David Bennett

If you are a photographer then, like me, you may have been put off attempting close-up photography because of the difficulty of getting sharp focus from the front to the back of the object you are photographing.

Sometimes it is desirable to have part of the object out of focus, but what do you do if you want to photograph a fly or a bee and have its head and its back legs all in focus?

Depth of Field
Depth of field as used in photography refers to how much from the front to the back of a scene is in acceptable focus. The scene further behind and nearer than what is in focus is, of course, out of focus and blurred.

We expect some things to be blurred and the way our brains are wired, we expect that blurring to show in a particular way. Because of the way we perceive reality we expect – for example – a tree in the foreground to be sharp and hills in the far distance to be out of focus.

In fact, if we saw a photograph with the tree in the foreground in focus and the hills in the distance also in focus, we would think the scene looked artificial. This is precisely because it breaks our internal rules about what should be in focus and what should not.

The nearer we get (or the camera gets) to an object, the smaller the depth of field. In other words the front-to-back distance of what is in focus, is very small. We see this when we hold a book open in front of us with the page at an oblique angle. Some of the print is in focus, but some that is only a few inches nearer or further away is not in focus.

One thing about the way our brains work though, is that with objects that are very near, we don’t have rigid views about what should or should not be in focus. Therefore, if we were to see a close up photograph of a flower that was all in focus, we wouldn’t think it looked artificial.

But the fact remains that the nearer we get to an object, the smaller the depth of field.

So what is a photographer to do if he or she wants to photograph something that is very near the camera – and wants to get everything in focus?

Small Apertures
One way is to set the aperture of the lens to the minimum possible. The aperture simply describes the hole in the lens through which light enters the camera. The size of the hole can be made bigger or smaller to suit the photograph that is being taken. Most modern lenses can be closed down to a very small hole.

But even at the smallest aperture the depth of field for objects that are very near the lens can be just a fraction of an inch. That isn’t enough to make everything from front to back of an object that is near to the lens appear sharp.

Also, for subjects that are very close to the lens, small apertures degrade the image because of the effect of diffraction. Diffraction causes the light around the edge of the hole in the lens to scatter and spill light all over the image, blurring it.

As a side note, we might wonder why lenses that can shut down to small apertures are made if they suffer from this diffraction problem? Well, for objects further from the camera the effect of diffraction is not so noticeable. Also, small apertures are useful for cutting down the amount of light that enters the camera – for example when a photographer is shooting a scene in bright daylight.

However, if depth of field is small and diffraction is a problem with objects close to the lens, we need another approach.

Focus Stacking
One way is to take several shots working from back to front, each time focusing on a different part of the object. Then combine each photograph to make one photograph with everything in focus.

It’s not as easy as it sounds because each time the camera is re-focused, the size of the object changes slightly. So what is needed is an automatic way of stacking the individual frames to produce one sharp image.

That’s where focus stacking software comes in. Feed several images in and the program creates a composite based on the sharpest plane of focus of each of the images.

These two images of a yellow gerbera flower were both taken with a medium aperture. The first is just one photograph. The second photograph is a composite of several photographs, each focusing a slightly different distance into the image.

Focus Stacking Software
I’ve just started to use a program called ZereneStacker to produce this kind of photograph. I need to refine my technique because the program is unforgiving of small errors. But I am hooked on the idea because making close-up photographs is something I have been interested in for a long time, but until recently I didn’t know this kind of program existed. There are a couple of other similar programs I want to look into, and I’ll post the results here. If they work out well, we will add the photographs to the Quillcards ecard collection.

You can send distinctive ecards featuring our photographs by Joining Quillcards.

What you are looking at is a swallow hanging onto to the side of its nest. The nest is made of pellets of mud which the swallows make like a potter building a pot.

You can see the darker layer of mud at the top that has not yet dried. It reminds me of a young couple in a hurry to get on with things, moving into a house where the paint has not yet dried.

The perspective may appear a little odd. The white part is the ceiling of the barn; the darker part is a beam, and the nest is glued into the right angle between them. This photo is a crop from the whole frame, and the barn was dark, which is why the image is noisy and blotchy.

There were people coming and going around the entrance to the barn and the swallows deftly wove their way around them while I took some photos.

I watched the swallows diving and twisting outside, snapping insects. Then they came in, left the food they had caught with the brood inside the nest and off they went again, quicker than it takes to write this sentence.

Then one of them disappeared inside the nest for a while, with just its head and a tiny beak peeping out.

Taking a photograph is always a compromise between the available equipment and the quality of the light.

In the middle of the day with the sun overhead, there is plenty of light but things do not usually look at their best. Waiting for the right light isn’t an option if the subject will not hang around, so the compromise is between getting the shot in the midday sun, or getting no shot at all.

Sometimes you can shade the subject from the overhead sun, but it depends upon how big the shade is, or how small the subject is. In this case my body was enough to shade this subject and take out some of the harsh noonday shadows – about which more below.

Diffusers and Reflectors
In sunny conditions photographers will sometimes use sheets of translucent material that are big enough to cast shade over a model and even out the shadows and highlights. The material is stretched over a frame so it can be manhandled and moved into position to block out the specular light from the sun. And photographers will use equally big reflectors to bounce light back into the shadows. Google for the ‘California Sunbounce’ to see some very big diffusers and reflectors and shots of how they are used.

