Landscape photography requires a sound photo-technique, even when using the most sophisticated digital camera. In addition to new techniques, these pages offer traditional photographic advice, techniques that I learnt 50 years ago and just as important today.
Some advice will be better implemented in conjunction with the camera's instruction book.
1. PROGRAM OR AUTO 2. SHUTTER-SPEEDS 3. APERTURES
4. ISO SENSITIVITY 5. PROGRAM & RESET 6. THE PHOTOGRAPHIC EYE
7. METERING MODES 8. RAW OR JPEG 9. SPOT-METERING
10. HDR (High Dynamic Range) 11. LENSES 12. DEPTH-OF-FIELD, THE BASICS
13. DEPTH-OF-FIELD, IN PRACTISE
Know your camera
Click on a topic
AE Lock stands for Automatic Exposure Lock, usually a button on the camera body of advanced cameras such as Digital Single Lens Reflex (DSLR) models.
When the shutter-button is half-depressed the camera takes an exposure reading (and focusses on the subject). At this stage the photograph has not been taken, but pressing the AEL button will lock the exposure reading. Its use is for more specialised applications (for example spot-metering, where the exposure needs to be locked).
The way the AEL button functions can be varied by accessing its control in the camera menu. Usually when the button is released the lock is removed, but depending on the camera model, it is also possible to maintain the lock until the photograph is taken.
The use of the AEL button is discussed further in spot-metering.
All Reset (or a similarly worded option) will be found within the menu of many cameras. Activating the All Reset control returns the camera to its factory default setting, cancelling most (if not all) personalised settings. It is very useful when the photographer purchases a new camera as it enables the user to explore thoroughly the camera's controls safely in the knowledge that should the experiment turn pear-shaped, there is an easy route of escape.
However, some cameras leave the factory with the All Reset turned on as a default setting. Turn it off, otherwise it can be annoying as any intentional changes the photographer wishes to make to the camera's settings (like turning the flash off) will be cancelled returning the camera to its default setting every time it is switched off.
Some older and inexpensive cameras do not always have this facility and will return to the factory default setting whenever they are turned off.
Aperture Priority (Aperture Value on some cameras) like shutter-priority, allows the photographer to take control, but the objective is different.
A shutter-speed and an aperture give a correct exposure, but apertures also control depth-of-field. This is explained elsewhere, but a small aperture (f22) creates an extended depth-of-field, whereas a large aperture (f2.8) creates a shallow depth-of-field. The values in between extend or decease the available depth-of-field, but the exact amount depends on several other factors including focal length of lens and physical size of sensor.
Aperture Priority is useful for shooting into the light, particularly if the sun is in the composition. This scenario should come with a health warning regarding your eyesight, it can also cause degradation to the image known as flare.
Flare is avoided by closing down the lens to its smallest aperture - f22 on DSLR cameras, f8 on most compacts and bridge. There should be sufficient light to handhold, but using the smallest area of the lens reduces flare.
An aperture is a value expressed as a factor (f) number and indicates how much of the physical size of the lens is being used to control the amount of light reaching the sensor. The size of the aperture is shown as a seemingly unhelpful set of numbers; the basic ones are:-
f2.8: f4: f5.6: f8: f11: f16: & f22
There is a technical relationship between these numbers and a lens, but that need not concern the novice. However, f2.8 is the largest aperture allowing more light to reach the digital sensor, whereas f22 is the smallest and as you proceed across the scale the amount of light reaching the sensor is halved at each stage.
This has been at the bedrock of photography for years and it still applies today even with the most sophisticated computerised camera. The correct combination of a shutter-speed and aperture will always produce a perfectly exposed image, but computerised cameras also show the factor values of apertures in between such as f6.3. This is useful for the sake of accuracy, but confusing when trying to understand the principle!
A lens with f2.8 as its largest aperture is capable of allowing more light to reach the sensor than an f4 lens and therefore better at taking shots in low light without flash. But don't forget that a shutter-speed which determines how long the aperture remains open also contributes to the equation that controls the amount of light reaching the sensor for a correctly exposed image.
Note: The smallest aperture available on compact and bridge cameras is usually f8.
Digital cameras are 100% dependent on good batteries and unlike some film cameras there are no mechanical models.
Getting a set of batteries to last the day's shoot can be a problem but it need not be. More can be done before the shoot than carrying a spare set, particularly if they have not been properly charged.
