Wednesday, May 4, 2016

How to Control Aperture and Shutter Speed on an Entry Level Point and Shoot Digital Camera



Darren, thanks for your recent articles on aperture andshutter speed, they were really interesting. My problem is that I have a point and shoot camera that doesn’t have the ability to change aperture and shutter speed manually. I would especially like to have more control of aperture and depth of field – is there any way I can do this without upgrading my camera? Submitted by Susan.
Good question Susan – it’s one I’ve had a few times of late so you’re not alone as a Point and Shoot user wanting more control over your settings.
Really you have two main options.

1. Upgrade your camera

The first of these options is probably ideal if you want real control over the settings your camera uses for aperture and shutter speed. While you can do a few things to ‘trick’ your camera (see below) you’ll be limited in the exactness in the settings it will choose.
If you’re looking to upgrade you’ve got two main choices – a DSLR or another point and shoot with more manual control (read this tutorial on making the choice between DSLR and Point and Shoot cameras).
Probably the best bet if you’re after complete control (in more than just aperture and shutter speed) is to go for a DSLR which will let you add a variety of lenses, shoot in full manual mode (in most cases) and have lots of control over other elements such as ISOwhite balance, exposure etc.
Alternatively look at a more advanced point and shoot. These days even some of the more basic point and shoot cameras coming onto the market come with manual or semi-manual control. If you go for a point and shoot look for something that at least has aperture priority or shutter priority modes.
Of course this option is going to cost you financially. If you don’t have the budget for this – read on.

2. Learn to live with your point and shoot and learn how to ‘trick it’ into doing what you want.

Ultimately you’ve got a digital camera that was designed largely to be used in Auto mode where it makes the decisions about what settings to choose.
Having said this – even the most basic entry level point and shoot digital cameras these days come with a variety of shooting modes which give you the photographer the ability to tell the camera what situation you’re shooting in and what type of photo you’re hoping to take.


The most common shooting modes include ‘sports’, ‘portrait’, ‘landscape’, ‘macro’, ‘movie’ (for more on shooting modes see this previous post).
Understanding and using these modes gives you a little more control over settings like Aperture and Shutter Speed as each of them will trigger different settings in your camera.
You write in your question that you’d like more control over Aperture and Depth of Field. I’d encourage you to shoot in two modes – ‘Portrait’ and ‘Landscape’.
  • If you’re looking for Shallow Depth of Field(ie your foreground and background blurry) shoot in Portrait mode as this will trigger your camera to choose a wider aperture.
  • If you’re looking for a wider depth of field(ie everything in focus) shoot in Landscape mode where the camera selects small apertures in this mode.
  • If you’re looking for a fast shutter speedchoose ‘Sports’ mode as in this mode it’s assuming you want to freeze fast moving subjects.
  • If you’re looking for a slow shutter speedyou’ll have more of a challenge as most cameras don’t have a an automatic mode that naturally chooses this. You could try shooting in Night mode (if your camera has it) but this mode will also fire off a flash. Try covering your flash up and you might get the result you’re after.
Of course none of these modes allow you to get specific about the settings your camera chooses but they do give you a bit more control than you might think you have.
If you’re still thirsting for more control, start saving for your next digital camera!

Aperture and Shutter Priority Modes



Over the last few weeks we’ve been looking at different elements of exposure and how to move out of the ‘Auto’ mode on your digital camera. We’ve looked atApertureShutter Speed and ISO and have discovered what each of them is and what impact changing them will have on your images.
Now that we’ve looked at the theory of how changing these elements impacts an image I’d like to move into how to use them by examining two shooting modes that many digital have on them that allow you to take a step away from the automatic settings that you might be spending a lot of time in.
The two shooting modes are Aperture Priority Mode and Shutter Priority Mode.

A Quick Reviser

We’re looked at how the three elements of the exposure triangle impact one another. This is particularly the case when it comes to aperture and shutter speeds. As you increase the size of your aperture (make the hole that you shoot through bigger) you let more light into your image sensor. As a result you will need a shorter shutter speed. In the opposite way if you increase the length of time your shutter is open you decrease the necessary aperture that you’ll need to get a well exposed shot.