Specular Light
Specular light is light that comes from a small point source. The sun is big, but being so far away it gives a specular light with harsh transitions between light and shade. And it drains the colors from everything it hits. Flattering light is the kind you would get on a bright, clear day with the sun hidden behind a convenient hill, with its light bouncing off a bank of cloud and scattering its rays into a diffused glow.

Shoot Indoors
Shoot indoors by a window that is not in direct sunlight, and your subject will be bathed in directional light. This helps sculpt the subject to give a more three-dimensional look. The nearer the subject is to the window, the faster the fall-off of light and the harsher the transitions from highlights to shadows. Move the subject deeper into the room, and the highlights will taper off more gently into the shadow areas.

Portable Flash
Many professionals use portable flash to take out the harshness of noonday shadows, but that creates its own look, and perhaps you want a more natural look. And flash equipment that can bathe the subject in a gentle light is neither lightweight nor small. The light from a flashgun mounted on a camera is still going to be specular – though to be fair, you can sometimes give the subject a little ‘pip’ of flash to lift the shadows. You can do this by setting the controls on the flashgun to give just a touch of additional light to the subject, rather than having the flash overpower the ambient light.

But getting reliable and consistently repeatable results from flash in any conditions means having a soft, even light. That requires something big to bounce the light from the flash through. This might be a softbox – a sheet of translucent material stretched over a frame, or a translucent umbrella to shoot through. That in turn means a bigger flash – a strobe rather than a little flashgun.

Deciding how much equipment to take and what to leave behind on account of its size and weight is another compromise the photographers must make.

The Light At The End Of The Day
If the mid-day sun in unflattering and your subject will hang around to the end of the day, you can wait. Then you can take advantage of the gentle shadows that strike obliquely and make subjects look more sculpted and three-dimensional. But at the end of the day the light levels will be lower and that brings its own problems.

A Detour Into Film Speed And Grain
If you are shooting film, you have to decide which film to use. Every film (both black and white, and color) has its own ‘look’ but every film is also rated for speed, or to put it another way, for sensitivity. Film manufacturers understand what photographers want and they formulate and produce films in a range from less sensitive to more sensitive to suit different light levels.

And of course there is a trade-off: Slower speed films deliver the smoothest results. Faster, more sensitive film show more grain.

Grain is undesirable because it makes the subject look blotchy, but in the heyday of film, newspaper photographers took that problem in their stride and developed a style built around the grain of certain films. Kodak Tri-X is a black and white film that was and is a favorite with news photographers.

The Advantages of Speed
Faster films aren’t just for shooting in darker conditions. Kodak Tri-X is rated at 400 ISO, which means it is four times more sensitive than a standard film that most consumers would buy for shooting outdoors. That means in turn that a photographer can use a shutter speed that is four times faster than he would have to use with a slow film, which enables him to capture a moment rather than a blur.

Sabastiao Salgado
Sabastiao Salgado is a world-famous photographer who uses Tri-X to document the dignity of man in the most terrible circumstances. He has learned how to make dramatic and remarkable photographs using this fast and grainy film. Google for his name if you are not familiar with his work. It is well worth it.

Changing Rolls
Photographers who shoot film will carry rolls of different film in their camera bags. They will have fast film for action and indoor shooting, and slow film for bright daylight. If you shoot a whole roll of film outdoors then a slow film will be suited to this. But what if you shoot half a roll and then move indoors?

Professional photographers were forever swapping part-exposed rolls to put a more suitable one in their camera. Then they would feed the part-exposed roll back into the camera later. And they would have to remember how many exposures they had taken before they took the roll out. It was a constant source of tension and worry.

Digital Cameras
Now with digital photography we can increase the sensitivity of the sensor just by turning a dial on the camera.

However, as we increase the speed of the sensor, the camera amplifies the signal from the sensor beyond its optimum value. And the trade-off for this extra sensitivity is that along with the increased signal comes increased noise. Noise is the name given to the digital equivalent of grain in film.

Digital Noise
However, digital noise is less attractive than the grain from which fast films suffer. It shows in the photograph as black and colored speckles as well as ‘artefacts’. Artefacts are tiny odd shapes that aren’t there at all in the subject that is being photographed. They are what the camera sensor itself makes when it does its best to fill in the gaps in the signal.

Cameras are getting better though, and in the past ten years the progress has been dramatic, with cameras that can shoot in low light with very little noise. Now photographers can shoot in range of conditions that were once unthinkable.

But despite that, the quality of light is still something that photographers have to take as it is – for better or worse. If it is midday they still have to contend with the harsh overhead light from the sun.

Coffee On The Terrace
A week or two ago, Tamara and I were sitting having coffee on a terrace. It was late afternoon and the sky was dark. But through a break in the clouds the sun shone through at a raking angle and that is when I took this shot.

I like taking photos of waiters – there’s something about the uniform that makes the scene gel. When I saw the exposure in the LCD in the back of the camera, I could see how the low, raking light had sculpted the elements in the scene.