Basically there are two types - disposable and rechargeable. Whichever the photographer chooses avoid cheap alternatives - they may not last the day! The more expensive are usually more reliable, particularly those bearing a recognisable name renowned for specialising in batteries, or those with the name of the camera manufacturer. Although it is unlikely they are made by them, a camera manufacturer is not going to add their name to a battery in which they have no faith.
Rechargeable batteries are normally more expensive, but worth the additional outlay. Recent developments now allow recharging at any time, it is no longer necessary to wait until they have run down. On a shoot lasting several days it is considered good practise to recharge the batteries every evening.
Depending on quality and reliability, rechargeable batteries will not last for ever. If they start to prove unreliable - replace!
Note: The quickest way to exhaust any battery is to leave an image displayed on the camera's screen! Also, turning a camera off and on repeatedly does not help, best to allow a camera to go into sleep mode whilst on a shoot.
When the whole picture is unsharp the most likely cause is camera shake. This usually happens when a picture is taken in low or poor light, forcing the camera to use a longer shutter-speed than normal for a correct exposure, therefore making hand holding the camera difficult.
At what point a shutter-speed causes camera shake depends on several factors. They include how the camera is held and the type of lens used, but a shutter-speed longer than 1/100 second is at risk of being in the 'camera shake' zone.
Posture is important, not helped now by having to use a screen instead of a viewfinder. Not having the side of the face for support increases the risk of camera shake. The possibility of camera shake also increases whilst using the telephoto end of a zoom lens. Holding a camera aloft with one hand for every shot is not only bad practise, but strictly for 'posers' as it is a blatant display of photographic ignorance!
Many photographers use a tripod to ensure a sharp image. However, with the introduction of image stabilisers in camera bodies and lenses, camera shake at long shutter-speeds has become less of a problem.
Deleting & Formatting
When a memory card is formatted in camera all files including photographs are marked for deletion and cannot be retrieved. Formatting also checks the suitability of a card for the camera. When taking a memory card out of one camera and put in another, check first there are no images on it and then format before further use, otherwise it may not function correctly.
Images can also be deleted individually, but they remain on the card! Space is made available for another picture, overwriting the image marked for deletion. If an image is deleted accidentally, the card should be removed immediately from the camera so that it can be recovered in a computer using special software.
It is not recommended that photographs are deleted whilst the memory card is in a computer as extraneous data can be transferred. However, formatting a card regularly in camera is good housekeeping, this ensures that the card is being used to its full capacity.
Do not use a memory card to store precious images permantly. If they fail, they do so without warning and it is a rather expensive way. If you have a computer consider storing images on CD or DVD in duplicate, or on an external high capacity hard drive.
Depth-of-field is the most misunderstood, most ignored technique that can turn a snap into a photograph. Exposure can be left to the camera, but to take charge of depth-of-field requires a traditional photographic technique irrespective of camera.
When the photographer focuses on a subject, part of the image in front of and behind the subject will also be in focus. But working out how much is not easy. It is dependent on aperture, focal length of lens, distance between photographer and subject and the physical size of sensor. Regardless of how these parameters are set the ratio is always the same - 1/3rd in front of the subject 2/3rds behind. Therefore if depth-of-field, as governed by the conditions above, turns out to be 6 inches in front of the subject, it will be 12 inches behind.
Using a small aperture (f22) will increase depth-of-field and additionally so does a wide-angle lens, but a large aperture (f2.8) and a telephoto optic does the opposite. Depth-of-field is also reduced the closer the photographer gets to the subject, especially less than 3 feet. Furthermore, the small sensors found in compact and bridge cameras seem to extend depth-of-field even further across the board, irrespective of other settings.
Because camera manufacturers cannot agree on the physical size, even shape, of the digital sensor, it is impossible to present a meaningful table; but an understanding of the basic concept of depth-of-field will assist many other aspects of photography, especially composition.
A digital zoom is not a true zoom - it does not produce the same result as an optical zoom lens.
An optical zoom lens changes the perspective. By moving the elements of a lens it brings the subject closer to or further away from the photographer without any significant loss of image quality.
A digital zoom achieves a similar effect digitally by cropping the image in camera. However, it does not change the perspective, therefore the increased telephoto effect is an illusion. Also by cropping the image it reduces the number of pixels which at the extreme 'telephoto' will cause pixelation as well as increasing the risk of camera shake.
