Thursday, April 09, 2009

Digital Camera Guide Part 4

So along with knowing what to look for in a camera, you should now hopefully now why your camera insists on focusing on odd things, why the background is sometimes blurry or why your entire photo appears speckly or bleached out.

You've also taken Dan's advice a got a book from the library and now know more than you perhaps ever wanted to know about focal distances etc. but the photos you take still lack pizazz or just aren't that great; what to do?

No Film

The first thing to ram home, especially to those used to film cameras, is the only limit to the number of photos you can take is the size of your memory card. On a 512Mb card I can take around 250 photos before filling it up; a huge magnitude of difference over film. To put that into context I can take a shot roughly every five minutes for an entire day. If get into the habit of keeping spares and I had two 2Gb cards that's 2000 photos that's roughly one a minute for an entire day. And with cards being both cheap and reusable there's no excuse not to have spares.

To put it bluntly don't be scared of taking lots of shots, and thus don't be scared of playing with the settings to take lots of different shots.

Built-in Settings

Almost every camera has an array of different modes - ranging from Portrait to Sport to Underwater or Snow. These settings can be a great time saver, but to use them effectively it's good to know what they're doing.

What they are doing is two things - firstly they're weighting all those settings from Part 3 in particular directions, and secondly they might be affecting the post-processing that the image receives before it's saved.

So let's take Portrait. The base assumption is that you're taking a shot of something that might be moving a little, and that you're only really interested in what the camera's pointing at. So ramp down the multi-point AF so it's not trying to focus over too great a distance which means you can have a larger aperture which in turn allows a fast shutter speed.

For Landscape that'd be reversed - a small aperture to keep everything in focus and a slow shutter speed because nothing should be moving about.

For Sport you need to weight heavily towards a fast shutter speed to freeze the action.

For Snow you need to reset the White Balance (I'll deal with that later) to make the snow appear white and not blue.

Despite the names given to them once you understand what they try to do they can be a quick time-saver if you're taking a shot that simply requires those sort of settings.

Practice with the modes, and of course, if in doubt take more than one shot.


The two defaults are Landscape or Portrait (wider or taller). The names themselves should be a give-away as to when to use them, but put simply if you want to emphasize the width you use landscape; the height, portrait. Oft times you don't have a choice, if you're taking a group shot you want as much detail as possible while keeping everyone in shot; unless they're all climbing a ladder they'll be aligned horizontally so that's the shot to take.

Remember the first point though - if in doubt take at least one of each.

Something's askew

Dan's looked at what he refers to as the horizon problem, but while this shows up more prominently on landscape shots it can be a problem with every shot you might take.

The difficulty is that when looking at a scene with the screen it's easy to adjust the levels of objects to align with the sides of the screen. When you use the viewfinder those guides disappear and, of course, with regard to your own point of view the horizon is always level even if the camera isn't.

If the viewfinder has markings you can try to use these, if the camera allows you might be able to buy different eyepieces with guides inscribed on the glass.

Without these the only advice available is practice and to take a small pause for thought when lining up a shot as to is this level. [Hmm as an aside wouldn't a viewfinder with a couple of small spirit-levels built-in be an excellent idea?]

If in doubt review your shot after you've taken it and if you're not happy take another if possible.

[Additional - I'll add in White Balance too

Weird colours

Sometimes you'll find your photos have what is known as a colour cast, they appear slightly blue, or red. In most cases you'll find this is because the camera can't decide what white is. This may seem a rather stupid thing not to know, but this is because there is normally a colour cast on everything around us depending on the type of light shining on it. Our wonderful brains can usually just compensate for it; cameras can have more difficulty.

If you delve into the menu selection (and you should) you might find an option labelled White Balance. For the most part it's a pick-an-option of various different types of light - Outdoor, Tungsten etc; sometimes you can get a temperature chart up and pick your own colour manually. One of the quickest methods of dealing with colour cast is if you have a semi-manual option - essentially you can pick this, point it at something you know is white and confirm this with the camera; it'll have a little "Oh so that's what white looks like" moment and will compensate for any other shots you take from that point on.