Priority Modes

Aperture and Shutter Priority modes are really semi-manual (or semi-automatic) modes. They give you some control over your settings but also ensure you have a well exposed image by the camera making some of the decisions on settings. Let me explain each separately:

Aperture Priority Mode

(often it has a symbol of ‘A’ or Av’ to indicate it’s selected)
In this mode you as the photographer sets the aperture that you wish to use and the camera makes a decision about what shutter speed is appropriate in the conditions that you’re shooting in.
Dof
When would you use Aperture Priority Mode?– if you remember our tutorial on aperture you’ll see how the main impact that aperture had on images was with regards to Depth of Field (DOF). As a result most people use Aperture Priority Mode when they are attempting to have some control in this area. If they want a shallow DOF (for example in the shot to the right which has the flower in focus but the background nice and blurred) they’ll select a large aperture (for example f/1.4 – as in the example to the right) and let the camera choose an appropriate shutter speed. If they wanted an image with everything in focus they’d pick a smaller aperture (for example f/22) and let the camera choose an appropriate shutter speed (generally a longer one).
When choosing an Aperture keep in mind that the camera will be choosing faster or longer shutter speeds and that there comes a point where shutter speeds get too long to continue to hand hold your camera (usually around 1/60). Once you get much slower than this level you’ll need to consider using a tripod. Also if you’re photographing a moving subject your shutter speed will impact how it’s captured and a slow shutter speed will mean your subject will be blurred).

Shutter Priority Mode

(often has a symbol of Tv or S)
In this mode you as the photographer choose the shutter speed that you wish to shoot at and let the camera make a decision about what aperture to select to give a well exposed shot.
When would you use Shutter Priority Mode? – in our tutorial on shutter speed we talked about how the main impact of different shutter speeds was how ‘movement’ would be captured in your images. As a result most people switch to shutter priority mode when they want more control over how to photograph a moving subject.
For example if they want to photograph a racing car but want to completely freeze it so there is no motion blur they’d choose a fast shutter speed (say at 1/2000 like in the first shot below) and the camera would take into consideration how much light there was available and set an appropriate aperture. If instead you wanted to photograph the car but have some motion blur to illustrate how fast the car is moving you might like to choose a slower shutter speed (like the second shot below which has a shutter speed of 1/125) and the camera would choose a smaller aperture as a result.
1:2000-1
1:125-1
Keep in mind that as the camera chooses different apertures it will impact the Depth of Field in your image. This means if you choose a fast shutter speed to freeze your fast moving object that it’ll have a narrower DOF.

Practice

As you can see – Shutter and Aperture Priority modes do give you more control over your images but they do take a little practice to get used to.
As you use them you need to not only think about the setting that YOU set but also keep an eye on the setting that the camera selects for you.
I find that when shooting in Av or Tv modes that it’s often best to bracket your shots and shoot a number of images of the same subject (where you have time) at different settings. This will ensure that you’re likely to get at least one shot which meets your need.
The best way to learn about Shutter priority and Aperture Priority modes is to grab your camera, to head out with it and to experiment. Switch to Av or Tv and start playing with the different settings (taking lots of shots as you go). Particularly watch how the camera makes changes to compensate for your selections and what impact it has upon the shots that you take.
In Aperture Priority Mode take some shots at the largest aperture you can (small numbers) and see how it blurs the background (but also increases the shutter speed) and then head to the other end of the spectrum to take some shots at the smallest aperture you can (large numbers) to see how it keeps more of your image in focus.
In Shutter Priority Mode play with fast and slow shutter speeds and see how that impacts DOF.
Don’t be frustrated if your initial shots are not what you’d expect – it takes practice to get your head around these modes. But keep in mind that when you do master them you’ll have a lot more creative control over your shots. It’s really worth learning this.