Most of what a digital zoom does can be achieved with a computer using an Image Maniplation programme like Photoshop or Paintshop Pro. The advantage is that provided the photographer makes a copy first, any adjustment to the image can be undone, something that cannot be achieved with a digital zoom in camera.
Treat with caution!
Digital sensors if left exposed to the atmosphere are prone to attracting minute particles of dust resulting in imperfections that blot out parts of the image. Whilst they can be recovered in a computer, it is a time-wasting exercise.
For bridge and compact cameras with a permanent lens, because they are sealed, then dust reaching a sensor is not a problem. The moment a camera has a facility to remove a lens from its body such as a DSLR, then more care in camera design becomes crucial and one that should not be fudged.
A quality sensor with even a dedicated digital lens are not the only important features for a well-designed digital camera; if the sensor is not properly protected from dust, then these qualities are wasted.
The problem, or risk, occurs when changing a lens, exposing the delicate sensor to the elements. Holding the camera so that the lens faces the ground is not a satisfactory answer, especially on a wind-swept beach!
Protecting the sensor should be one of the first considerations in camera design, more easily achieved if it is designed from a blank sheet of paper. Personal research by the photographer will soon reveal which of the manufactures have tackled this problem diligently.
Exposure Compensation changes the EV (Exposure Value) and is available in Program, Aperture & Shutter Priority and Manual. It is not available in Auto or the Scene Modes.
Exposure Compensation adjusts the reading by increments regardless of other settings. They are taken into account, but by adjusting Exposure Compensation it is possible to over or underexpose the final result by 1/3rd or 1/2 stop increments.
Some subjects, particularly those illuminated by light of high contrast, can sometimes fool the most sophisticated of exposure metering systems. Exposure Compensation can help to correct these problems, but is only successful by trial and error and by evaluating each shot where that is possible.
Where time is important, particularly when the shot cannot be repeated, try underexposing by up to 2/3rds stop and saving the image preferably as a RAW file. Underexposure will avoid blown-out highlights, difficult to recover in a computer, but where parts of the image are underexposed, they can be corrected in a RAW converter before being saved as a TIFF or JPEG file.
Underexposure by Exposure Compensation if used judiciously can also enrich colours without making them appear artificial.
Most digital cameras have built-in flash - sadly, many people don't know how to turn them off, a fact most noticeable at large public events!
A built-in flash particularly in a compact camera is intended for indoor social photography, not for illuminating vast spaces. It is a conceit to think that the humble compact is capable of such a Herculean task, so they are best turned off.
The factory default is Auto, so the flash will fire whenever the light intensity drops below a certain level. Usually there are three further settings - Red-eye, On or Off, the last being particularly useful!
Red-eye setting is also useful, but the photographer will notice a slight delay before the picture is taken. This is because the flashgun operates a pre-flash for red-eye which adjusts the sitter's eyes before the main flash fires.
Outdoors even on a dull day the flash should be turned off. It will have little or no effect, unless you are knowledgeable about fill-in flash. That would require a more advanced camera that can control the amount of flash delivered to the subject, a technique much loved by wedding photographers.
Flash is very selective. When photographing a family group in the centre of a room, the background will be underexposed. Furthermore beware of reflective surfaces, especially glass and even polished wood, they will burn-out.
The lens focuses on the subject as soon as the shutter button is depressed. Most of the time it works, but occasionally it will focus on the wrong part of the image, particularly if the subject is off-centre.
Auto-focus is wonderful, but photographers tend to rely on it too much without considering the alternative. Some cameras even have as many as ten or eleven focusing points - surely nothing can go wrong now? Well when it does, there is always face recognition, but I want to photograph a dickybird!
Automation can encourage laziness. We tend to overlook what some of us learnt many years ago that is still useful today. Digital Single Lens Reflex Cameras do have a facility to focus manually and if the photographer has a few seconds to spare, it is much the preferred way and usually more accurate.
Auto-focus has valuable uses, especially action, but with focussing and many other aspects of photo-technique, don't forget the alternative, particularly if it is the traditional way.
Image order in Windows
Whenever a picture is taken with a digital camera, automatically it gives a sequential reference number; for example P1234 followed by P1235. However the numbering varies from camera to camera, with some allowing the photographer to adjust the default prior to photography.
