In last week’s lesson we took a look at the main features to look out for when buying a new camera. The features we went into in that lesson should have helped you narrow down your choice to a few cameras, but now that you have to make your final choice you should look through the finer specifications to choose.
This is where you actually need to start paying some serious attention to detail. Some cameras might tick all the right boxes, however there might be something that you cannot live without that is missing – and you don’t want to find this out after you’ve parted with your hard earned cash.
Article after the break:
Ergonomics & Size
A mirrorless interchangeable lens camera compared to a large DSLR.
Choosing a camera has never been harder. There were times when different types of cameras lived in completely different price points and you effectively bought the best camera possible within your budget, possibly after having decided on which brand you prefer. This still works well in two categories nowadays: the very cheap point-and-shoot range built by nearly ever manufacturer and the high end DSLRs. If I’m after a $3,000 body, there isn’t much choice. A handful of manufacturers build them and my selection will probably be based on what I’m upgrading from because I’d want to keep using my lenses.
If you have a budget of $/€ 500 – 700, however, there has never been a better (or worse) time to be looking for a new camera. You can get yourself a high-end compact camera; a low end DSLR; or one of the many mirror-less interchangeable lens cameras available on the market. All will set you back approximately the same amount of money and all will offer a distinct set of advantages and disadvantages, so you have to be very careful when choosing.
In this lesson I aim to start going through some of the different aspects that will go into the choice and explain them in relation to day-to-day photography, not numbers in a column.
Form Factor
This is something most people seem to underestimate, but it will impact your usage of the camera greatly. For a camera to be good it must not only take pictures at the quality you expect from it, but it should be of a size that you are comfortable with.
It is no use having the best camera in the world if you are not prepared to carry it around with you, but then again if you are not used to shooting off a screen you need a camera which is large enough to house a viewfinder. The variables are endless, and my advice would be to actually make the trip to a physical shop to try the different options out. Check the weight, check whether it fits in the pocket of your favourite jacket and shoot a few pictures to see whether it feels natural.
The kind of photography you are into will also impact your choice of camera form factor. DSLRs are probably better equipped for fashion photography or landscapes in general, but they are not too practical for street photography, where something far more discreet would be an advantage.
Sensor Size & Image Quality
MEGAPIXELS! Camera builders shout out about them as if they were street hawkers selling fish at the market, especially with the smaller consumer cameras. They make you think that the more you have, the better. While this is not exactly a lie, there is much more to image quality than pixel count.
A camera records images on a sensor which is light-sensitive. This sensor is made of a whole lot of little “mini-sensors” which individually record a dot of colour. Put these dots next to each other and you get a picture. Pixel count tells you how many dots a camera is capable of producing per image, but it does not tell you the quality of the data that it is recording or the size of the pixel.
Different cameras have different sensor sizes:
Most compact camera sensors would fit in the smallest size shown in the image above (or even smaller). Cameras with exchangeable lenses like hybrids and most popular DSLRs would have sensor sizes around the APS-C size. Professional DSLRs are usually what we refer to as “full-frame” or 35mm.
A larger sensor for the same pixel count gives you larger pixels. While this will not translate into a larger image on screen or in print, it will result in better image quality for various reasons, including:
A larger pixel will absorb more light in the same time-frame, therefore giving you much better low-light performance with lower noise. This is the reason why cameras with larger sensors can usually perform better at higher ISOs
A larger pixel will have less spillage from the pixel next to it, and as a result give you better definition and less digital noise
Knowing all this is helpful, especially as background, however there is only one way to be sure that you are buying a top-notch sensor. Use the Internet to research the cameras you are eying up. There are quite a few sites that offer in-depth reviews of cameras and most of them dive quite deeply into image quality.
Now that you’ve chosen a camera with a sensor that will record your images accurately you need to start taking a look at the glass that will bend the light faithfully into your little black box.
There are thousands of lenses out there, each one of them with a specific use and audience in mind. You don’t need a camera that can take them all but you have to make sure that the camera you’re buying will satisfy your most basic lens-needs.