Introduction to White Balance

White Balance is an aspect of photography that many digital camera owners don’t understand or use – but it’s something well worth learning about as it can have a real impact upon the shots you take.
So for those of you who have been avoiding White Balance – let me introduce you to it. I promise to keep it as simple as possible and keep what follows as useable as I can:
At its simplest – the reason we adjust white balance is to get the colors in your images as accurate as possible.
Why would you need to get the color right in your shots?
You might have noticed when examining shots after taking them that at times images can come out with an orange, blue, yellow etc look to them – despite the fact that to the naked eye the scene looked quite normal. The reason for this is that images different sources of light have a different ‘color’ (or temperature) to them. Fluorescent lighting adds a bluish cast to photos whereas tungsten (incandescent/bulbs) lights add a yellowish tinge to photos.
White-Balance
The range in different temperatures ranges from the very cool light of blue sky through to the very warm light of a candle.
We don’t generally notice this difference in temperature because our eyes adjust automatically for it. So unless the temperature of the light is very extreme a white sheet of paper will generally look white to us. However a digital camera doesn’t have the smarts to make these adjustments automatically and sometimes will need us to tell it how to treat different light.

So for cooler (blue or green) light you’ll tell the camera to warm things up and in warm light you’ll tell it to cool down.

Adjusting White Balance

Different digital cameras have different ways of adjusting white balance so ultimately you’ll need to get out your camera’s manual out to work out the specifics of how to make changes. Having said this – many digital cameras have automatic and semi-automatic modes to help you make the adjustments.

Preset White Balance Settings

Here are some of the basic White Balance settings you’ll find on cameras:
  • Auto– this is where the camera makes a best guess on a shot by shot basis. You’ll find it works in many situations but it’s worth venturing out of it for trickier lighting.
  • Tungsten– this mode is usually symbolized with a little bulb and is for shooting indoors, especially under tungsten (incandescent) lighting (such as bulb lighting). It generally cools down the colors in photos.
  • Fluorescent– this compensates for the ‘cool’ light of fluorescent light and will warm up your shots.
  • Daylight/Sunny– not all cameras have this setting because it sets things as fairly ‘normal’ white balance settings.
  • Cloudy– this setting generally warms things up a touch more than ‘daylight’ mode.
  • Flash– the flash of a camera can be quite a cool light so in Flash WB mode you’ll find it warms up your shots a touch.
  • Shade– the light in shade is generally cooler (bluer) than shooting in direct sunlight so this mode will warm things up a little.

Manual White Balance Adjustments

In most cases you can get a pretty accurate result using the above preset white balance modes – but some digital cameras (most DSLRs and higher end point and shoots) allow for manual white balance adjustments also.
The way this is used varies a little between models but in essence what you do is to tell your camera what white looks like in a shot so that it has something as a reference point for deciding how other colors should look. You can do this by buying yourself a white (or grey) card which is specifically designed for this task – or you can find some other appropriately colored object around you to do the job.
I’ve done this with the following two shots.
The first shot is one of some books on my wife’s bookshelf taken in Auto White Balance mode. The light in my room is from three standard light bulbs and as a result the image is quite warm or yellow.
Auto
After taking this picture I then held up a piece of white paper to my camera to tell it what color white is. Then I took a second shot with this setting and got the following result – which you’ll see is a much truer color cast than the first image.
Custom-White-Balance
This manual adjustment is not difficult to do once you find where to do it in the menu on your camera and it’s well worth learning how to do it.

Digital Camera Modes


This week I did an informal survey on a few of my digital camera owning friends and asked them to nominate which shooting modes that they most commonly use on their digital cameras (they use a range of point and shoot and DSLR digicams).
The results of this little survey didn’t really surprise me – Automatic Mode was the overwhelming response from both beginner and the more advanced users alike (a little surprising to me). In fact three of the people I questioned responded by asking ‘is there any other non Automatic mode?’
As a result I’ve decided to take a run through the basic shooting modes that most digital cameras have (both point and shoot and DSLRs have most of these).
While this is pretty basic information for many readers I hope it will be helpful for those right at the beginning of their digital photography journey who are yet to venture out of Automatic Mode.