After the photographs have been downloaded to a computer, Windows Explorer uses the reference numbers created by the camera (known as Metadata) as a default for viewing. However a totally numeric number takes precedence in a listing over a number beginning with a letter, even if it is followed by a number. When downloading from several cameras to the same folder the images are still displayed in Windows default order, but now dictated by the numbering system that each camera uses for the images, therefore not necessarily in the order of taking.
The Windows default can be changed in Vista and Seven. In Explorer change the View option to Detail. The detailed information is now shown under separate headings and by executing a single left click on a heading; for example Date, the order of the images changes and are now shown in descending date order irrespective of the numbering system; for ascending click Date again. Further options include file size and file name (or number) and when returning to other views, the new order is maintained, but the Windows default may return when the computer is switched on again.
However, as the date and time data is derived from the camera, it will only work if it has been set correctly before a photograph is taken. It is also important to observe changes from GMT to BST and when travelling abroad to have the correct time zone. When using more than one camera, ensure that they are synchronised with the same date and time.
These guidelines apply to Windows Explorer only. If the same photographs are subsequently viewed in a different Organiser, the order may change if the default is different to Windows. It may still be possible to change it and some, for example the Organiser in Adobe Photoshop Elements, provide more options for photographs downloaded with the programme. Some Organisers because of their superior sophistication can show images in an order that Windows Explorer cannot do. For guidance consult the relevant instructions or Help file for the software programme, or check advertising literature prior to purchase.
Image Stabilisers are now a common feature in digital cameras; some are in lenses, others in the camera body, but their use is the same, counteracting the physical movements of the photographer that could cause camera shake when hand holding in low light.
The way they function varies from make to make with some offering the option of a correction when photographing from moving transport, such as a boat or a vehicle.
Under normal use it is a good idea to leave the image stabiliser on, but remember to turn it off when mounting the camera on a tripod or other firm support; otherwise it still tries to compensate for handshake, which is not present, resulting in an unsharp image!
The sensitivity of a digital sensor works in a similar way to film ISO. With a film camera when it became necessary to shoot in low light without flash, the photographer purchased a film with a high ISO factor - usually 400 or 800. The problem was that everything regardless of light intensity had to be taken with the high speed film.
With a digital camera the ISO sensitivity can be adjusted just for the shots that require a higher value. Usually a sensor is working at its optimum best at 100 or 200 ISO, but a low light shot such as a church interior, would require a higher value of at least 400 for hand holding without camera shake.
The ISO values usually commence at 50 or 100 with each increment doubling in value - 200, 400, 800, 1600 and so on. At each stage the sensitivity of the CCD is doubled, so if at 100 (and with a constant aperture value) the shutter-speed is 1/8 second, at 800 it will be 1/60 second. In many cameras, particularly compacts, the ISO can be set to Auto, which should adjust automatically for differences in light intensity.
There is a possibility of a visual imperfection to the image called Noise when using higher ISO values. Recent improvements in digital technology has lessened this problem, but increasing the ISO value of the sensor should only be implemented when necessary.
Note: ISO Sensitivity should not be confused with EV Compensation.
There are at least three different file formats that a digital camera can use to save a photograph to a memory card, but the most popular and usually the factory default is JPEG, an acronym for Joint Photographic Expert Group!
The main feature of a JPEG image and an advantage for many amateur photographers is its ability to compress an image to save space on the memory card allowing more images to be saved. However, the amount of compression, which is a highly sophisticated and complicated process, can be varied, affecting the capacity of the memory card.
Different cameras even within the same stable present this information in a variety of ways. There is no standard, so for more precise information the photographer has to consult the instruction book, which is often presented as a table that include the other file formats TIFF and RAW.
Broadly speaking, the more an image is compressed to increase the capacity of the memory card, the more noticeable will be a reduction in its quality. A heavily compressed image is useful for emailing and prints up to postcard size, but anything larger demands a better quality image with less compression to preserve its sharpness and colour. At this higher quality setting the capacity of the memory card is reduced. Photographers with computer skills usually save their images at this best quality setting and then exercise the option to make a copy, downsizing it in Photoshop for emailing.
It should be noted that a high quality photograph saved as a JPEG file with the least compression is not suitable for emailing, whereas a JPEG image heavily compressed for emailing is unlikely to produce a quality enlargement. Photographers who do not possess computer skills need to make some important decisions first and set the required compression for its use before a picture is taken.