If you are considering a prosumer (advanced) compact camera then you should take a long hard look at the lens the camera is built with because it will be there for life. You cannot change lenses so you must be sure that it fits the bill for all your planned uses. Is it wide enough for your family group-photos and will it zoom in far enough? If you want low-light photography then you need to search for one of the few consumer cameras with a wide aperture (f2.8 or f2.0).
With all other systems with interchangeable lenses you have to take a look at the lenses that are available for your needs in particular. Long term you can spend more on lenses and other accessories than you spend on the camera body itself, so thinking about your future needs is key. If you are into portrait photography, what prime lenses of around 130mm are available for the system you’re considering? If it is wildlife shots you’re after, on the other hand, then you should start off your deciding process by finding the best 400+mm lens around.
Others
In next week’s lesson we’ll take a look at more factors you should look out for when choosing your next camera.
Photography for Ignorant Geniuses is a set of tutorials I give out on a weekly basis about the science behind photography. For more information (and to subscribe) click here.
By understanding shutter speed you can learn how to take photos that show motion.
In the greater scheme of things, shutter speed is probably one of the easier concepts to understand in photography. It affects the feeling of movement within an image.
At the most basic level you only need to understand one simple concept:
If the shutter speed is short (fast) enough, any movement happening in the photo or behind the camera will be frozen.
Keeping this in mind you should quickly realise there are two major areas in which this will impact our photography: involuntary camera shake that will ruin photos; and choosing between showing movement or freezing action. Work with a shutter speed which is fast enough and all your photos will be razor-sharp (as long as you get the focus right).
Shutter Speed & Camera Shake
Camera shake is the ugly head of shutter speed – something that we usually do our very best to avoid. If shooting on automatic and we have our flash turned off, sometimes the camera will choose a shutter speed which is very low (if shooting inside, or at night, for example). Some point-and-shoot cameras will let you know that you are likely to have shaky pictures – but that doesn’t really help.
Horrible camera shake - the photo on top was taken at 1/400s, the one at the bottom at 1/6s with no Image Stabilisation. Both pictures shot at 55mm.
Camera shake also increases as we zoom in because all our movements are amplified and therefore greatly exaggerated. This means that a shutter speed that might not result in a shaky picture when shooting at 28mm (wide) will be shaky at 280mm (telephoto) because each little shake in our hands will be multiplied tenfold!
As a rule of thumb, given average conditions and relatively steady hands, it is safe to assume that for a good, clear, shot you need to have a shutter speed which the same fraction of a second as the length you are shooting at. It might sound complex, but it is actually very simple:
If shooting at 30mm you need to assume that you need a shutter speed of at least 1/30 of a second for a shake free photo. At 300mm you need 1/300 of a second for a sharp picture and so on…
When you are shooting in a situation which might result in camera camera shake, there are a few things you can do to avoid it:
Increase ISO and/or Aperture
The best way to increase shutter speed is to open your aperture as much as possible. Select the smallest f-number available on your camera. Once you have done this, if it is not enough you will have to resort to your camera’s ISO. Push it up slowly until you are shooting within the safety range suggested above. Keep the usual ISO caveat in mind – each time you push it up a notch you are reducing the overall image quality by adding noise to the image.
Steady yourself and Grip the Camera Well
You should always hold your camera with both hands, but when shooting in challenging conditions this becomes far more important. If standing upright make sure to open your legs slightly and put one leg in front of the other to give you maximum stability. I sometimes find a wall to rest against to help me steady out too.
Kneeling down and holding the camera well allowed me to take a sharp shot in this fashion shoot we shot at dusk.
Add Stability
A tripod is the best way to avoid camera shake – whether you’re shooting in the dark or using a telephoto lens in challenging light, nothing beats a sturdy tripod. If you don’t have one handy, however, you will need to get creative. Support your camera on anything you find at hand – a glass if you’re at table, a pillar or a barrier – I’ve used everything imaginable to get a steady shot when shooting in the street.
Invest in Image Stabilized Lenses/ Cameras
If you are in the process of buying a new camera or lens for your interchangeable lens system, you should really consider image stablilzation (IS). There are various methods of stabilizing images and most of them work very well.