Automatic Modes

Automatic Mode

I suspect no one will need any introduction to this mode (as it seems most digital camera owners use it). Auto mode tells your camera to use it’s best judgement to select shutter speed, aperture, ISO, white balance, focus and flash to take the best shot that it can. With some cameras auto mode lets you override flash or change it to red eye reduction. This mode will give you nice results in many shooting conditions, however you need to keep in mind that you’re not telling your camera any extra information about the type of shot you’re taking so it will be ‘guessing’ as to what you want. As a result some of the following modes might be more appropriate to select as they give your camera a few more hints (without you needing to do anything more).

Portrait Mode

Portrait-Mode-1








When you switch to portrait mode your camera will automatically select a large aperture (small number) which helps to keep your background out of focus (ie it sets a narrow depth of field – ensuring your subject is the only thing in focus and is therefore the centre of attention in the shot). Portrait mode works best when you’re photographing a single subject so get in close enough to your subject (either by zooming in or walking closer) so that your photographing the head and shoulders of them). Also if you’re shooting into the sun you might want to trigger your flash to add a little light onto their face.

Macro Mode


Macro-1





Macro mode lets you move your closer into your subject to take a close up picture. It’s great for shooting flowers, insects or other small objects. Different digital cameras will have macro modes with different capabilities including different focussing distances (usually between 2-10cm for point and shoot cameras). When you use macro mode you’ll notice that focussing is more difficult as at short distances the depth of field is very narrow (just millimeters at times). Keep your camera and the object you’re photographing parallel if possible or you’ll find a lot of it will be out of focus. You’ll probably also find that you won’t want to use your camera’s built in flash when photographing close up objects or they’ll be burnt out. Lastly – a tripod is invaluable in macro shots as the depth of field is so small that even moving towards or away from your subject slightly can make your subject out of focus. (I’ll write a full tutorial on Macro Photography in the coming weeks).

Landscape Mode

Landscape-Icon-1




This mode is almost the exact opposite of portrait mode in that it sets the camera up with a small aperture (large number) to make sure as much of the scene you’re photographing will be in focus as possible (ie it give you a large depth of field). It’s therefore ideal for capturing shots of wide scenes, particularly those with points of interest at different distances from the camera. At times your camera might also select a slower shutter speed in this mode (to compensate for the small aperture) so you might want to consider a tripod or other method of ensuring your camera is still.

Sports Mode

Sports-Icon-1




Photographing moving objects is what sports mode (also called ‘action mode’ in some cameras) is designed for. It is ideal for photographing any moving objects including people playing sports, pets, cars, wildlife etc. Sports mode attempts to freeze the action by increasing the shutter speed. When photographing fast moving subjects you can also increase your chances of capturing them with panning of your camera along with the subject and/or by attempting to pre focus your camera on a spot where the subject will be when you want to photograph it (this takes practice).

Night Mode

Night-1




This is a really fun mode to play around with and can create some wonderfully colorful and interesting shots. Night mode (a technique also called ‘slow shutter sync’) is for shooting in low light situations and sets your camera to use a longer shutter speed to help capture details of the background but it also fires off a flash to illuminate the foreground (and subject). If you use this mode for a ‘serious’ or well balanced shot you should use a tripod or your background will be blurred – however it’s also fun to take shots with this handheld to purposely blur your backgrounds – especially when there is a situation with lights behind your subject as it can give a fun and experimental look (great for parties and dance floors with colored lights).

Movie Mode

Movie-2






This mode extends your digital camera from just capturing still images to capturing moving ones. Most new digital cameras these days come with a movie mode that records both video but also sound. The quality is generally not up to video camera standards but it’s a handy mode to have when you come across that perfect subject that just can’t be captured with a still image. Keep in mind that moving images take up significantly more space on your memory storage than still images.
Other less common modes that I’ve seen on digital cameras over the past year include:
  • Panoramic/Stitch Mode– for taking shots of a panoramic scene to be joined together later as one image.
  • Snow Mode– to help with tricky bright lighting at the snow
  • Fireworks Mode– for shooting firework displays
  • Kids and Pets Mode– fast moving objects can be tricky – this mode seems to speed up shutter speed and help reduce shutter lag with some pre focussing
  • Underwater Mode– underwater photography has it’s own unique set of exposure requirements
  • Beach Mode– another bright scene mode
  • Indoor Mode– helps with setting shutter speed and white balance
  • Foliage Mode– boosts saturation to give nice bold colors