Before zoom lenses photographers used prime lenses. The angle of view for a prime lens was fixed, sometimes known as a fixed focal length lens. A new film camera would have been supplied with a standard lens with an angle of view similar to our eye sight. On more advanced cameras the photographer would have the facility to remove the standard lens, replacing it with either a telephoto lens (again of fixed focal length), or a wide-angle.
With the introduction of zoom lenses the restrictions imposed by a prime lens were removed. It became possible to change the field of view continuously between two limits dictated by its magnification and expressed as a number - e.g. 3x or 5x. Most common was a lens that started its zoom ratio as a modest wide-angle with a low focal length number, passing through standard to a modest telephoto with a much higher focal length number. This made composition more convenient, such as removing that wastepaper bin on the edge of the picture.
These optical zoom lenses (not to be confused with digital zoom) have different rates of magnification, some covering the telephoto end of the spectrum, others wide-angle. Unfortunately unlike film lenses, digital does not have a standard to allow an easy comparison, but generally a focal length with a high number will give a pronounced telephoto effect, whereas a focal length with a low number is wide-angle.
Macro is close-up, as a rule when the photographer is closer to the subject than 3 feet. Compact and bridge cameras have a built-in facility to adjust the way the lens focuses for macro and usually access is via a button having a tulip symbol. For a digital single lens reflex camera it is normal to change the lens to an optic dedicated to the purpose.
When taking a macro shot using a compact camera that has both viewfinder and screen, it is best to use the latter. Because the viewfinder is an entirely separate optic to the lens, the physical displacement between the two becomes a problem the closer the photographer gets to the subject and is known as parallax. It is not a problem for bridge or DSLR cameras as the photographer is composing the picture through the lens.
Depth-of-field is reduced dramatically when using macro, therefore understanding how aperture and lens choice affects it becomes more important. Whilst it is best to employ either the standard or wide-angle end of a zoom lens to create a workable depth-of-field, the fine tuning comes with choice of aperture. This depends on individual circumstances, but if the aperture is too large the whole of the subject may not be in focus. An aperture too small could bring the background into focus, merging it with the subject.
Developments in 'Live-View' which give a digital impression of the photograph may prove useful in the future to see if depth-of-field is enough, or too much.
In the days of film the dedicated amateur often took a notebook to record photographic information about the shots, such as shutter-speed and aperture. Some photographers still take a notebook without realising that whenever a digital camera takes a picture, this information and much else is automatically recorded by the camera and is known as metadata or EXIF information.
If a digital photographer does not have a computer, then perhaps a notebook is still essential, but for those who have a computer this information can be accessed after the images have been downloaded.
Most digital cameras come with their own software, the use of which is optional, but when used EXIF information should be comprehensive, but accessing it will vary between manufacturers. Alternatively it can be viewed without special camera software by using Windows XP, Vista or 7 by right-clicking on the image for the submenu and choosing properties.
In addition to showing a comprehensive list of camera information, all of which is automatically recorded, it will also show the date and time for every photograph. This must be set manually first via the camera menu, otherwise this part of the information will be incorrect! Most cameras do not adjust automatically between time zones and daylight saving changes, such as Greenwich Mean Time and British Summer Time in the UK.
Most digital cameras provide a facility to change the way its metering system evaluates a scene. Some also have a feature that take several images simultaneously at different settings. This is known as bracketing and a common use would be three shots at half stop variations above and below a correct exposure; useful for a difficult scene of high contrast or action that cannot be repeated.
A digital camera will offer at least three different choices for metering a scene - the most common being matrix, centre-weighted and spot. Matrix is where the view is divided into 49 segments (7 x 7), and each segment evaluated, but the photographer wishing to take a little artistic control will select one of the remaining two options.
Spot (not to be confused with the technique of spot-metering) concentrates the evaluation on a central section of the camera screen, sometimes indicated by a circle or rectangle. It is a little unforgiving if the photographer does not accurately pinpoint the area for precise metering; best used for difficult light of extreme high contrast.
In between spot and matrix is centre-weighted and it does what it says, concentrates the reading on the central area, but taking into consideration the outer portions of a scene. The percentage between the two will vary between cameras of different makes.
Centre-weighted metering is best for the technique of spot-metering, see separate entry for more information
Noise like film grain, is an imperfection in the digital image, usually manifesting itself as speckles of foreign colour. The most common cause is a high ISO setting, but some cameras have a noise reduction facility within the menu. Noise can also be removed with mixed success in an Image Manipulation program.
