Palermo photo basics class

PHOTO 101: BASICS

EXPOSURE & THE PHOTOGRAPHIC PROCESS When you press the button on your camera to take a picture, you are “exposing” your camera to light. You control how much light enters the camera, determining how the image will look.

If you let to much light flood in you will over expose your image, meaning it will be too bright.

If you don't let enough light in you will under expose your image, meaning it will be too dark.

This balancing act is called exposure and it's a case of juggling the 3 parts of the exposure triangle:

APERTURE, SHUTTER SPEED, & ISO

EXPOSURE TRIANGLE Think of exposure as a perfect triangle – all angles are equal, all sides are equal.

If you change one part of that exposure or triangle, it is no longer perfect so you will need to change another point of the exposure or triangle an equal but opposite amount to make that triangle and therefore the exposure perfect again

All the elements of exposure triangle have a different effect on the image, its up to you as the photographer to choose what combination of these 3 crucial elements will give you the effect you want.

ISO ISO Controls how sensitive your camera is to light.

Your objective should be to use the lowest ISO necessary to give you the settings you need because higher ISOs show more "noise" or grain. Always set your ISO first before choosing a shutter or aperture.

Low sensitivity, ISO 25 – ISO 50 Pros: Excellent definition and great contrast, the best range to use when you need to amplify an image.

Cons: Used in places with good illumination only. Think beach or studio Medium sensitivity, ISO 100 – ISO 400 The most popular range for beginners and professionals, maintains a good proportion of definition and contrast and can handle decent amplifications. Used in places with normal illumination.

High sensitivity, ISO 400 – ISO 3200 Pros: Ideal for indoor photography, night shots, concerts. When using with flash you can achieve greater depth.

Cons: Contrast and definition can be a little poor, and the big grains associated with high speeds are notable (meaning your photos can appear pixelated).

APERTURE 1.Controls the amount of light that is allowed into the camera through an opening in the lens 2.Measured in f-stops.

3.Determines the Depth of Field.

1. Aperture is an adjustable opening in the lens used to let more or less light hit the digital sensor or film.

Think of window blinds as your aperture, and the wall in your room opposite the blinds is your sensor or film. As we open the blinds, more light comes through and we can see the wall behind us get brighter and brighter. Likewise, as we open up the aperture on our lens, we get more light on our sensor or film.

2. Think of aperture openings, or f/stops, as the bottom number of a fraction. So if we have f 4 that would be 1/4 and f8 would be 1/8 and 1/4 is larger than 1/8. The Aperture numbers represent “Whole Steps� of light from one to the next. A whole step represents the doubling or halving of the light through the lens. So f1.4 will let in twice as much light as f2.0. f2.0 twice as much light as f2.8 or we can also say that f2.8 is half as much light as f2.0.

On your lens, you may see numbers in between the numbers above. Those represent 1/3 stops so we can fine tune beyond just whole stops. f/1.4 has a very wide opening, whereas f/11 is much smaller. Always remember: the smaller the numerical value, the larger the opening in the lens, and the brighter your photo will be.

3. The aperture is responsible for the Depth of Field (DOF). This is how sharp the focal point in the picture will appear, and the amount of blur that other areas will take on. The relation between the diaphragm, depth of field and f-number is pretty simple: wide open aperture, less depth of field and conversely, small aperture opening grants a greater depth of field. So, with f1.4 selected, the blades of the diaphragm are wide open letting more light pass through and we get a poor/shallow depth of field. As the f-number increases, the diaphragm blades reduce the aperture letting less light pass and resulting in a greater depth of field.

DEPTH OF FIELD Depth of field is the amount of the frame that is in focus. The degree of depth of field that you can achieve will depend on your camera, lens and available light.