For fun times try picking a white balance that doesn't match the current conditions and see how it affects the colour of the picture you've taken.

Action Shots

As mentioned for the Sports mode to freeze the action requires a fast shutter-speed. This is also where shutter lag really starts to show its hand. Like all things practice. If you know it takes this long between pressing the button and getting a shot anticipate the movement and take the shot when you know the object will be where you want it once the camera fires.

Perhaps you don't want to freeze the action completely and want some motion blur. Well in that case slow the shutter down or pan the camera as you take the shot.

The flash might help, using a slow shutter with a flash may give you a frozen image with motion blur. Check the settings and see if you can have the flash fire just as the shutter is closing it's usually headed Second Curtain. However consider the subject's reaction to having a light flare at them and obey any rules governing flash photography.

[Additional - Another option is to change the drive-motor settings. Normally you click the shutter button and get one shot, however it may be possible to change that such that the camera continues to take shots while the button is depressed. Depending on how quickly it can take shots in succession doing so with a fast subject gives a better chance that at least one will look good]

Once again practice and take plenty of shots

The problem that may arise with action shots is keeping the subject in focus this is where pre-focussing comes into play.


As per Part Three and the bit about focusing, the camera will try to auto focus if you half-press the shutter button. If you keep that pressed at that level you can now move the camera and the focus will remain where it was - this is focus lock.

What that means is that if you're using manual focus or centre AF then the object you're focussing on no longer needs to be at the centre of the frame.

For the astounding bush this means I can centre AF using the bush, keep the shutter button half depressed and re-frame the shot so the bush appears in the top right corner. Provided the distance between it and the camera is still within the depth of field measurement the bush will remain in focus.

So as previously mentioned this can aid keeping focus for taking photos of moving objects. If you know roughly the distance the moving object is going to be away from you when you want your shot then you can pre-focus the shot using something at the same distance that's not moving. When the object appears you can simply depress the shutter fully and the object should be in focus.

I know you're probably getting tired of hearing this, but practice and take plenty of shots.

Going back to the amazing bush why would I want to have it appear top right anyway.


You can find a plethora of information about compositional techniques, I'll deal here with the simplest - The Rule of Thirds. I say Rule, but it should be Guide, doesn't have the same portentous ring to it though.

The Rule of Thirds involves splitting up the view into nine three-by-three equal sections. The majority of cameras allow these guidelines to be displayed on screen, sadly they're unlikely to appear on the viewfinder unless you can buy and change it.

Not only do they help you keep things levelled and avoid skew, but they can aid with basic composition as to where the subjects should be placed.

To make it simple subjects of interest should appear on a line, or better yet at a point the lines cross. So your horizon should fall along the top or bottom vertical lines, in your group shot the people's feet should be on the bottom line while their heads should cross the top one.

So with my bush I focus-lock on it then move it to the top-right junction of the two lines to see if that looks better.

As I've said the Rule is really a Guide it can help, but there's no need to stick slavishly to it.

Yeah yeah practice, take lots of shots; you should know the drill by now.

Funny Angles

Just because you're standing up and facing forward doesn't mean that the photos you take have to correspond to that stance. What would the shot look like if the camera was above your head or sitting at your feet? If you have an adjustable screen taking shots you wouldn't normally be able to judge becomes much easier, but without then the first adage applies - take lots of shots.

Don't be scared of kneeling down or holding the camera up in the air. Use objects around you to stand on, within legal limits and considering safety of course. Don't think that the shot you can see as you stand there is the best one available. This applies to every shot - with a close group everyone takes a shot at the same height, what would it look like if the camera was above the group with them all looking up, how about from lower down and further away?

You may think you might look a prat crouching down in public or putting your camera on the ground, but sometimes it's the only way to get the best angle and to be blunt who cares?

Have fun and don't limit yourself to simply what you can see from your point of view.

Use of objects

As just mentioned you can use your surroundings to get a different view on things, but you should also consider anything around you to be a steadying post. Although we can eliminate shake with shutter speed and image stabilisation [and a tripod] there's no harm in bracing yourself or the camera against something solid when you take your shot. You never know doing so may produce an angle on something you didn't even consider.