Recent technology has resulted in an improved performance when pushing a digital sensor up to a high ISO setting, but this may only be found in more expensive cameras. To avoid noise in any situation, only increase the ISO value from 100 or 200 when absolutely necessary.
Pixel means Picture Element, a microscopic part of a sensor capable of recording a single colour from millions of hues. A group of pixels with different hues will start to create an image.
A major selling point for a digital camera is the number of pixels it has for taking a photographic image. Many have at least 10 million, but a camera with a greater number will not necessarily guarantee a better image as pixel count is not the only criteria for determining its quality.
A true digital camera will have a lens designed for digital photography. Some digital lenses are twice the resolution of their equivalent film lens and of tele-concentric design delivering light to the digital sensor at right angles over its entire area. It is false economy to use a film lens on a digital camera no matter how well it performed on a film camera, as it delivers light to the sensor at an incorrect angle causing aberrations and vignetting at wide aperture, wasting the potential that a higher pixel count might give.
Note: Jargon is a confusing animal and with a camera boasting 10 mega-pixels, the word mega, according to the Oxford English Dictionary, can also mean large and it comes first in its listing of meanings. What is meant is obvious, but a humorous thought is inescapable, a digital photographer with a new camera with 10 rather large pixels!
Program or Auto
Many digital cameras provide the facility to take pictures in Program or Auto, a choice normally available from the mode dial, and whilst both deliver an accurately exposed image, there are important differences.
Auto is the factory default setting where the camera will use preset controls such as White Balance and ISO Sensitivity which cannot always be altered. At this setting a glance at the camera menu will reveal that some choices are now blanked out leaving the photographer without the facility to tweak the controls for further creativity.
Program makes these choices available. They are options, but using Program is essential if the photographer wishes to follow the advice offered elsewhere in this Tuition, particularly Exposure Compensation and ISO Sensitivity.
More recent advanced cameras have a facility called Program + Shift. Whilst exposure in this mode remains automatic the photographer is able, via a control, to set the aperture or shutter-speed whilst in Program without the need to switch to Aperture or Shutter Priority.
When taking photographs to be saved as a JPEG or TIFF file, before transfer to a memory card, the digital information is 'processed' by the camera's computer, which takes just a few seconds. After downloading to a computer the processed file can be adjusted in a software programme such as Adobe Photoshop Elements. However, there is a strongly held view that any alteration to a digitally processed image, even in a renowned software programme like the full version of Photoshop, runs the risk of a reduction in image quality, particularly if it is a compressed JPEG.
RAW, which is not an acronym and means what it says, is the preferred picture file for professional use. When saved as a RAW file the photograph bypasses the camera's computer processing, saving it to a memory card unprocessed. After downloading and when opened, the processing takes place in the memory of the computer to produce a full colour image on the screen.
The advantage is that adjustments to exposure, contrast, white balance and many other things can now be carried out in the memory of the computer without damaging the file before being saved as a processed JPEG or TIFF file. The original RAW file remains unaltered and becomes an archival copy. It is like having a film camera where you can make corrections to the photograph before it is processed.
The downside is that the saved file is uncompressed and takes up more space on a memory card and each RAW file requres a 'patch' for every make of camera which the software vendor has to provide before it can be opened on a computer.
Scene Modes are preset controls for certain photographic subjects that would otherwise require a specialist knowledge. Some are useful, others rather exotic and some tell the photographer what the camera is doing. Very useful are sports for freezing movement and landscape plus portrait for creating an extended depth-of-field.
Use of the preset controls will cancel any personalised settings, such as EV Compensation and ISO Sensitivity. These, together with others, are set by the camera as required and usually cannot be adjusted.
Scene Modes do not teach photography. They are quick and convenient to use and designed to widen the photographic possibilities for non-photographers, as a stepping-stone towards 'real' photography; or where manual control of a camera is not possible, particularly some compact cameras locked into Auto.
Shooting in Program or Auto will, in most cases, produce a well-exposed image, but photography is much more than just pressing a few buttons or being a slave to a camera!
There are many occasions when the photographer needs to take charge and photographing movement is one where controlling the shutter-speed is necessary.
Shutter Priority (Time Value on some cameras) permits the photographer to choose the shutter-speed suitable for an application. When the shutter button is now depressed the camera selects the appropriate aperture for correct exposure. However, if the required aperture is outside the camera's range because the chosen shutter-speed is either too short or too long with a consequential risk of under or over exposure, it will give a warning signal.
