Grab your cameras! Let’s talk about exposure
As an admirer of all things pretty, needless to say I love photography – as much contemplating beautiful photos, as the act of snapping them. I carry my Canon DSLR everywhere, not just on my travels or scenic outings. I like to snap the charming everyday scenes around me: a child walking his ginormous dog, a granny feeding the birds, a bit of grass making its way through the pavement – like nature reclaiming its environment … I’m even thinking of purchasing a Sony hybrid camera as it takes so much less space but offers amazing photo quality.
Anyway, I was taking my camera out for its daily stroll the other day, when I bumped into a friend, who for some reason was particularly intrigued about the device that day (she’s seen me with the thing a thousand times!). I talked her through some basics about photography and, confused, she asked if I could just write them all down? Fortunately, we know how much I love writing about things I find fascinating. SO, I’m going to write down a few photography principles. Starting with… EXPOSURE.
What is exposure?
You may have already heard of this term, without really knowing how to define it. You may have even heard of over-exposure! We’ll go more into detail on that, but it is said of a photo that it is over-exposed when it is too bright and too luminous. You can then guess that exposure is the quantity of light received by the digital sensor. Not that confusing, right?
What factors influence a photo’s exposure?
Now we’re getting a bit more technical, as 3 factors influence exposure in photography:
ISO sensitivity: the sensor’s sensitivity to light. The higher it is, the more light is captured.
Aperture: the diameter of the opening in the lens when you trigger a snap, or simply the amount of light the lens lets in onto the sensor. Same here, the more open it is, the more light you capture.
Shutter speed: the time it takes the lens to open when you trigger. When that time increases (and so, when the shutter speed decreases), it also lets more light pass through.
How do you manage a normally exposed photograph?
You can consider that there are two well distinct solutions to snap a regular exposure. The first is of course Auto Mode. Quite simple really, as your device manages all the different settings, so that the final result is correct. Nowadays, different cameras on the market are fitted with sensors that have one role: measure the image’s brightness. As such, in Auto Mode, you have a very good chance of snapping a neatly exposed photo. Needless to say, this is particularly adapted to beginners, those in a hurry, or the less demanding photographer.
The second solution will allow you to snap a photo with an exposure that depends on your needs and preferences, and it is of course to manually set those 3 parameters. Where experts perfectly know what values to choose for those parameters according to the surrounding light, an amateur will have considerably more difficulties at first. Don’t hesitate to snap several pics, each time modifying each different setting, one after the other, and checking the result to try and understand what you’ve changed. Over time, you’ll know how to change the settings to reach the desired result!
*** Notes about over- and under-exposure ***
Completely white or completely dark areas on the photos you capture? They would be suffering from an excess of light in the first case, and a lack in the second. Over-exposure, under-exposure: some of the most essential ingredients in photography!
What is over-exposure?
An over-exposed video or photo has received too much light to offer good readability. In other terms, it’s too bright! High luminosity brightens the imagine, to the point where it can turn the brightest zones completely white: these are the famous “burned” images, which receive so much light they become illegible.
What is under-exposure?
On the other hand, an under-exposed image lacks light. At night or in a dimly lit room, you’ll get a photo where the darkest zones have turned black… and just as illegible as the white zones on an over-exposed photo. We call these “blocked-up shadows”, or simply “muddy” zones.
So, how can you modify a photo’s exposure?
As I said above, you’ll need to play around with the sacrosanct “exposure triangle” that is ISO sensitivity, shutter speed, and aperture. As each element is interconnected, if you modify one you’ll most likely need to modify the others. Are there any exact settings? Afraid not! Adjustments depend on each different photo, the environment it is snapped in, the camera (they’ll have different quality sensors!) and… the photographer! Everyone operating a camera has different preferences, and just like the artist point of view, the lighting preferences vary for every photographer, amateur or professional.
In the end, the best advice I can give my friend – and you guys – is: just play around. Experiment! With digital cameras you’re obviously not wasting any film. So what do you have to lose? If you’re witnessing a rare scene and are afraid you’ll lose it before you find the right settings, just pop on Auto Mode. You’ll get a more than decent photo, and can later make a few adjustments in an editing program if you need.
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