Semi Automatic Modes

Aperture Priority Mode (A or AV)

This mode is really a semi-automatic (or semi-manual) mode where you choose the aperture and where your camera chooses the other settings (shutter speed, white balance, ISO etc) so as to ensure you have a well balanced exposure. Aperture priority mode is useful when you’re looking to control the depth of field in a shot (usually a stationary object where you don’t need to control shutter speed). Choosing a larger number aperture means the aperture (or the opening in your camera when shooting) is smaller and lets less light in. This means you’ll have a larger depth of field (more of the scene will be in focus) but that your camera will choose a slower shutter speed. Small numbers means the opposite (ie your aperture is large, depth of field will be small and your camera will probably choose a faster shutter speed).

Shutter Priority Mode (S or TV)

Shutter priority is very similar to aperture priority mode but is the mode where you select a shutter speed and the camera then chooses all of the other settings. You would use this mode where you want to control over shutter speed (obviously). For example when photographing moving subjects (like sports) you might want to choose a fast shutter speed to freeze the motion. On the flip-side of this you might want to capture the movement as a blur of a subject like a waterfall and choose a slow shutter speed. You might also choose a slow shutter speed in lower light situations.

Program Mode (P)

Some digital cameras have this priority mode in addition to auto mode (in a few cameras Program mode IS full Auto mode… confusing isn’t it!). In those cameras that have both, Program mode is similar to Auto but gives you a little more control over some other features including flash, white balance, ISO etc. Check your digital camera’s manual for how the Program mode differs from Automatic in your particular model.

Fully Manual Mode

Manual Mode

In this mode you have full control over your camera and need to think about all settings including shutter speed, aperture, ISO, white balance, flash etc. It gives you the flexibility to set your shots up as you wish. Of course you also need to have some idea of what you’re doing in manual mode so most digital camera owners that I have anything to do with tend to stick to one of the priority modes.

Understanding Histograms

Histogram




“I was flicking through my camera’s menu today and came across a little graph labeled ‘histogram’. What is it and should I take any notice of it? Is there such a thing as the ideal histogram? What should we be aiming for?” – Brent

What is a Histogram

Histograms are a topic that we could (and probably should) spend a lot of time talking about but let me give you a very brief answer to get you through in the short term.
Histograms are a very useful tool that many cameras offer their users to help them get a quick summary of the tonal range present in any given image.
It graphs the tones in your image from black (on the left) to white (on the right).
The higher the graph at any given point the more pixels of that tone that are present in an image.
So a histogram with lots of dark pixels will be skewed to the left and one with lots of lighter tones will be skewed to the right.
The beauty of a histogram is that the small LCD display on your camera is not really big enough to give you an great review of a picture and you can often get home to find that you’ve over or under exposed an image. Checking the histogram can tell you this while you’re in a position to be able to adjust your settings and take another shot.

Some Examples of Histograms

Let’s look at a couple of examples of histograms on shots I’ve taken over the first year of my son’s life (it’s his birthday this week so we’re going through some shots).
Compare these two shots and their corresponding histograms:
4-1Histogram-4-1
The above shot has a lot of light tones – in fact there are parts of the shot that are quite blown out. As a result on the right hand side of the histogram you can see a sudden rise. While there are quite a few mid tones – everything is skewed right and with the extreme values on the right hand side indicate an over exposed shot.
5-1Histogram-5
This second shot has a lot of dark tones. This is partly because of the black and navy clothes in the shot – but also because it’s slightly underexposed shot. The resulting histogram is quite different to the first one – the values are skewed to the left hand side.

Is there such a thing as a ‘good’ histogram?

