the fStop - Image Exposure
When you are taking pictures [using either a film or a digital camera, the image gets captured based on light coming through the opening when you press the button (the shutter release). There are 2 things that determine how much light gets through the opening. The first is the size of the hole (the aperture).
For years, I wondered what the numbers on my camera lens meant. In the front of your cameras lens there is a set of numbers that look something like 1:3.8. These numbers tell you that the maximum size of the hole is f3.8, the smaller the number the larger the hole. You might be asking right about now, what's the 'best'? The best is 1:1, but for all but a few pros, you'll never need a f1.0 opening.
The other day, I did a little experiment with my Nikon 995 camera and took the 10 pictures below. I set my camera to a 1/125 second shutter speed and changed the aperture on my camera from the biggest opening to the smallest opening [the camera was fully manual]. As you can see, the larger opening (as indicated by the smaller f#.#) the brighter the image, this is due to more light coming into the camera hitting the sensor.
- All of the exposures above can be considered 'correct', depending on what you want to accomplish.
- When working with zoom lenses, the largest possible aperture size gets smaller. This means that to allow the same amount of light to hit the sensor, you need to keep the shutter open longer. Most cameras will do this automatically for you, it just means that you'll need to keep the camera steadier to get a good picture. For more information on shutter speed, click here.
- All photos were taken with the camera hand-held, not on a tripod so please forgive any camera shake.