Photography basics Learning about exposure
ISO, Shutter Speed and Apertures the photography basics
I’m often asked if we offer photography basics classes or any additional training to support our free Creative Photography for Kids course.
The easiest way for me to achieve that is to write a series of photography basics classes.
Hopefully you’ll find this helpful.
If you are going to learn photography basics then there’s a few simple fundamentals that you need to fully grasp. It’s very easy to put your camera on automatic mode and snap away. If you have an understanding of what your camera is doing then you are on your way to creating better pictures.
Think of the act of photography as nothing more than capturing light. It is the act of capturing light that we call exposure. A correct exposure is achieved by the control of three elements.
The Exposure Triangle
The easiest way think about exposure is to think about what is known as the exposure triangle. The exposure triangle is the three elements that come together to create a well exposed image.
The three elements
ISO – Is the measure of sensitivity that your camera has to light. (ISO stands for International Standards Organization which is based in Switzerland but that’s not important. Even less important is that it used to be called ASA which stands for American Standards Association).
ISO is really a throwback to the days of film. Digital ISO is simply your camera mimicking different film sensitivity.
Aperture – the size of the opening in your lens which lets light into your camera. The size of an aperture is know as an f stop.
Shutter Speed – the amount of time your camera shutter is letting light onto the camera sensor. This is measured in fractions of a second.
If you are using your camera on fully automatic mode then your camera decides for you how these three different elements are going to be changed to create a well exposed image.
Why is that not good?
Your camera is trying to find an average. It’s looking for an ISO which isn’t too high (and grainy), an Aperture with has an average depth of field (area in focus) and a shutter speed which isn’t too slow (and will cause blurred images).
Quite simply your camera is trying to create an average image. But you don’t want an average image do you?
I hope not, and hopefully you will want to be creative. To do that you will need to control your settings and tell your camera what to do and not to do.
Fancy Camera Settings
You might have noticed some of those fancy settings which sound as confusing as they are exciting.
These camera modes include, but are not limited to, Portrait, Scenery, Panorama Shot, Sports, Night Portrait, Night Scenery, Hand Held Night Shot, Food, Baby, Pet, Sunset, High Sensitivity….the list goes on.
There’s no special magic happening inside the camera when you use these settings. All the camera is doing is choosing a bias towards a certain element in the exposure triangle and turning the flash on and off.
Scenery: The camera is using a small aperture which means that the whole scene will be in focus whilst disabling the flash.
Portrait : The camera turns on the flash and chooses a large aperture so that the background will blur.
Once you understand all of these elements, and I hope you will reading these articles, then it is easy for you to not only achieve what your camera is doing in these settings but also do it better.
Photography Basics ISO
One of the three elements of exposure triangle is ISO which stands for International Standards Organization. ISO is the measure of sensitivity that your camera has to light.
In a way this is a bit of a throwback for the film days and to be honest not a completely standardised measurement in terms of quality. It is however fairly standardised in regards to sensitivity.
Back in the film days we used to refer to film as fast or slow. Fast being anything with a high ISO and vice versa. A typical slow film would be something like ISO 100 whereas a fast film would be ISO 800 plus.
Slower film with a low ISO would be used for portraiture or landscape photography as it would have considerable less grain and noise. In fact, the hardcore landscapers would be keen on ISO 50 film but due to the fact that you would need long exposures a tripod was almost always needed.
Fast film was preferred by sports photographers as they could use high shutter speeds as the film was very sensitive to light.
Here in the UK ISO 400 was the preferred consumer film as our grey overcast days need all the help they can get!
In the digital world the sample principles of sensitivity apply and an ISO setting of say ISO 200 is roughly about as sensitive as an ISO 200 film.
The big difference is the type of grain and the digital noise that we see from a digital image. Back in the days of film, grain had a very particular quality to it which was actually quite aesthetically pleasing.
For a long time digital grain has not been a pretty thing. Now we have overcome the need to keep on raising the megapixels in a cameras in order to create an image that does not appear pixelated we can worry about the light sensitivity. I’m not saying the pixel war is completely over but those manufacturers who are concentrating on other things like increasing the dynamic range or low light performance of their cameras will ultimately produce a more desirable product.
The main reason we spend silly money of pro cameras is that they are very sensitive to light (amongst other things). With the latest DSLRs you can photograph in near darkness and still have a great quality image. The main advantage of this is that it gives me more options as a photographer. With good quality high ISO I can photograph without flash and use faster shutter speeds.
Every camera is different. As a rule; new + expensive = good quality high ISO grain. Like everything, you pay for what you get but just because you have certain capabilities doesn’t mean you’ll use or need them.
Photography Basics Experiment time!
To work out how good the quality of ISO is in your camera do a little experiment.