Stablilization comes in various levels usually ranging from three-stop to five-stop. Keep in mind that IS only stabilizes camera shake – it will not hold your kid still in a photo, you need a different kind of stablilzation for that!
Shutter Speed & Motion
I will eventually develop this into a lesson in itself, however once you have understood the concept of shutter speed enough to avoid shaky pictures, you can start playing around with the values to use them to your advantage. There are many types of photography that need shutter speed control, however the most obvious two are covered below:
Frozen action
If you shoot action photos at a fast enough shutter speed you can freeze motion. When you freeze motion you need to make sure that the image itself conveys action. So for example if you’re shooting a sprinter, or the motorcyclist in the image below, it is more important to freeze motion because the image in itself already implies action.
Shot at 1/1000s, this image freezes the moment completely. The position of the motorcyclist, however, does not leave much to the imagination about whether there is action in this shot!
Panning to show motion
On the other hand, there are times when you want to show motion by panning along with the subject. By panning at the same speed of the subject you are shooting you can ensure that the subject itself is sharp but the background is blurred. When shooting this way you should always set your camera to drive mode (or multiple shots) and keep your finger on the shutter release. This will eat up your memory but it is really the only way to ensure that you get at least one good picture out of each passing by.
When you want this kind of photo you need to take much longer exposures, because the goal here is to actually show motion.
In this shot the car was driving by and I was panning at a speed that matched it. By shooting at 1/80s I blurred the background and foreground enough to show that it was driving by at speed while keeping the car and driver sharp.
Photography for Ignorant Geniuses is a set of tutorials I give out on a weekly basis about the science behind photography. For more information (and to subscribe) click here.
Most amateur photographers look at photos taken by people with slightly more knowledge in the subject and try to understand how their backgrounds look blurry, therefore making the subject stand out much more. In this lesson we shall go into the reason the background (or foreground) is blurry and we shall explore the factors that will help you achieve perfect pictures.
The first, and probably most obvious, query is usually to understand what makes the background blurry. That, in itself, is easy enough to answer. The background looks blurry because it is out of focus. The technique used here is sometimes referred to as selective focus – because you specifically select which part of the image you would like to appear in focus.
If left to their own devices, however, most cameras will try and set themselves to avoid a setting which will aid in this for one simple reason: selective focus is a very dangerous game to play. The more you push your camera to achieve a shallow depth of field, the harder you are making it for you to focus well – we shall soon see why.
Focal point and the plane of critical focus
The laws of the physics of light dictate that every optical device has one specific focal point. That, my friends, is that. It is not up for debate (well, surely not by me). The lens in your camera is an optical device and it therefore has one focal point too.
A focal point is simply the one spot at which an object shot through a lens is perfectly in focus. This is what a camera is determining when moving the lens in and out when set on autofocus. Once it has selected the right spot and moves the lenses within it to be at the right distance from each other a camera produces a shot which is in focus and therefore has a sharp subject.
Modern cameras usually choose the object to put in focus based on their analysis of the scene, so if you have a face in the picture they will usually try to focus on it. SLRs have a set of focus points and most of them allow you to either select one particular point to focus on or else set the camera on auto, and it will attempt to choose the right point for you. Sometimes, with an SLR you can also choose to first focus on a certain spot by pressing the shutter half way down and then re-compose the shot before actually clicking all the way down to take the shot. This allows you to have a focus spot which is not on one of the points the camera comes pre-defined with.
Thankfully the one spot that the camera has focussed on is not the only part of the image that is in focus. Imagine seeing a scene from the side. The plane of critical focus would be the flat surface created if you had to slice it at the focal spot. You can safely assume that this is completely sharp too.
Depth of Field
Thankfully most camera lenses are slightly forgiving and together with the plane of critical focus you also get some leeway for sharpness to either side of the focal plane. This area in which objects appear sharp is defined as depth of field.