[Additional - Again the drive-motor settings may play a part here, that includes setting a time delay so you can put the camera down then have it take a photo so as not to introduce any movement as you press the shutter button]


Unless you're in a studio under controlled conditions you've pretty much got to work with what you're given. But look how shadows fall, what is and isn't being shown, and where the light source is. Sometimes you can work with what's there and sometimes you just get lucky.

Bringing it together

So my imaginary bush. A path runs away from me and passes to the left of the bush before turning away to the right. The skyline is pretty bare and unimpressive and the sky cloudy, but still reasonably bright.

I'm going to take a shot of both the bush and path and try to minimise the skyline. I want to emphasize the length of the path so I'm going to take the shot in the Portrait orientation. I only want the bush in focus so I set a wide-ish aperture to decrease depth of field and keep a fast shutter. As the bush is the main focal point I now focus-lock on that with the centre AF. I want the path in shot so with focus-lock I move the camera so the bush is top right at the junction of the two lines for rule of thirds. I'm not happy about how much path is showing so I kneel down keeping the camera at the same distance from the bush to keep it in focus. Looking at the path I see if I slide sideways slightly one side of the path will appear to start at the bottom right of the frame; crouch down a little further and the other side will intersect a line and the bottom edge. Check that looks fine and snap.

Of course all this may seem fine and good if you've got the time to set things up and check it, but if you keep doing it all these things start to become second nature. You'll already see what settings you want, and the best angle to take it from and from there it's a quick set and only minor shuffling to get the shot you want.

Oh and of course if you do have the time then practice with the settings and take lots of shots; last time I'll say that I promise.


Orphi said...

You've been busy.

Tell you what. How about I show you some pictures I took, and you tell me why they ended up looking awful? ;-)

FlipC said...

So have you I see.

But hey yeah I'd like to see your photos and tell you why they're not as awful as you think ;-)

Have you got a Flickr account (or similar) or are you going to link from your blog?

Orphi said...

Well, let's take a look at some of my pictures which are already linked, shall we?

After several hours of Googling, it turns out it's actually quite difficult to get Google to find really high-quality photographs. It seems most of the images on the Internet are from clueless amatures like me, rather than hardened professionals. But I did find a few images which demonstrate my point.

Take a look at, for example, this image. Notice how the foreground is completely white. (It should be brown.) Note how the entire scene utterly lacks colour, is cold and flat, and basically looks amaturish. Similarly here.

Now compare that to this, this, this or even this. Note that in all cases, we have glorious, delicious deep saturated colours. The trees and the grass are solid green. The bark is a strong red. The sky is deep blue.

Now take a look at this. Can you tell what colour those flowers are? Hint: not white. It hardly compares to the likes of this or this or even this, does it? The colour and the composition is nowhere near as good. Obviously cowslips aren't hugely colourful to start with, but the leaves could at least be green and the earth brown.

As you can see here, my camera stubbornly refuses to photograph small objects in focus. (I'm not sure if that's a limitation of the actual focal length of the lense or just the autofocus software.)

What the hell is going on here, eh? There's more broken flowers (these ones are vivid yellow IRL). Check out this really interesting tree stump, rendered utterly flat by my photography.

Would you like me to continue?

Dan H said...

Continuing would be unnecessary. All of the pictures you've identified as having colour problems in fact have one problem: they are all overexposed. Remember that a camera has three sensors for each pixel: red, green, and blue. Each sensor 'maxes out' at a particular illumination. If your flower illuminates the red sensor twice as much as the blue sensor, you get a sort of pinky colour. But if too much light reaches the sensors, so that all three max out, all you get is white. Overexposure and underexposure are responsible for most problems with white regions of the image, particularly white skies, and for images looking flat. When the problem is severe enough to make colours look white or black, you can't correct for it in a photo editor afterwards: the information of what colour the object actually was is simply not present in the image. The only solution is to expose the shot correctly, check it on the screen, and if it's wrong, adjust the exposure compensation and take it again.

