Lesson 1 :: Know Your Camera - Understanding Exposure
Alright ladies and gents. Here it is. Hopefully the first of a good bunch of lessons to help you better understand your cameras and take more pleasing photographs of all the work you put into your Fetts (and everything else in between!) The first thing we are going to look at is
exposure. Exposure is essentially how light or how dark the image is when viewed (not highlights and shadows, this is different). The goal of every photograph should be to try to replicate what the photographer sees through the camera. For most, you probably use some form of auto - either you let the computer control the shutter, the aperture, or everything. This way, the computer judges based on environment what it thinks is a properly exposed image. Here is a brief diagram of how a camera receives information, and a few examples of ill-exposed photographs.
Overexposed Image:
Underexposed Image:
One of the first steps to have complete control over this is to get off the auto and switch to manual! Scary, I know. But don't worry, you'll get there
But before we do that...we have to talk about something else... one of the more obvious, but easily cast aside points....knowing your camera!
What kind of camera do you have? A point and shoot? Camera phone? (D)SLR? Regardless of what tool you are working with, you need to be sure of its capabilities and its limitations. There are reasons why expensive gear is so costly – it has fewer limitations.
For instance, ever take a blurry photo in a poorly lit convention hall? It’s quite possible that your camera didn’t have a flash option (or wasn’t selected), or that your shutter speed was too slow. Or what about taking a non-stalkerish picture of a celebrity from across the street, but when you looked at your display it was extremely small and grainy? Chances are your camera’s zoom wasn’t strong, and to make up for the slow shutter speed and aperture, the auto in your camera increased the ISO.
These are all limitations that your camera can experience based on the quality of camera that you have. Typically camera phones have the most limitations primarily because they are a phone, internet browser, mail client, text messenger, accountant, socializer, and angry birds application first before a camera. Point and shoot cameras are next in line for their limitations, although they have improved greatly over the years. When digital first came out, I remember being so stoked to get a 2 megapixel Sony Cybershot. More on megapixels and the ongoing war later. Last in line are the DSLRs, and even they have separate categories (Entry Level, Enthusiast/Hobbyist, Professional). Get to know what you are working with. Read the manual inside and out, backwards and frontwards. Know what your camera is capable of in terms of its aperture, shutter speed and ISO limitations so when you a take a picture you’ll understand why it turned out the way it did.
Aperture? ISO? Shutter? These voodoo words are all part of the triangle of exposure in photography. It doesn’t matter what you’re shooting, you need to understand how to properly expose a photograph before you start chucking your seemingly useless camera into the ocean. The camera is only part of what makes a photographer. The rest is knowing how to use the gear and work with what you have.
Aperture
Similar to that of the human eye, the aperture is actually part of the camera’s lens. The wider the aperture, the more light is able to enter the camera and hit the camera’s sensor. The smaller the aperture, the less light that goes in. Ever walk into a dark room? What happens to our pupils? They dilate to let more light in! And when we walk outside and get blinded? Our pupils constrict to let less light in. Eg: Check out that scene in Jurassic Park where the idiot kids shine the light into the T-Rex’s eye.
So when we are in a dark room, we need to
open the aperture to allow the camera sensor to soak in more light. When we are outside on a sunny day, we need to
close down the aperture to let less light in so we don't blow out the photo.
Examples of apertures:
ƒ/# 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32
A higher f-number = a smaller aperture = less light
A lower f-number = a larger aperture = more light
Shutter Speed
On film cameras, when you pressed the shutter button, a gate would open for a period of time that actually exposed the film to the light coming through the lens. This concept has moved to the digital age, but only DSLRs have a physical shutter that ‘ca-chunks.’ Point and shoots and camera phones only have the shutter ‘sound’…a beep....or even barking dog…Whatever your preference is
Having a faster shutter speed exposes the film (or sensor for you digital folks) for less time, freezing the subject. Longer shutter speeds can blur the image because the light is dragged along the sensor.