In the diagram below we can see that the focal spot is surrounded by a short distance to either side of the subject in which the rays of light are still close enough to the focal spot to fool our eyes into thinking that they are in focus. Once an object is outside that space it will appear to be out of focus:
The comparison below shows the same subjects at different depths of field:
Controlling Depth of Field
By now you should have guessed where this lesson is going. For complete creative control over your photos you need to know how to choose the amount of depth of field you want. To do this you will need to understand what influences depth of field, and ideally why.
There are three major factors that affect the amount of depth of field in a photo.
Aperture
As you might have realised from the example I showed earlier on, I changed the aperture from one picture to the other to show you how depth of field affects a photo. In the diagram below we can see the same object being shot at different apertures. By closing the aperture in the second example we have made the depth of field significantly longer.
Remember: Larger number denotes smaller aperture!
Distance of the object from the lens
Applying the same rules of physics shows quite clearly why moving an object further away from the camera will give us a longer depth of field. Light has to be bent less and therefore you have an acceptable focal area which is wider.
Focal length of the lens
For a lens to be at the same aperture value at different focal lengths it needs to be physically open much wider. This means that at 18mm at f2.8 a lens has to be open much less than it is would need to be open at 55mm at f2.8. This is why telephoto lenses with wide apertures are so bulky!
Focusing at infinity
The rules of depth of field change slightly when you focus at infinity. When the object you are shooting is beyond a certain distance (about 10 meters) and at the end of the focusing range of a lens, the only objects in the picture that shall be out of focus are the ones that are closest to the camera. The rest is considered to all be in focus.
How to use Depth of Field Creatively
Once you have understood how to control depth of field it is high time you put it into good use.
There are times when you need a shallow depth of field to create effect. Portraits are a perfect example, because a shallow depth of field will allow you to isolate the subject. A close up of an object, such as the thorn below, is also a good time to isolate your subject.
Shot at f2.8 for the shortest depth of field available on my lens.
If shooting a landscape, however, you’d want to maximise depth of field to capture as much detail as possible.
For this landscape photo of Monaco I used a smaller aperture (f7.1) to ensure sharpness throughout the image.
Equipment Caveat Alert!
There is also a fourth factor which affects depth of field, however you don’t have much control over it. This is the size of the sensor. The smaller the sensor you use, the more difficult it is to achieve a shallow depth of field. This means that on a micro-sensor (such as the one in your phone), it is nearly impossible to control depth of field. Most compact cameras also have relatively small sensors, which means that the knowledge you’ve learned from lesson will be very hard to implement unless you have a camera which is geared towards the serious enthusiast or professional.
Most cameras in phones are nearly always in focus because they are built to focus at infinity from a very short distance – around 30cm.
Photography for Ignorant Geniuses is a set of tutorials I give out on a weekly basis about the science behind photography. For more information (and to subscribe) click here.
Photo by Keith Williamson / Licensed under Creative Commons 2.0
At the very basic level, a lens is what controls and directs light onto the camera’s sensor. Lenses are usually named and defined by their focal length in millimeters. Focal length affects two major aspects of photography: magnification and composition (through field of view). Do not worry if you’re lost – the aim of this lesson is to explain how these will affect your pictures.
Exposure is the one of the elemental theories of photography. Even though it is quite a complex subject, it is all perfectly logical. By the end of this first Photography for Ignorant Geniuses lesson you should be able to grasp the theory behind it.
Let’s start by looking at the basics of how a photo is taken. The principle of a camera has remained the same for centuries – we have a lens, a shutter and a sensor (or film, the concept remains the same).
The sensor records the light that lands on it through the lens, while the shutter keeps the light out. So when we press the shutter release to take a photo, it opens the shutter at a set diameter for a set period of time to allow the sensor to capture the image.
Exposure is the quantity of light we need to arrive at the photo we set out to take. An over-exposed photo has too much light and will contain areas which are washed out (white). An under-exposed photo is the exact opposite – too dark, usually with areas that are completely black.
Sometimes you might want to under-expose or (rarely) over-expose a photo for effect though. You wouldn’t do it with snap-shots of your children playing in the park, but a night shot can still look good if under-exposed in areas (as long as the subject of your photo is well-exposed).
