General Knowledge – Page 2

Shooting digital infrared – avoiding the obvious

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Infrared picture of a tree in a churchyard

Infrared photography used to be a firm favourite of the darkroom user in a days of film supremacy, but with the advent of digital photography the popularity of infrared capture died away somewhat. It didn’t disappear completely, as it didn’t take IR junkies long to realise that many digital cameras are also sensitive to IR light, and with an IR, or a deep red, filter in place a decent enough image could be captured. The number of digital cameras now that have sensitivity significantly extended into the IR wavelengths are few, as it actually has a detrimental impact on normal daylight photography, but some do still have enough ability to record IR light that an image can be made.

What is infrared?

Infrared is the name given to a group of light wavelengths that extend beyond visible red. The word ‘infrared’ means ‘below red’ in Latin – referring to the fact the wavelengths are longer than those of red. For creative photographic purposes the wavelengths we are interested in run between about 700 nanometres and 1000, but some forms of scientific applications use even longer wavelengths.
In IR photography we capture the infrared portion of the spectrum that is reflected from objects in the scene. In general terms live objects, such as grasses and leaves reflect most IR, and these objects appear very bright in IR images. It is commonly believed that IR photography captures differences in temperatures, or that certain objects emit IR light. Neither of these are true.

Fujifilm IS Pro

For this picture I used a fully infrared compatible camera – the Fujifilm IS Pro. This is a camera built into the body of the company’s S5 Pro DSLR, but with the infrared blocking filter removed, and with menu controls specific to shooting in IR. Originally designed for scientific work, it soon grabbed the attention of creative photographers as an extremely convenient way of recreating what they used to do with a tricky and complicated film process. The camera can shoot in colour as well as black and white, and with a ‘hot filter’ (which cuts out IR) over the lens it acts as a normal camera.

Is your camera IR sensitive?

An easy way to find out if your camera has sensitivity to light in the IR part of the spectrum is to cover the lens with an IR filter and then shine in IR light at it. Infrared filters are not cheap, but sources of IR light are common. A TV remote will work, and aimed in low light at your camera with the IR filter over the lens will record as a bright dot on the rear LCD screen when a button is pressed.
You can have your DSLR converted to shoot IR by having the IR blocking filter removed. Companies such as ACS will perform the surgery for you. Don’t try it yourself.

An infrared picture of Tower 42 with white clouds and a black sky

Avoiding the obvious

There is enough IR photography about for the effect to be easily recognisable, and most IR photographers do much the same thing. On a sunny day a blue sky records as a deep black, while clouds reflect large amounts of IR and appear bright and dramatic. Most photographers will try to use these characteristics to create a dramatic and impactful image. There is nothing wrong with that either, but I prefer to use the effects in a less obvious way that still creates an interesting picture, but one that does not scream ‘I’ve been shot in IR’.

IR film used to be very grainy, and could be used to create a coarse textured image that was very appealing. Here I’ve chosen a subject that suits that kind of treatment – an old building – and used the IR effect to have a mildly surreal impact on the grass and leaves to make the picture standout as being a bit different. The effect is very soft and almost dreamlike, without being obviously manipulated or part of a special process. I don’t want the first reaction to the picture to concern how it was done, but what it looks like.

There is no easy way to measure IR light with a normal exposure meter, so we end up having to guess. With film that could be a drama itself, but obviously with a digital IR camera life is much more straightforward – you can view the success of the exposure immediately. Generally small apertures are needed to ensure focus (IR light does not focus in the same plane as the light our cameras and lenses are designed for), and lengthy shutter speeds are needed to compensate.

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Fujifilm IS Pro f/11 @ 1/40sec – camera rated at ISO 100.

Infrared picture of a tree in a churchyard

Grass and leaves reflect IR and appear lighter in IR images

An infrared picture of Tower 42 with white clouds and a black sky

A blue sky turns black in IR photography, and clouds stand out with drama

Photographing street scenes – The right moment

Just as with wildlife photography it is the shots that show behaviour, rather than the pure record pictures, that work best in street photography. To show that behaviour clearly, so that the viewer can recognise what is going on, you have to pick your moment carefully. You have to show the moment in which the action happens.