Photograph the same scene (from a tripod if you are inside) on P (programme mode) and only change the ISO setting. Start off at 100 and work your way up.
Use your judgement to what you consider to be an acceptable amount of grain and noise in your image.
Now do the same holding your camera by hand. You’ll probably notice that the first few images are blurry. This would be down to camera shake as your camera settings are being changed to a slow shutter speed……but more about that in a minute.
Photography Basics Shutter Speed
We’ve talked about the Exposure Triangle and the first element of that which was ISO. The next element I’m going to talk about in Shutter Speed.
Simply put, your shutter speed is how long your shutter is open and exposing your camera’s sensor to light.
Back in the very early days of photography the cameras used wet metal plates covered in a similar coating to what eventually became film coating. These wet plates were not very sensitive to light so a long exposures were needed.
Portrait studios were very different in those days, the subject used to have to sit very still in a chair at the very top of the building (often with a skylight) and often had neck-braces to keep them from moving and blurring the image.
Luckily these days we have kick ass sensors which don’t need long exposures. This means we can take images with very fast shutter speeds which freeze action without blurring.
Shutter speed is measured in seconds, actually for the most part, fractions of a second. The bigger the denomination the faster the speed. You’ll probably not want to use a shutter speed lower than 1/60 for hand held photography as it’s likely they’ll be too much camera shake.
Photography Basics Experiment time!
I’m a big fan of experiments so here’s a couple to try.
Find a subject that isn’t moving.
Set your camera up to S (Shutter priority mode)
Take a series of images whilst holding your camera. Start off with a second long exposure and work your way up to something fast like 1/1000.
Once you have downloaded your images then closely examine the images to see how stable your grip is. Remember the setting the has no blurring and try and shoot one step faster for your images in the future. That is unless you have a tripod.
Find an overpass or a viewpoint of a road with steady moving traffic.
Set your camera up to S
Set up your camera on a tripod
Take a series of images. Start off with a second long exposure and work your way up as fast as your camera will let you.
Once you have examined your images it will give you an appreciation for what type of shutter speeds freeze action.
You can try the same experiment with kids in the park (make sure they are your own or that the parents know what you’re up to).
Photography Basics Apertures
In final corner of our exposure triangle is nearly complete! We’ve cover ISO and Shutter Speed now it’s time for Aperture.
Control over Aperture is really where photography goes from meh to AWESOME. The reason is that we can add depth of field to our images. We can make two dimensional images appear to look three dimensional without the need for silly glasses, now that’s magic!
When I first starting learning about apertures at college (many moons ago) it did confuse me a little at first so let me try and keep its explanation as simple as I can.
Aperture = The size of the opening which allows the light into the camera
Doesn’t sound complicated and you’re probably wondering how this can make your images awesome……so let me continue.
When you take a picture your lens aperture opens up to the desired aperture size (that you set) and lets light onto your camera. The larger the aperture the more light is let into the camera.
Your aperture size is measured in f stops. Each f stop is (roughly) twice the size of the last (or half if you go the other way). Typical f stops you might have on your camera – f2.8, f4, f5.6 f8 f11
Hang on a minute……2.8 isn’t half of 4….how does that work?
That’s not important….lets move on.
The bigger the f stop the smaller the hole and the less amount light let in.
Isn’t it just! But try and think about it like this.
Big number = big depth of field
What is depth of field I hear you ask? Well let me explain….
Photography Basics Depth of field
This is where the fun starts (and the awesomeness).
Depth of field is the amount of area in your shot which will be in focus.
Use a big (sorry small) aperture like f22 then lots and lots of your scene will be in focus. This is great for landscape photography but remember that an f stop like f22 isn’t going to be letting much light into your camera so you will have to use either a high ISO or a slow shutter speed (or a tripod).
Use a wide open aperture like f2.8 and then you will have a very shallow depth of field and only a small area (normally where you focused) will be in focus.
This is great for portraits as you can focus the subject and the background will appear blurry. In today’s modern dumbed down culture this has been labelled by some camera manufactures as background defocus. It’s not a special effect or unicorn powered piece of software, it’s just your camera using a wide open aperture. No fairy dust required.
This effect will increase the closer you are to you subject or the type of lens you are using. This is where it does get far too complicated but its worth downloading one of the many DOF phone apps that will guide you through some calculations.
Photography Basics Experiment time!
This one is best done outside in the garden.
Set up your camera on a tripod and set up a model in the middle of the garden about a meter or two from your camera.
Set your camera to A (aperture priority mode)
Start off taking the same photo from the same distance of your subject.
Begin with the largest aperture your lens has (around f2.8 normally) and work your way up to the smallest (around f22)
Examine the results
Do this again but set up your camera just inches away from your subject and once again a couple more meters away.