As with most aspects of photography, beauty is in the eye of the beholder and there’s always a lot of room for personal taste and different ways of expressing yourself as a photographer.
There is no such thing as the ‘perfect’ histogram – different subjects and photographic styles will produce different results. For example taking a silhouette shot might produce a histogram with peaks at both ends of the spectrum and nothing much in the middle of the graph. Taking a shot of someone at the snow will obviously have a histogram with significant peaks on the right hand side…. etc
Having said this (and to generalize) – in most cases you’ll probably want a fairly balanced shot with a nice spread of tones. Most well exposed shots tend to peak somewhere in the middle and taper off towards the edges.

Using Histograms While Shooting

So now you know what a histogram is – grab your digital camera’s manual and work out how to switch it on in playback mode. This will enable you to see both the picture and the histogram when reviewing shots after taking them.
Keep an eye out for histograms with dramatic spikes to the extreme ends of either side of the spectrum. This indicates that you have a lot of pixels that are either pure black or pure white. While this might be what you’re after remember that those sections of the image probably have very little detail – this is a hint that your image could be either over or under exposed.
The histogram is really just a tool to give you more information about an image and to help you get the effect that you want. Having your camera set to show you histograms during the view process will tell you how your image is exposed. Learning to read them will help you to work out whether you’re exposing a shot as you had hoped.

Another Example of a Histogram

Lets finish this tutorial by looking at one last example of a histogram:
1-1Histogram-1-1
You can see in this shot a much more even spread of tones. It’s still not perfect and I’d do a little post production work but it’s a much more evenly exposed shot and the histogram reflects this.

Pre-Focus to Combat Shutter Lag


My first foray into digital photography was with a small Canon point and shoot camera. I immediately fell in love with the medium due to being able to take large amounts of shots at no cost, being able to see shots immediately after taking them and the ease at which I could use the images in different ways.
However there was one one aspect of digital photography that I immediately began to hate – shutter lag.
In the first few shots that I took with my new point and shoot I realized that pressing down the shutter release didn’t mean that the scene that I was looking at would be captured just the way I saw it – there was at least a 1 second delay before the shot was taken.
Most modern day digital cameras have cut down the annoying shutter delay/lag problems significantly. In fact the only camera that I’ve tested with any significant lag has been my new camera phone (the Nokia N95 – which has a 5 megapixel camera in it – but which is annoyingly slow to use). Most point and shoot cameras these days will not have a noticeable shutter lag, however I still get asked about it a lot.
One of the reasons that I suspect many still think they suffer from shutter lag is that they don’t allow the camera time to focus. I realized this earlier in the week when out with a point and shoot user and watching their technique. They would see a scene – lift the camera to their eye and immediately hit the shutter in one jerking movement – expecting an instantaneous result.
Of course the camera needed a moment to focus and the resulting small delay while it did so was labeled ‘shutter lag’ by my friend.
If you’re wanting to capture a moment in timed to the smallest delay possible it’s worth pre-focussing your camera on the scene – before you want to take the shot.
The way to do this is to frame the scene and then push your shutter release down half way. Once you’ve done this – continue to hold down the shutter release half way down until the moment you want to capture the scene – when you’ll press the shutter the rest of the way.
I showed my friend this simple technique and he was amazed at how exact he could get the timing on his point and shoot camera. His ‘shutter lag’ was gone – all he needed to do was learn about pre-focussing.

Using EXIF Data

I promised when I started this site that I’d do my best to keep it as untechnical and jargon free as possible. Having said this – today I want to use a term that I doubt many beginner digital photographers would be familiar with. Having said this it’s not a complicated concept and one that is very useful.
The term I want to unpack today is EXIF data.
EXIF stands for ‘Exchangeable Image File’ data and it is the information that your camera stores with you image file that tells you about it. It is stored when you take images in JPEG format (or TIFF). Almost all camera manufacturers support EXIF and whether you know it or not your camera is likely to be recording it with your image file.
Perhaps the best way to talk about it is to show you the EXIF data associated with a picture I took this morning of my son (any excuse to show him off). Here’s the shot:
X