Decisive moment?

This moment is often called ‘the decisive moment’, but the phrase is so over burdened with history and expectation that I prefer to just call it ‘the right moment’.

In this scene of a couple of office workers having a smoke break I spotted the potential from a way off, as the pair made an interesting shape that broke the pattern of the straight lines of the pillars and windows. As they had only just lit-up I knew I had a while to get the shot I wanted. I noticed the guy on the left had a particular way of blowing out his smoke in an over dramatic fashion. He turned his head, blowing the smoke away from his friend and in the process propelling it across the dark lines of the concrete. As the smoke got caught in the light of the overcast day it became illuminated, and created just the contrast I needed.

I shot a few frames to get a feel for the composition, and to watch the behaviour before everything lined up and I got the picture I wanted. Going back over those other frames, it’s obvious that it is the small detail of the smoke blowing that makes this moment stand out from the others. The alternative frames have the same pattern and the human shapes that break it, and they have the interest of two humans chatting. But they lack that extra something that separates the ordinary picture from the interesting.

Using a shallow depth of field

To help the subjects stand out from the background I used a really wide aperture to introduce a really shallow depth of field. Using a long lens helped too, as longer focal lengths make it easier to reduce the amount of the scene that is in focus. I was lucky that I had an exceptional lens – a 135mm f/1.4 which I was using on an APS-C sensor camera, so it was acting more like a 200mm. But even if you don’t have a long lens that’s not quite as ‘fast’ as this one you can still get the effect. A 200mm zoom will give a similar effect at f/4.5 on an APS-C camera.

Making the crop

The last thing I did to this picture was crop it to the 16×9 format. I did this for two reasons, firstly there is quite a bit of spare space at the top and bottom of the picture, as you can see from the full frame examples below. The second reason is that I love the movie feel this cropping ratio lends an image, and this picture suits that look. It could be a frame from a film, and the ratio of the format just enhances the sense of the moment.

Sony Alpha 700, 135mm f/1.4 ZA Carl Zeiss Sonnar T* lens, 1/2500sec at f/1.8 and ISO 400

Taken in Warsaw, Poland.

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Not quite the right moment

This one’s nearly there, but it could be more interesting

Ahh, that’s a bit better

White balance for atmosphere – Dubai friends

Recognise the importance of colour • Use ambient colour casts to demonstrate atmosphere • communicate emotions to your viewers

What we see and what the camera sees is not always the same thing. Our eyes adjust indoors to the yellow warmth of domestic light bulbs, so we hardly notice they’re light is not daylight, but film can only record what is there. Thus if you shoot with film indoors at night you get very yellow pictures.

Digital cameras have a way of compensating for the colour of different light sources, so you can take the yellow out of the tungsten bulbs in your dinning room, and the green out of the fluorescent strips under the kitchen cabinets. The light on an overcast day can have some warmth applied to compensate for its blue-ness, and there is even a custom setting that can be used to deal with the oddest coloured light you could come across.

White balance control is a brilliant thing, especially the custom setting, and is, I’d say, one of the best features digital photography has given us. Being able to record colours accurately under different light sources is a dream for professionals and amateurs alike.

There are times, though, when the colour of the light provides atmosphere, and we should not forget how important this is to us. We turn the lights down low, or light candles, to create a romantic atmosphere at home because we like the warmth of this kind of light. The blue haze of a cold day lets us know it’s cold before we’ve even gone outside, so removing the cast with white balance settings can actually produce a false idea of what the day was like.

In the shot shown here I wanted to keep all the colours of the street in the picture, as they are half of the attraction. In any case, no single setting could have compensated for such a wide range of light sources. I set the camera to the daylight setting – the one I use almost all the time – and let the colours live.

In the second example you can see what the shot would have looked like had I used the tungsten setting. The composition is still there, and there are hints of the warmth of the light, but the blues and greens have cooled the atmosphere too much, and I can’t feel the heat of the Dubai night any more.

