The basics of photography
Author: Pieter De Pauw
As always, and with almost everything in life, "balancing" and "defining what matters" are important. Same goes for photography...
There are many variables you can control or can master on a camera, but frankly, it comes down to a fundamental trade-off between the exposure time and aperture size (diafragma).
The exposure time defines how long you expose the sensor of your camera to the light: the longer the exposure time, the more light on the sensor; the faster the exposure time, the less light on the sensor. But… longer exposure time requires the camera to be stable and will always leave traces of moving objects.
The aperture size defines the size of the aperture on your lens or camera to allow light to come onto the sensor. The bigger the aperture, the more light on the sensor; the smaller the aperture, the less light on the sensor. But… bigger aperture will come with a very small depth of field. Always remember that a pinhole camera would give you infinite depth of field (meaning all subjects on foreground or background would be a 100% sharp).
Now, here is where the dilemma starts!
As a photographer, you need to decide what you want to do: do you wish to isolate the object from the background or foreground (and thus a small depth of field or big aperture), or do you wish to provide enough context (and thus large depth of field or small aperture)? Do you wish to capture motion, and thus allow for blurry effect, or do you want a 100% sharp image?
Next to this, you have some limiting factors:
- shooting with a hand-held camera will require an exposure time less than 1/focal length. So if you shoot at long focal length (e.g. telephoto or zoom at 300mm), you need a very short exposure time (< 1/300) to avoid vibrations that could affect sharpness of your image
- shooting on a tripod could give you longer exposure times, though might result in a blurry effect in case the object (or part of the object) is moving
- the lens cost and quality: some lenses have bigger f-numbers than others. The f-number defines the minimum aperture size you can use for this lens. This minimum aperture size is required to get sufficient light. Lenses with lower f-numbers (and thus bigger aperture sizes) are faster lenses as they need less light, but also much more expensive
Fast dilemma resolution will require a lot of practice, and knowing your camera as well as all your equipment inside out will help a lot.