The EXIF data associated with this picture can be found in a number of ways.
1. Firstly if the image is still stored on a memory card in my camera I can view it there. On my Canon DSLR I do this by hitting the ‘info’ button while in preview mode. It will then give me an array of information about the image including shutter speed, aperture, date and time of shot etc.
2. Another way to look at an image’s EXIF data is to right click an image file and clicking ‘properties’ (if you’re on a Mac click ‘get info’. Here’s what I get when I do that on this image on my Mac:
Exif-2
It doesn’t show all of the EXIF data but does gives some good basic information.
3. The last way of viewing EXIF data that we’ll talk about is via your image editing software. I’m using Photoshop Elements 2.0 today (for Mac) so in this software I go to the ‘File’ menu then choose ‘File Info’. This allows me to view two types of information about the image ‘general’ and ‘EXIF’. When i choose the EXIF option I get this:
Exif
You can now see some of the information about the image taken including what camera I was using, the resolution, the time and date of the shot, the shutter speed, ISO and aperture and if I scroll down it will even tell me what focal length I was using (105mm).
You will find different cameras and different photo editing programs will mean that the EXIF data displayed will vary (older cameras stored less information) but most will give you the basics of your shot.
EXIF data is very useful for a variety of reasons – the main one being that it allows a photographer to compare shots to find out what I did right and wrong in them.
For example I might look at the image above and think to myself ‘gee I wish I’d had a larger depth of field and had not only the hand but the face in focus’. I could then look at the aperture f/4.0 and see that next time if I want bigger depth of field that I should use a smaller aperture (f/5.6 or more). Similarly I might look at the ISO and think it was too grainy and see it’s at 400 and could have perhaps been pulled back to 200.
Using EXIF data is probably not something you’ll do with every image but especially when you’re starting out in digital photography it’s a worthwhile feature to play around with and to keep in mind as you seek to improve your photography.

Automatic Exposure Bracketing (AEB)

Have you ever been photographing a subject with tricky lighting or lots of variation between bright and darker areas but were not sure what exposure setting to go with?
One way to work in such situations is to manually play around with your exposure control and take a series of shots – the problem with this is that it takes time and if you are photographing a changing environment (for example a sunset which changes from moment to moment) you can lose ‘the moment’ while you get things right.
Most DSLRs (and some more advanced compact cameras) come with a feature called ‘Automatic Exposure Bracketing‘ (AEB) which can be useful to learn how to use in such situations.
By selecting it you can quickly take three shots (usually three) at different exposures without having to manually change any settings between frames. You can see an example of this below
Aeb-Over-ExposedAeb-NormalAeb-Under-Exposed
When you select Automatic Exposure Bracketing the camera will choose one exposure (based upon what its metering thinks is right) and then it will take one other shot on either side of this best guess (one over exposed (as in the left shot above) and one underexposed (as in the right shot above)).

This way you end up with the three images in a series with exactly the same composition but at different exposures for you to select the best of later on.
If you have the camera in burst mode (continuous shooting) the three shots will be taken if you hold down the shutter for a burst of three shots. If you’re in single shot mode the shots will take as you depress the shutter three times.
Each digital camera has a different way of selecting AEB, some like Nikon’s D70 have an accessible button on the back (marked BKT) while others (like Canon) have an AEB setting in their menus.
Check out your manual to see how AEB works on your digital camera. Most will allow you to change the variation between shots by different ‘stops’. For example you might want a big variation between your three shots and would select a ‘2 stop’ gap or you might only want a slight variation and choose a ‘half stop’ gap. I generally start with a ‘1 stop’ variation and work from there.
PS: to give you a little more control in Automatic Exposure Bracketing mode you can use it ether in Aperture Priority Mode or Shutter Priority Mode. Using AEB in Aperture Priority mode will all you to choose the aperture you want for the shot and telling the camera to make the variations in shots by varying shutter speed. Alternatively using AEB in shutter priority mode will keep the shutter speed at the speed you select and tell the camera to vary the exposure by changing the aperture in your shots.