Colours play a massive part in our life – we all have strong reactions to colours and we associate meanings to all of them. Would you drive a pink car, wear a bright blue shirt to a funeral or feel cosy in a fluorescent green room? Appreciate how much of a part colour plays in our responses and our emotions, and use it in your photography. Don’t automatically kill colour casts from artificial light, or that which is created by certain weather conditions unless colour accuracy is important to what you are trying to do. When atmosphere is important use those colours, so those who look at your pictures have double the chance of understanding what it was like to be there.

Nikon D80, 18-70mm f/3.5-4.5 set at about 70mm.
ISO 3200 1/20sec @ f/4.5

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Daylight white balance

Tungsten white balance

Patterns and shapes – Muzeum Techniki

This ship’s propeller really caught my eye as I walked around in Warsaw, Poland, as its curved form is surrounded by a mass of squares and triangles.

Much of Warsaw’s non-modern architecture is based on right angles and straight edged shapes with few curves or circles. Although I suppose I hadn’t really made a mental note of that fact, when I came across this object, that has no straight edges at all, I was quite struck with it. In taking the picture I wanted to get over the contrast between the roundness of the propeller and the sharp edges of the notice board next to it, plus the visually powerful squares of the walls behind it. It was only when I looked through the camera that I noticed the blocks of the car park and the lines painted on the floor. These were something of a visual bonus.

At the time I had a wideangle lens on the camera and this is what I made the first pictures on. Viewing them on screen I realized that I wasn’t getting across the strength of the squares, as being close enough to fill the frame was creating too dramatic a perspective, which in turn distracted from what I really wanted to show. Instead I fitted a more standard lens (in this case a 28mm on the APS-C camera). This meant I had to move further away, which helped me to include more of the ground and those lines, plus it flattened the perspective. Moving away also meant I would have to worry less about the lens distorting the brickwork into curves rather than those strong straight lines.

Keeping the camera absolutely level was essential for the graphic and purposeful image I wanted to create, and keeping a wide aperture would allow the propeller and the notice board to stand out from the background, while still retaining enough focus in the brickwork that the shapes could easily be seen. I didn’t have a tripod with me at the time, but I wished that I had. Although the shutter speed was short enough to hand-hold the camera without fear of camera shake, mounting on a tripod makes getting everything right-up and level so much easier. In the end I took about six pictures before I was satisfied that I’d got what I needed.

Fortunately the day was overcast, so the reduced contrast of the softer light allowed me to show the three dimensional shape of the propeller without burnt highlights or overly dark shadows. The soft contrast also helped to display all the fine detail in the stonework, the notice board and the car park.
Originally shot in colour, I converted the picture to black and white via a channels conversion, using a combination of green and red channels. The green channel gave me fine detail, while the influence of the red channel boosted the contrast of the scene a little.

I didn’t have to do too much else to the image, other than some minor curves adjustments and then some unsharp mask to finish. The exposure was already quite dark, which I think adds to the atmosphere. The place the picture was taken is quite hash and serious, so making a jolly picture would not have been appropriate.

Pentax K10D with 50mm manual focus lens, 1/80sec @ f/2 and ISO 400

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Forecast
Satellite

Converging verticals – what, how and fixes

Converging Verticals Eiffel Tower with guide lines When we look up at a tall building its sides slope inwards to form an inverted V shape. We are so used to seeing in this way that we hardly notice the effect while we are enjoying the view. When we take in the same scene in 2 dimensions, as we do when looking at a photograph, the experience is quite different and we do notice the convergence of the vertical aspects of the building.

If the effect is exaggerated, or at least very obvious, it lends a sense of height and drama to the picture, and we can appreciate a a split second just how tall that building is. However, if the effect is only moderate the building might look as though it is tilting backwards and in danger of falling over.

As with many photographic visual effects moderate applications simply look like mistakes, so we should avoid them at the shooting stage, or learn to correct them afterwards.

The way to avoid the problem is to hold the camera completely level when taking the picture, as it is the looking up angle of the camera that creates the effect. Unfortunately, keeping the camera level usually means that the top of the subject will be cut off. You can move backwards to alter your perspective, but in the majority of cases this is not an option as space is usually limited in architectural locations. In any case you’d have to move a long way for even a moderately tall structure

To see more of my pictures
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See a map of where this picture was taken