First off, I will be 100% honest and let you know I just recently had an ‘ah hah’ moment about how photography works.
This information is based from the perspective of not knowing what to do in any of the advanced modes and mostly relying on auto when it was an important shot. I just recently figured out how the triangle works and why it is important to have manual modes on a DSLR Camera.
Sooooo… this is the boring part, but if you understand the next couple of paragraphs, then you just might have your first ‘ah hah’ moment. We cannot use anything to its full potential unless we know how it works.
DSLR cameras are no where near the quality that our human eye can see, we have to use the absolute latest technology to even come close to the quality our naked eye takes for granted.
All DSLR cameras have an electrical sensor, this sensor is square and thin like a piece of paper, it is about the size of your thumb nail. The cheaper the camera, the smaller this sensor is. This sensor turns light into pixels, the more pixels the better the image. The problem is how these sensors pick up light. Without a lens to ‘focus’ the light, a sensor will pick up a nice huge image of the same color, only producing solid black, grey or white images. The longer the sensor is exposed to light, the more it will produce a blank looking pure white image.
Now lets imagine we put a lens in front of the sensor that focuses light perfectly on the lens, we still have an issue with pure white images because we have no way to stop the light from hitting the sensor. On a bright day, we might want the light to hit the sensor just a fraction of a second because the light overwhelms the sensor, but at night the sensor cannot get enough information to make anything but a black image. So at night, we have to let the light hit the sensor longer so the sensor gathers enough information to make a photo, maybe a whole second or two even.
A sensor is absolutely useless to us with out a way to time how long light hits it. This is what photographers refer to as a shutter, or shutter speed. It is literally a little black cover that opens up for however long you tell it to let light hit the sensor and quickly covers the sensor back up. So it would be fair to say the faster the shutter speed, the more intense light the sensor requires to contruct an image.
So lets say you have experimented enough to know that you need a slower shutter speed when you go into the city at night to take photos of buildings. You will absolutely 100% need a tripod. Why? Because if that little bitty sensor moves around even a tiny bit while it is collecting light information, you will see it in the photo. The buildings will ghost in the direction of movement of the camera. A tripod allows the sensor to sit 100% still to absorb the light evenly across the photo it is creating over the span of 1-2 seconds.
Now lets say you go to a park in the middle of the afternoon to take photos of the family, will you need a tripod? That is right, no, not unless you want to be in the photo and take timed photos. This is because light from the environment is so bright and overwhelming that the little sensor can only handle a fraction of a second of it to make a full blown beautiful photo.
So the little turd of a sensor is not so amazing in terms of versatility, it has needs, and if you don’t fulfill those needs, it wont fulfill your needs. DSLR Cameras are based on early cameras, there are only 3 ways to manipulate the light traveling to the sensor.
Shutter Speed (camera) – ISO (sensor) – Aperture (lens)
Next up, ISO. Why should we care how sensitive the little electronic sensor is?