How to start photographing with a single-lens reflex (SLR) camera
You can either shoot with an SLR that costs 10 – 100 thousand crowns, set to automatic mode or learn something about adjusting exposure. I don’t want to carry coals to Newcastle, because you can read how to turn on the device in the user manual of every camera. Nevertheless, I am going to explain some important SLR aspects.
Aperture, focal point, time and ISO
Together they create exposition, simply the way how the photo will look. If it is bright, dark; if it has image noise, how sharp the background (even foreground) is. All this together create the final photography. I am going to describe every term in detail, but only on a level you can use practically. So don’t expect any charts and difficult formulas.
What is aperture
Let’s begin with a lens. Light goes through the lens, and when it comes from a strong source, for example sun or flash, we need to reduce it somehow. So we don’t have a plain white area in the photo. The higher aperture number (f number) we set, the more we close down the aperture. See the image below.
What is affected by aperture:
1) Depth of field
The more we open up the aperture (lower aperture number is set), the more blurred the area behind and in front of the object will be.
Example:
If you set the aperture to f1.8, the eye of the portrait is sharp and ear is blurred. If you set the aperture
to f22, the face is sharp and the background scene as well.
2) Exposure
As I have mentioned, if we set higher aperture number, less light ends up on the sensor
or film. If we don’t overdo it, the photo will come up nicely. If we overdo it, some areas will merge together
in black color, and if it’s not an artistic purpose, it’s quite undesirable.
Opening up the aperture works almost the same. We can have an overexposed photography
with white areas and details fading out.
Focal lenght
We are still talking about lenses, concretely about focal point. It’s actually the viewing angle which is transferred through the lens to the sensor.
Example:
Let’s say we have a basic set lens 18 – 105mm. A lens set to 18mm will create a wide view. On the other
hand, if we set the lens to 105mm, the view narrows and the scene is zoomed in. I promised, I wouldn’t
carry coals to Newcastle, but this information might be quite useful for some beginners.
Focal length and depth of field
This is more frequent topic. Here is the rule – the less we zoom in, the larger area is sharp. But if we use a telephoto lens with a long focal length, it can result in a sharp area which is only 1cm wide.
Lens speed
Even though there are already lenses which pass light equally in the whole zoom range, most lenses pass
less light if longer focal length is set.
Reaciptulation
If I want deep depth of field, a short focal length and high aperture is better (e.g.
18mm and f18).
If I want shallow depth of field, a long focal length and low aperture is better (e.g.
105mm and f1.8).
Time
Well, we have covered lenses and now we are getting inside of the the camera body, to the shutter.
When the light passes through the lens as we want, it lands on the reflex mirror which reflects the light
upwards to the viewfinder. When we press the trigger, the mirror moves out of the light path, and the light
shines directly onto the sensor for as long as we set the time.
Expmple:
If we set the time to 1/20s, the photo in motion will be blurred. On the other hand, if we set the time to 1/1000s, the motion will be perfectly frozen. When we change the shutter time, we have to change exposure too. The shorter shutter speed, the less light will land on the sensor, thus the photo will be dark. Also, if we don’t have enough light, we can extend the shutter speed up to 30s and we will have a beautiful photo even in low light conditions. We have to make sure the camera is steady. Even the lightest vibration will cause a blurry photo.
ISO
Light sensitivity. Defines how sensitive is the sensor to the light that comes through
the lens. We always try having the ISO number as low as possible, high ISO values cause
image noise.
I recommend setting higher ISO number when you are not able to brighten the photo by opening up the aperture
or setting longer shutter speed. With a studio flash head, ISO number can be ideally 100
– 200; when photographing in the sun, ISO number ideally 200 – 300;
in a common daylight, ISO number ideally 400 – 200 based on intensity.
It’s only up to you
It’s time to learn what happens, when you change this and that control to
a certain value. What happens, when you take a photo from a different angle with a certain light or a
different type of light, and so on.
The only thing you can learn is to work with the camera. The rest is up to you, the feeling
you have when you see something, when you photograph something and when you edit something.
The photo below was taken with Nikon Nikon AF-S NIKKOR 24 - 70mm f/2,8 ED - aperture
f/2,8; time 1/125; ISO 100; focal lenght 70 mm