Photography - Carousel week 3

SLR cameras

SLR Defined

SLR is an abbreviation: it stands for Single Lens Reflex.

Now you know what SLR stands for but that doesn't really help answer the question, does it? Let's define further:

Digital single lens reflex camera

With an SLR camera, you see exactly what the lens sees

You can change the lens on a digital SLR

Digital SLRs have large image sensors that produce high-quality photos

An SLR has a near-zero lag time, and is ideal for action photography

Bottom line? Digital SLR cameras are versatile.

You can take photos of everything from sleeping kittens to race cars and you'll never be limited by your camera.

With an SLR in your hands you can rest assured that you'll only miss great photo opportunities because you weren't prepared, not because your camera wasn't able to get the shot.

The Anatomy of a Digital SLR

To properly answer "what is a digital SLR?" you have to understand a bit about the mechanics of an SLR camera.

In order to avoid getting overly technical heres a simplified diagram highlighting the key elements.

Light passes through the lens and strikes a mirror (green)
The mirror reflects the light up to a focusing screen
Light passes through the focusing screen and enters a block of glass called a pentaprism (orange)
The pentaprism reflects the image so that you can see it in the viewfinder
When you take a photo, the mirror flips up and a shutter (blue) opens that exposes the digital sensor (red) to light

This is a great example of what-you-see-is-what-you-get. By using the viewfinder you can precisely compose your image and adjust the focus.

Is the image that you see in the viewfinder 100% accurate? In most cases it isn't. If you read digital SLR camera reviews, you may hear a lot about viewfinder "coverage" and "brightness".

Many digital SLR viewfinders only show you 95% of the image that will be captured by the sensor - this is what "coverage" refers to. Unless you are extremely precise when it comes to your photographs you won't notice the 5% difference.

Digital SLR viewfinders also vary in brightness, which is another way of saying how clear the image appears. "Bright" viewfinders make it easier to use manual focus, since you can clearly see the details of your subject.

Shutter speed

Shutter speed, or also known as exposure time, is the duration of the time the film or sensor (depending on the type of camera) is exposed to light. This can make the difference in a photo as it changes the characteristics of the photo. for example it would make the difference if something in the photo becomes blurred like a car traveling at a high speed:

Following this we spent our own time taking photos to show the difference in shutter speeds.

Here are the outcomes of our photos.

Aperture

Aperture is the amount of light which is let into the body of the camera. This can effect the picture by affecting the difference in what is in focus. A low aperture (like F.4.2) would have only one part in focus with the rest of the image blurred and out of focus, just like this image.

But on the other hand, if you was to increase the aperture (like F. 29) this creates the image with everything such and the foreground and background in focus, just like this second image.