Digital SLR cameras are quite simple. It may be hard to believe, but it’s true! Let's compare operating a digital SLR to using your television set. Nowadays, televisions come with a large variety of options such as memory scan, picture in picture, color correction, sound options. Do you have to use all of these features to watch TV? Not at all. In fact, you only need to know three things to watch TV:
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Here's the thing: with a digital SLR camera, you also only need to know three things:
- How to turn it on
- How to change the aperture
- How to change the shutter speed
And that’s really about it!
Okay, so maybe you don't even have to know that much, since many people use their digital SLRs without ever changing aperture or shutter speed anyway. It's easy to use a digital SLR camera in ‘auto” or “program” mode but this defeats the purpose of owning an SLR camera.
One of the benefits of an SLR over a compact point-and-shoot is that you have control over every photo you take which means you make the decision about how every photo is going to look, not the camera.
Why is this important?
It’s because your digital SLR is in actuality just a small computer. While it excels at processing millions of colored dots of information, it makes pretty poor judgment calls about the artistic qualities of your photos. So once you wrestle control of aperture and shutter speed away from the camera and make them your own, you will see a big improvement in all of the photos you take.
Here's the simple definition of aperture:
Aperture is the width of the opening in your camera's lens.
A camera lens works a lot like the pupils of your eyes. When you're outside in bright sunlight, your pupils are very small to limit the amount of light entering your eyes.
If you wake up in the middle of the night, your pupils are wide open, helping you to see in the dark by letting more light in.
Let's say you were to measure the diameter of your pupils during the daytime. They would have an aperture of 32. If you were to measure it in the middle of the night, your eyes might have an aperture of 2.8.
This brings us to what is probably the most confusing concept about aperture numbers. They are the opposite of what you would expect.
It’s basically like this:
The smaller the aperture number is, the wider the aperture will be.
That there is probably the most important thing you would need to know about aperture and once you understand it, everything that follows will fall into place.
To remember this, I think of aperture numbers as fractions instead of whole numbers. For example, if I asked you if 1/4 was larger than 1/2, what would your answer be? If you think about it this way, it makes sense that an aperture of 8 (1/8) is smaller than an aperture of 4 (1/4).
Just like time (measured in seconds and minutes) and distance (measured in feet or meters), apertures are measured in f-stops. This is why aperture numbers start with the letter f, like this: f/2.8.
There is a common scale for apertures:
The chart also basically reiterates what I said before. An aperture of f/2.8 is wide (letting in a ton of light) and an aperture of f/22 narrow (letting in a tiny amount of light).
When a camera lens is set to a narrow aperture it is also called "stopped-down" and when it's set to a wide aperture it's called "wide-open". Each full f-stop change either doubles or halves the amount of light that passes through the lens and lands on the camera sensor as seen in the following chart.
I should also add that if you're changing the aperture on your SLR camera, you'll probably see that the camera is using more than just the standard set of f-stop numbers. This is because your camera is set to use half-stop or third-stop increments. When your camera is set to use half-stops or third-stops, it just gives you more aperture numbers to play around with. It does not change the relationship between the standard set of f-stops.
Here's the half-stop scale with the standard stops in bold:
And here is the scale containing both half and third-stops:
Well, there we have it. As I mentioned before this is probably the most complicated part about aperture. The next topic will be very simple compared to this one as I will be getting into aperture
priority.
Aperture priority is a mode that is available on all digital SLR cameras.
Your SLR will have a dial on the top of it with some program modes such as landscape, portrait and night. The dial will also have letters on it like "P", "A", "S", and "M". Aperture priority mode is the "A" setting on your camera which could also appear as "Av".
In aperture priority mode you manually change the aperture, while the camera selects a matching shutter speed to ensure a good exposure.
Every photo you take is a relationship between aperture and shutter speed (I'll go into more detail another time). When you change the aperture, the shutter speed must also change to compensate.
In aperture priority mode, you only have to worry about one variable, aperture, and the camera does the rest. This mode is kind of like a baby step feature because it lets you begin to experiment with using the manual settings on your camera without jumping into the deep end of the pool.
This pretty much sums up everything on aperture and its effects on the amount of light it can let through. Next, I will be covering its effects on the lens' depth of field. Until next time if you have any questions, please ask.
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