The correct exposure of your image is calculated by the camera - on a compact, it often uses a separate light sensor on the front of the camera, which you have to be careful not to obstruct with your fingers; on a better camera it actually uses the light coming through the lens (TTL). With TTL metering it might have different modes like "centre-weighted", "full frame", or "spot", and you should try taking shots with all of these modes to see the effect. But often the camera will screw it up completely, because the dynamic range - the difference between the darkest and lightest parts of the shot - is too much for the sensor, and it doesn't know (or guesses wrong) which area is most important.

Exposure compensation is the tool the camera gives you to correct its mistakes in guessing exposure. The button is usually labelled something like "AE +/-" or "EV +/-". Turning it up makes the camera take a brighter picture, and turning it down makes the camera take a darker picture. After you've used your camera in different situations and sighed at the poorly exposed images you get, you start to get a feel for how the software in the camera works, and in what circumstances it's going to make the wrong decision. For instance, I know that my camera often overexposes shots with lots of cloud in them - cloud is much brighter than it looks - so if I'm taking a picture like that, I'll turn the exposure down a stop.

Seriously, this kind of advice is exactly what the book you get from the library gives you, with examples of photos done wrong and what they look like done right. If you really want to produce better images with your camera instead of just claiming to be useless, go to the library and get a photography book, or go to Amazon and spend less than the price of even the cheapest camera on a photography book.

Orphi said...

“All the problems are due to overexposure.”

Well, except for the small objects that won't focus. ;-)

I find it kind of ironic that the camera refuses to work without copious amounts of light, and yet on this bright, sunny day, it's actually managed to overexpose things. (Usually almost every shot is seriously underexposed.)

Is there a reason why even the parts that aren't overexposed have a blue tint? I'm pretty sure sunlight is yellow, not blue.

As for correcting it, I've found that even if an image is nearly black or nearly white, trying to correct the colours afterwards is a hopeless exercise. There's too little precision left to produce any kind of worthwhile image. As you say, the only solution is to get a correct exposure in the first place.

Of course, that's kind of the problem, isn't it? From the pitiful LCD on my camera, it's impossible to tell what colour balance an image has. Tilt the screen a fraction of a degree and all the colours change anyway. (It's similarly impossible to tell if anything is in focus. The resolution is far too low.) I'm not really sure what kind of a camera could fix this problem.

As for adjusting the camera… it's news to me that you can actually do this. Hunting around the menus reveals a setting to control how many megapixels you get, but nothing else.

However, in the last few minutes, I have discovered that if you rotate the little dial that I never touch from “A” to “M”, two new menu items appear. One appears to be exposure, and the other is white-balance. Both give me a handful of presets to choose.

Changing the white-balance makes the display change instantly, which is nice. Basically it seems to adjust how blue the image is.

Irritatingly, changes to the exposure setting have no immediate visible effect. However, I took some shots of the back of my hand, and it seems turning the exposure to the lowest possible setting does make the image darker than the default. Turning it up doesn't appear to have any effect, which is a little odd.

Well there we are then. Two new settings that I never knew my camera had. Maybe fiddling with the white-balance could have made my shots a little less blue. But short of taking every shot 6 times (i.e., shooting it with all possible exposure settings), I'm not sure how to get a decent exposure value.

As for getting a book — as a matter of fact, I already own one. But it jabbers on about bokah and colour spaces and RAW format and so on and makes no sense at all to me.

FlipC said...

Dan I agree all the shots shown are over-exposed, however as Orhpi has said before and just now is that his camera seems to also be prone to underexpose. This suggests the camera just can't grasp how much light is around; this is why I mentioned the EV setting when I was adjusting is photo in my other entry.

Orphi - glad you found that setting. From the manual it appears you have a small ability to alter the aperture, the exposure and the white balance. The white balance as I mentioned in um part 3/4? is to deal with exactly the colour cast problem you've been experiencing.

As for the book, yeah to an extent this is why I tried to write what I have and keep it as simple as possible.

Orphi said...

I don't think anybody is debating that the pictures in this series are overexposed; that seems fairly obvious. The question is just “why?” Similarly, why the blue tint? I can probably remove it, but why is it there in the first place?

