Main topics to master in Photography (part one)
Since my last article I have been thinking about the subject of this article. And to be honest: at this very moment of writing it I'm still not sure.
In photography there are a few major topics. If you master these your creativity can be set free. For me the two major topics are:
- Light
- Depth of Field
If you master these two you can do amazing photography!
From this point I decide to introduce you to DOF, Depth Of Field.
Before talking about DOF it is important to know what sharpness is. In optics the limit of tolerable error is usually set at 0.05 mm (0.002 in) diameter for 35mm film/sensor (Source: wikipedia, http://en.wikipedia.org/wiki/Depth_of_field). In plain English this means that the human eye has a certain tolerance to unsharpness. If you take a picture of an object you'll notice that objects at a certain distance from that object are not sharp. There seems to be an area wherein all objects are sharp. Outside that area object tend to blur or be definitely unsharp.
The area wherein objects are sharp (to the human eye) is called the Depth Of Field.
In the figure below you see a (schema of) a camera and a subject.
The camera exists of a sensor or film back and a lens. The subject is a cube.
We focus the camera on the red dot on the cube; the red line marks the area in which all objects will be sharp. So, every object between the red line and the dot will be sharp.
The height of this red line is what matters, this height symbolises the limit of tolerable error as stated above.
In the next image you see what happens if we put the lens closer to the subject (and leave the back where it was). As you can see the red line moves towards the red dot. The area wherein all objects are sharp became smaller.
We say: The DOF became smaller
Or: there is a shallow DOF
This image illustrates what happens if you use a large telephoto or zoom lens.
But what if you don't have a telephoto or zoom?
There are two ways to zoom:
1. Put a telephoto or zoom lens on your camera
2. Move closer!
Figure 3 shows the situation when you zoom in with your feet. Amazing isn't it? The DOF is the same as in Figure 2!
Okay, we know now how to decrease the DOF. What about increasing it?
Well, of course you can do the opposite of the things mentioned above:
- Move your lens closer to the back
- Walk away from the subject
But there's another way:
Make the lens smaller!
In the last figure everything is the same as in the first one. The only thing that's different is the diameter of the lens. A smaller lens will get less light. Because of that the DOF will increase. You can simulate this with your eyes by closing them just a little. You'll notice focusing becomes easier. That's because of the larger DOF!
How do you decrease the diameter of your lens?
That's an easy one: close the aperture!
The smaller the aperture the larger the DOF!
This part one of the article has a lot to do with part two: the Light Triangle. Part two will be all about getting out of the P-mode and getting creative! So: stay tuned!
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For now: Have a good one and use the light to write!
Click here for part two!