A shutter-speed of extremely short duration freezes action, but a long shutter-speed will blur movement. A short shutter-speed is also useful for preventing camera shake with a handheld telephoto lens.
Spot-metering is for the photographer who wishes to take more control of exposure. Metering systems offer several choices, but for the photographer wishing to take a risk, spot-metering adds that special sartistic flair that even the most sophisticated computerised control cannot equal.
It is for photographers who use their eyes, but it comes at a price - experience. It is not 'instant gratification', but closer to 'practise makes perfect'.
The photographer starts the process by evaluating the scene with their eyes, searching for that illusive part of the image to spot-meter from that shows the best colour density and luminosity for the entire view; usually looking for a tone midway between the darkest shadow and brightest highlight.
The technique of spot-metering, not to be confused with the spot metering mode, works best with the exposure meter set to centre-weighted. By half-depressing the shutter button the photographer takes a spot-meter reading, as described above. If the metering point is not the required composition, maintain light pressure on the shutter-button to lock the exposure, recompose and take the shot. Alternatively, pressing the AE Lock will also retain the spot-metered reading until the shot is taken.
Note: If auto-focus is on, detach if possible and focus manually when spot-metering is not the focus point.
Viewfinder or Screen?
The advent of the digital camera brought with it many changes in camera design, not all of them improvements and many driven by market forces who are not photographers!
The appearance of a screen on the camera's back plate to view images may appear to be a significant improvement, but when it comes to taking pictures, it has many disadvantages.
Photographers who wear spectacles or whose vision is impaired will find using a screen easier than a viewfinder, that is until you are photographing in bright sunlight! There are other advantages in using a screen in preference to a viewfinder, most noticeably macro (close-up) when what you see in a viewfinder is certainly not what you get!
At first a screen was offered as an alternative to the viewfinder, but now it is very difficult to purchase a compact camera with both. As discussed elsewhere, holding a camera at arms length to take a picture, even with both hands, increases the risk of camera shake and following a moving subject is much more difficult.
Bridge cameras and Digital Single Lens Reflex Cameras usually have both giving the photographer a choice, but to see which is best, observe how a professional photographer takes a picture, their skill and expertise nurtured over many years presenting a technique that demands the use of a viewfinder almost every time.
Digital Cameras allow the photographer the invaluable opportunity to immediately check the quality and composition of a photograph on screen.
Whilst a computer is more reliable for an overall assessment, sharpness can be checked by magnifying the image in camera; this does not alter the picture. Exposure details about the image are also accessible for checking resolution, shutter-speed, aperture and ISO sensitivity - on some cameras accessed by depressing the display button repeatedly to cycle around several options. The photographer can also check for areas where there is no detail or tone in highlights or shadows.
Many cameras, even compacts, have a histogram, a graph for checking exposure balance. If the graph is weighted to the left - the image could be underexposed, to the right - overexposed. Generally a well exposed photograph will show an even balance across the graph with perhaps a slightly higher reading in its centre. However, a great photograph can easily have a histogram that looks wrong.
More recent DSLR cameras now offer 'Live View'. This presents a more accurate impression on screen of how the image will look digitally instead of optically. Exposure information is shown allowing the photographer to make important adjustments before the image is taken.
If in doubt, do not delete! Wait until the photograph is downloaded to a computer before making a decision that you may not be able to undo in camera.
Colour reproduction depends on the quality and type of light. An obvious example is the difference between daylight and indoor light, the latter provided by a tungsten bulb imparting a warm ambience to the surrounding scene. There is also a subtle difference between daylight illuminated by direct sunlight and that filtered through a heavy cloud. Normally our eyes adjust automatically to these differences in white balance and is known as colour temperature.
Within the menu of a digital camera is a facility to change the white balance manually, often with settings for sunny, cloudy and tungsten, amongst others. In all probability a camera will be set on Auto, the factory default and for many applications it will sort out any differences in white balance.
Occasionally it needs a bit of help and most noticeable when the image ends up with a colour cast. Left on Auto there are times, for example, when a shot taken on a cloudy day appears cold with a blue cast. This can be corrected by changing the white balance to cloudy which will warm up the cold tones. The photographer may experience other scenarios where white balance needs to be adjusted manually.
Note: It may not be possible to change the white balance if the camera mode dial is on Auto (not to be confused with the white balance auto setting). Change to Program, Manual, Shutter or Aperture Priority to access the menu.