learned:

This was a fascinating exercise. I’ve realised now not to rely on what the camera believes is the ‘correct’ exposure as often the effect you want to achieve is significantly different (as in part 1) or in fact the camera just makes the wrong call, or at least different to the one I’d have made (as in part 2). As I shoot predominantly in RAW these days, I do think I can give myself a certain amount of leeway for adjusting exposure after the event, but in the main I do aim to get it right in camera. Now I will think more about what type of image I want to produce and what decisions I need to make on under- or overexposure that will help me achieve the previsualised aim.


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Exercise – Control the strength of a colour

Brief:

Find a strong, definite colour and choose a viewpoint so that the colour fills the viewfinder frame. Find the average exposure setting. Then take a sequence of pictures; all composed exactly the same, but differently exposed from bright to dark by adjusting the aperture setting.

Equipment:

Canon EOS 650D with EF 18-200mm f/3.5 lens.

Results:

I chose a red scatter cushion against red upholstery. The over-exposed shots, especially the +1.0EV, render the red rather bright, almost pink-like. As the exposure was changed the colour became more saturated, as expected. Also, in the under-exposed shots the detail and texture in the material becomes more visible. In my opinion the slightly under-exposed one (–0.5EV) most closely matched how my eyes saw the colour in real life, which goes to show that the camera’s metering isn’t always perfect.

1/20s at f4.0

1/20s at f4.0 (+1.0EV)

1/20s at f4.5

1/20s at f4.5 (+0.5EV)

1/20s at f5.6

1/20s at f5.6 (0.0EV)

1/20s at f6.7

1/20s at f6.7 (–0.5EV)

1/20s at f8.0

1/20s at f8.0 (–1.0EV)

What I’ve learned:

It’s possible to control the strength of a colour through a deliberate choice of exposure. This is something I’ve usually left to post-processing, often boosting saturation if I think the camera didn’t quite catch the colours well enough. What this exercise has taught me is that to a certain extent I can actually do this in camera. Very interesting.