Light trails (slow shutter speed, small aperture, on a tripod!):
Freezing Motion (Fast shutter - optimal conditions = 1/4000s, but chances are you might have to fight with 1/500s with your aperture and ISO):
Motion Blur/Freezing Action (Slow shutter but PANNING WITH THE SUBJECT while it's moving):
Aperture and shutter speed work together because in order to create a properly exposed image, enough light has to be hitting the sensor. If the aperture is too small and the shutter too fast, the result is a completely black image. If the aperture is wide open and the shutter too long, the image is way too bright! There has to be balance between these two. BUT there is one more to throw in the mix before finding your Zen state.
Examples of Shutter Speeds
1/1000s, 1/500s, 1/250s, 1/125s, 1/60s, 1/30s, 1/15s, 1/8s, 1/4s, 1/2s, 1s
Fun fact: Generally, to avoid any camera shake (where the shutter is slow enough that it reads your hands shaking the camera) you will want a shutter speed equal or greater to the focal length of your lens...OR...use a tripod!
Camera Shake:
While we mostly will be photographing still objects (props) I won't get into photographing action much. It's pretty complex, and takes time to master as more weight is being put on balancing your exposure to get crisp imagery.
ISO
Again, back in the days of film, you had to buy film based on certain lighting conditions. This film reacted (or absorbed light) faster or slower based on the type that you bought. If you were shooting in darker areas, you’d want to buy ISO 800 film because the film was more sensitive to light and absorbed it faster. ISO 100 film was used for bright sunny days because it reacted slower.
Examples of ISO:
ISO 50, 100, 200, 400, 800, 1600, 3200, 6400+
The newer DSLRs are not just focused on improving megapixels, but ISO quality. Generally, when you increase the ISO, you add a significant amount of grain (or digital noise) to your photographs. By improving the quality of the ISO at higher values, you are able to photograph without flash in darker areas than ever before.
(This camera was on a tripod with a slow shutter speed. That's how the photographer was able to get a night shot at ISO 100!)
In a nutshell, we have three things we need to consider when properly exposing manually:
a) the light coming through your lens, b) how long your sensor is exposed to light, c) how sensitive your sensor is to the light.
When you have all these three down, you will start creating properly exposed pictures. So the next time you want to throw it on auto, play around with your camera’s manual function and make some mistakes. It’s the only way you will learn what exposure is really about!
Manual Exposure
So, you wanna play with Aperture, Shutterspeed and ISO individually? Let's see what happens in your camera.
For now, let's just look at the modes that generally appear on your camera dial:
P - Programable Auto
A - Aperture Priority (You control the aperture, the computer takes care of the rest - good for portraits)
S - Shutter Priority (You control the shutter, the computer takes care of the rest - good for action that needs to be frozen)
M - Manual
For the sake of this lesson, we will only look at Manual.
When in manual mode, you will have a light meter in your viewfinder.
You will notice in your camera's viewfinder that it says the shutter speed, aperture, and ISO among other things (shots remaining, battery, white balance, etc.).
What you will do, is based on your lighting conditions, and the effect that you are going for, increase/decrease your aperture and shutter to get your dial to the optimal exposure center.
NOTE: This will NOT always be the best exposure. This is based on the camera's metering - how it is interpreting the light coming back from the subject. For best results, you will want an external light meter to read the light falling ONTO the subject....but this is getting ahead of ourselves. Also note that with some cameras the overexpose and underexpose (+ and -) may be reversed depending on your camera. This can be changed depending on your preference in your camera settings.
It is best to set your ISO first based on your lighting conditions - Low number for sunny, mid number for overcast, high number for interior. For now, if you just want to practice with aperture and shutter, there's no shame in leaving your ISO on auto
Stay tuned next time where we get into depth of field, composition and framing, among other camera tricks
EDIT: More info added! Whew!
EDIT: Photos used are not mine this time and were found on Google for educational purposes