Tuesday, March 1, 2011

Tutorial Tuesday: The DSLR; a (very brief) history

Hey guys! Welcome to my first EVER Tutorial Tuesday!

Today I am going to (very briefly) talk about what a DSLR camera is and (briefly) explain how it works

     The first ever known photograph was developed in 1826 using a pewter plate covered in a petroleum derivative which hardened when exposed to light. Then a whole lot of time passed and now we have the fabulous DSLR camera!

How does this amazing contraption work? It's basically a small and VERY powerful computer, thinking about it that way kind of helps when explaning it. Each DSLR has the same basic components:

1) The Lens: It might help here to explain that D-SLR stands for Digital Single Lens Reflex. This means that each camera is made up of a "body" (the bulk of the camerea, containing the shutter and the image sensor) and a seperate and interchangable lens (the front of the camera, the glass through which we see an image containing the aperature). Many professional photographers refer to their lenses as "glass." There are about as many lenses as there are subjects to take pictures of. Prime Lenses offer a fixed field of view and Telephoto Lenses offer a range of fields allowing you to zoom in and out depending on what you want to focus on in your image.

There is plenty to talk about lenses but i'm getting ahead of myself. Just remember for now that the lens is the window to your image, it can be interchanged in a DSLR and it contains the aperature.

2) The shutter: The shutter, contained within the camera body is actually a set of two sliding panels which move to expose light to the sensor chip. The first panel moves to start the exposure and the second panel moves after a designated amount of time (usually a fraction of a second) to cover the sensor chip and end the exposure.

3) Sensor chip: The "film" of a DSLR camera. Exposed to light by the shutter it converts thousands of levels of data from the scene and converts it into a digital image found commonly on the LCD screen on the back of the camera body. When you change the ISO settings in your camera you amplify the signal volume of the data coming from the chip and in essence making your sensor "more sensitive to light." Even though this isn't what actually happens it helps to think about that when you think about how your sensor chip relates to ISO.   

4) Mirror and Pentaprism: This is what makes a DSLR a DSLR. In order for you to be able to look through the lens of a DSLR camera there are two main mirrors inside the camera body that reflect the image captured by the camera. You can actually see the main mirror when you take the lens of the camera.

Sony Alpha DSLR; showing mirror
 The second reflective medium is the pentaprism which is what actually allows you to see the image correctly. The first mirror (pictured above) flips the image upside-down (think old school pin hole cameras) and the pentaprism using several angled sides to flip the image up correctly.

Here is a nice image which sums up everything I have just discussed. You can see the light traveling through the aperature in the lens, bouncing up through the mirror and through the pentaprism into the viewfinder that you look through. When you are ready to made the exposure the mirror moves away and the shutter does it's thing to reveal the senor chip. Pretty amazing isn't it?

That's about it in a nutshell folks, a pretty narly piece of technology that we can use to strech our photographic skills to hights never before imagined. Just always remember that even though this little machine is very intellignet, it has absolutely no idea what it is looking at. It doesn't know if it is seeing a candle lit room or a stadium filled with floodlights. It is up to US, the PHOTOGRAPHERS to accurately judge what WE want to take an image of and show the camera how to record it the way we see it. DSLR camers are a very powerful tool, but that's it. We are the painters and the camera is our brushes and canvas.

So that's it guys, my first EVER Tutorial Tuesday! Hope you guys learned something new and I can't wait until next week! Please forgive some of my technical jargon I know some of you are thinking ISO? WTF? No worries, it will all be explained in due time!

If you have any questions please leave me a comment!

See you on the other side of the lens!

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