Beginner's Guide to Photography No.2
Uses of Aperture Priority
Rather than moving on to look at other settings on your camera, I want to continue to look at Aperture priority and how you can use it in a range of situations.
If you carried out the exercises given to you in the first lesson, you should have now got some pretty nice portraits, with a nicely out of focus background.
If you recall we did this by opening the lens right up, as far as it would go (the lowest F number on the dial).
So what if we wanted some of the background in focus or if there were people further away from your camera that would be out of focus using the above technique.
What we do then is to close down the lens, (by dialling a higher number F level on the dial). This increases the depth of field so things or people in the background become in focus.
Using the same principle as above, if you wanted to take a landscape picure, then you would normally want to show as much of the scenery in focus as you can, both foreground as well as objects far away.
To achieve this great depth of field we simply stay on aperture priority but dial in the highest number possible, thus closing down the lens.
A word of Warning!
When you close your lens down to get a big depth of field, the lens will let in a lot less light (remember the exercise we did in the first lesson). This will mean that you have to take he picture at a far lower speed.
If the speed is too slow and you have any movement of the camera, you will get motion blur, especially if you are using a longer lens or are taking objects further away.
There are a couple of ways of dealing with this, the best way is to put your camera on a tripod or onto a solid object, then set your camera to take with a short delay (timer setting of say 2 seconds). This will cut out even the movement of you pressing the shutter.
The other way we will deal with in a later section (it will be titled ISO in case you want to refer to it).
So how do you know if you will get motion blur on your image?
There is a formula. First have a look at the lens of your camera and it should give you either a number in MM (e.g. 35mm) or a range of numbers (e.g. 80-200mm).
If it is a range of numbers you should be either to half press the shutter to see the mm or should be able to look at the top of your camera where there will be a guide as to what millimetres you are taking at (this is in fact the focal length of the lens, but more about that later).
Once you have got this number, set your camera, look through the viewfinder and half press the shutter button. In the series of numbers you will see the shutter speed (eg 200 which means 1/200th of a second).
If the number in millimetres (the focal length) is bigger than the number shown when you half press the button (the time) - you need a tripod!
So if I was using a 50mm lens and it showed I was taking at 1/45th second. I would need a tripod.
A lot of amateur photographers would try to set a fast time for sports photography, setting the camera to T (or Tv).
But in doing this there are too many other factors that could mean you are not getting the best shot. Are you taking too fast for the camera and lens to cope, so the shot is underexposed? Could you take it faster than how you have set the camera so that it is even sharper?
The way round this is to go back to our old friend Aperture mode.
What you then should do is to open your lens as wide as possible (the lowest F stop possible). This will mean that your camera will automatically adjust the shutter speed to the fastest possible speed it can and will correctly expose the shot.
A Quick tip
In ball sports, if you are taking a picture of a free kick or a strike of the ball, it is often more aesthetically pleasing to take a picture immediately before someone strikes the ball rather than after.
Two further points about using a narrow depth of field with your lens wide open:
The effect is more pronounced the nearer you are to the subject.
and is more pronounced on lenses with a longer focal length (so it would be more pronounced when you zoom in on a subject)
Conclusion and Exercises
Really, as a professional photographer, I find that controlling the aperture of the lens and taking pictures in aperture priority is the most important way of controlling how your photographs look, even when I am taking pictures in fully manual mode, I still find that I am more aware of the aperture mode than any other setting.
Try now practising changing the lens from open to closed (low F stop number to large) on a range of subjects. Compare the results to what you have learnt and how you would apply this in the future.
Try doing this on;
A garden object (with the garden behind)
Enjoy using your new found skills and I hope to see you in Section 3.
© 2017 Dave Proctor