An under-exposed vs a well-exposed photo
Cameras do help you out with achieving the right exposure, and every new generation of cameras brings about improvements to the technology used to select the best settings possible for the situation. Nevertheless, knowing what goes on behind the scenes will help you greatly for two main reasons:
The ideal exposure for a camera’s “brain” is usually an evenly well-lit photo, but you might be after something which doesn’t fit the parameters the camera deems right – a silhouette is a classic example.
You need more control over a camera’s settings in order to take good photos in every situation.
This photo is terribly under-exposed for a camera. It would never have taken it on an automatic setting, but it is exactly the effect I was after.
To understand exposure better, imagine that you have a glass you need to fill from a faucet. You must fill the glass up right to the brim, but ideally not splash any water on the surrounding areas. The size of the glass might vary – just like the correct exposure of the photo you need will change from situation to situation – but your goal is always the same: filling the glass to the brim without splashing.
The three factors (settings) that will determine a photo’s exposure are similar to the three variables you have in your average water system:
Aperture – This is the equivalent of how wide you open the faucet.
Shutter speed – Yes, you guessed it – this is the time you leave the faucet running.
ISO – Slightly more complicated to explain, but I like to compare this to adding a pressure pump to your water system. It will allow you to open the faucet for a shorter span, but there is a caveat – the more pressure you add to the water the more you risk splashing all over the place.
To get to the right exposure you can usually use a combination of values, the trick is finding the right one for the setting you are after.
Going back to the glass analogy can help us understand how these three work together:
I need to fill a beaker with water. Let us imagine that if I open the faucet completely it will take 5 seconds to fill. That means that if I opened it half way I would need to leave it open for 10 seconds. The result is the same, the glass is now full. If I turn the pressure pump on at 200% and leave the faucet half open, however, I can still bring my time back to 5 seconds – this is the equivalent of going from ISO 100 to 200.
ISO
Out of all the three settings, ISO seems to be the one that confuses people most. I personally think it is definitely the most simple to understand. I will go into the nuances of aperture and shutter speed at a later stage, but to understand ISO I will just give one thing away. If you use a shutter speed which is too slow you risk ruining a shot because of camera shake.
ISO simply increases the sensor’s sensitivity artificially to help you take photos with less light. That is the only difference it makes on a photo, and there is only one caveat – the higher you pump up the ISO, the “grainier” your photos get. This happens because the camera pushes itself electronically to improve light, sacrificing quality in the process.
A crop of two photos, one taken at ISO 100 (top) and another at ISO 1600.
So the only lesson you need to know about ISO is that you should keep it as low as possible when you have enough light, and push it up as needed when you are in darker situations. Not all cameras perform the same under higher ISOs, in general the more you pay the higher you can afford to push it.
Remember: It is always better to have a noisy photo than not to have one at all, so don’t ignore a good opportunity just because you might compromise some of the quality.
Course-work
Exposure
It will take me a few more lessons to go into how aperture and shutter speed affect the aesthetics of your photos, but until next week try to set some time to browse your photos.
If you use a program like Picasa (which can be downloaded for free here) you can see a box with the basic settings (including the aperture, shutter speed and ISO) at which the photo was shot.
Look out for different exposures in photos you took – are some of your photos under- or over-exposed? Was your camera pushing ISO up too much, or not enough?
You can also take it a step further and browse photos on Flickr.com. Most of them give the settings they were shot at if you click on “Actions -> EXIF info”.
ISO
If you have some spare time, look for the ISO feature on your camera. Shoot some photos around dusk on a setting that allows you to override the ISO setting. Start at the lowest ISO and shoot the same scene over and over again, going up a notch at a time up till the very top of the range available.
Once done, sit at a computer, view the pictures at full magnification (100%) and get a feeling of how bad “noise” in the photos gets as you increase ISO. Take note of the point at which photos are no longer acceptable and keep it in mind for the future.
Photography for Ignorant Geniuses is a set of tutorials I give out on a weekly basis about the science behind photography. For more information (and to subscribe) click here.