As for the camera's sensitivity, I just note that when you look at the LCD just before taking a shot, the image almost always comes out very dark unless you have intense illumination of whatever you're pointing the camera at. The autofocus also stops working unless you have such illumination.

(Take a look at this image for an example of an image which is, IMHO, under-exposed. Presumably because of the sky? I would have thought it would be possible to do better than this, even with the amount of sky though.)

I doubt owning a more expensive camera is going to solve the problem that I tend to photograph very boring objects, or that sometimes it's impossible to stand far back enough to get everything in shot. But I'm sincerely hoping that a better camera won't constantly eat batteries and will work properly in lower lighting conditions. That would be something…

FlipC: Maybe you would publish a short summary. For example, I recall that apature and DoF are related, but off the top of my head I can't remember which way round. (I.e., does a small apature give you a large or a small DoF?)

Dan H said...

"As for the camera's sensitivity, I just note that when you look at the LCD just before taking a shot, the image almost always comes out very dark unless you have intense illumination of whatever you're pointing the camera at. The autofocus also stops working unless you have such illumination."

In low light, often the camera will use a slower shutter speed to let more light in, but when it has to operate the sensor continuously to keep the screen updated, it can't vary the shutter speed, so the picture will be darker. That's another advantage of using the viewfinder to compose your shot. The autofocus uses the image the sensor is continuously recording to find the optimum focus, by varying the focus until the contrast of the shot is at its greatest (which indicates that edges are sharper), so again, that's why it doesn't work in low light.

The sky in the image you link is pretty decently exposed: the camera doesn't realise that you're trying to expose for the foreground objects, which take up less than half the frame. As I mentioned, setting the autoexposure mode to "AF point" or "centre-weighted" might have given you a better shot in that case.

"I doubt owning a more expensive camera is going to solve the problem that I tend to photograph very boring objects..." No, that's something you can only change by practising more, regardless of what camera you have. You have to learn to take shots within the limitations of the equipment. "...or that sometimes it's impossible to stand far back enough to get everything in shot." Well, with an SLR, you have the option of buying a more wide-angle lens, but again, you need to learn to work with what you have.

A smaller aperture gives you greater depth-of-field, which means that objects are less blurry. Think like a pinhole camera: an infinitely thin pinhole will give you a perfectly sharp image at all distances, but infinitesimally much light will get in. A big fat pinhole will let more light in, but the picture will be blurry.

All cameras overexpose sometimes and underexpose sometimes. Just learn when it is likely to do either of those, and adjust the exposure accordingly. As for taking every shot six times, many cameras will do that for you automatically: it's called exposure bracketing. They take a shot exposed with the selected settings, another slightly overexposed, and another slightly underexposed. (How many, and how many stops of exposure it sets, can usually be set in the camera.)

FlipC said...

First off I've added an simple and complex entry for DoF on its own. The simple boils down to big number aperture = big depth of field.

As for the LCD screen I agree with Dan, and that's why the focus lock is an important feature. Not only does it allow you reposition the image, but it stops the camera changing any of the settings. So if you focus-lock and it appears dark then that's the shot you'll be taking.

Dan - looking at the manual it appears the S304 only has a centre AF point, if Orphi's just taking the shot as is then it would have been pointed straight at the tree. My only thought on this point is that he's not using the focus-lock option to allow the camera a chance to adjust?

Orphi - Okay colour cast. I mentioned that there's normally one present at all times yet our marvellous brains can filter it out. So why do we get a blue colour cast on some outdoor shots? Look up at that big blue sky and consider why the sea appears blue. The way to get around it is to use a White Balance function.

Unfortunately the S304 doesn't have a manual white balance setting only presets. I guess it's set to Auto, try Daylight (little sun picture), Shade (sun with cloud) or Cool White (centipede with 3). Ah hell try them all and see what they do.

Orphi said...

I can understand the autofocus not working when it's dark. Obviously it needs light to be able to see so it can determine if the image is focused. My problem is it's not dark! It's not even slightly dark. It's really quite bright. But my camera still can't see anything unless it's dazzlingly bright. It just seems absurdly insensitive to light for whatever reason.