Factors that affect Depth of Field: 1.Aperture 2.Distance between camera and your subject 3.Focal length of your lens (50mm, 200m etc). More on this in the advanced lesson in week 3 1. A large depth of field such as f22 will keep all or most of the frame in sharp focus, while a small depth of field such as f2 will have a smaller area in focus with the rest of the image blurred. f/4 = Large aperture. More light allowed through the lens. PORTRAITS f/22 = Small aperture. Less light allowed through the lens. LANDSCAPES 2. Depth of field is also effected by the distance that the main subject of focus is from the lens. The closer you are to your subject matter, the less of the background that will be in focus, and visa versa.

HAND EXAMPLE ☺

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ISO 100

F 2.8

SS 1/640

ISO 100

F 32

SS 1/4

SHUTTER SPEED 1. The amount of time light passes through the lens to expose the image sensor or film.

2. Affects perceive motion in images. Allows you to stop motion or highlight motion 3. Measured in fractions of a second 1.When you take a photograph, your cameras shutter opens to let light in. The shutter stays open for a period of time and then closes. This period of time is called the shutter speed.

The longer the time, the more light will hit the surface. This time directly affects the illumination degree in a photo, which is the reason we use the term underexposed when a picture is too dark and overexposed when it is too bright. In both cases the problem was incorrect exposure time.

2.shutter speed controls motion. Whether we want to freeze motion or show motion, shutter speed is the portion of exposure that will control that aspect.

3.Shutter speeds are measured in fractions of a second. For example if you see a 500 speed available, the time the shutter remains open is 1 / 500 or 0.002 seconds. A shutter speed of 2 means the shutter remain open for half a second. If you see quotation marks on the right side of a number (like 1″) it means the shutter will remain open for a full second. In some cameras you can also find a “B” or “T” speed available, these letters stand for: B (Bulb): Keeps the shutter open until you release the button.

T (Time): Keeps the shutter open until you press the button again.

SHUTTER SPEED

1/60; f/13; ISO 200

ISO 100 F-32 SS 1/4

1/500; f/4; ISO 200

ISO 100 F-11 SS 1/30

ISO 100 F-2.8 SS 1/640

How to choose your settings Ask yourself, what is your priority: motion or depth of field?

MOTION: • Do you want to stop motion or emphasize movement?

• Can you hand-hold the camera at this shutter speed and not have the slight movement of the camera show up in our image making it blurry or less sharp?

DEPTH OF FIELD: • Do you want more or less depth of field?

• How far are you from your subject?

Small aperture = Large f-stop (f/16, f/22, f/64) Large depth of field. All or most of the frame in sharp focus.

Large aperture = Small f-stop (f/1.4, f/4) Small depth of field. Main subject in focus, background and/or foreground blurred Fast shutter speed = 1/125 -1/1000 Slow shutter speed = 1/60 - 30 seconds or timed (B) Bulb exposure.

Do you have enough light to realize your vision, or must you compromise settings?

PUTTING IT ALL TOGETHER
 Every scene we view or photograph has a dynamic range: the difference between the brightest and darkest parts of your scene What we often hope to accomplish is to capture that dynamic range of the scene into our image so that the brightest part of the image (say the sky) is not too bright, and the darkest part (shadows) are not lost into noise.

Sometimes the dynamic range of a scene can exceed the dynamic range of our camera, so we have to make a choice of which part of the scene do we want to have the best exposure.

If we are shooting a portrait, we want our subject to be perfectly exposed even if that means that another part of the image my not be. Some times that is a sacrifice we have to make, if we cannot change the conditions of the shoot nor have the option of supplementing the lighting.

There is not a right or wrong method, it is simply a matter of preference, and achieving the effect that you desire The best way to completely understand shutter speed and aperture is to put your camera in Manual mode, and experiment!

Your settings will depend entirely on what you are shooting, your shooting environment, and how you want to expose your photo. If you want a shallow depth of field, but do not want to overexpose your photo, you will need a wide aperture (f/2.8, for example), and a fast shutter (somewhere around 1/125). If you want to capture a wide range of focal points, you will need a smaller aperture (f/11), and a slower shutter speed (1/80). REMEMBER, these settings all depend on your environment and what you are photographing, so be sure to experiment with different settings.

So how do you determine what settings are appropriate for you environment?

LIGHT METER

LIGHT METER Illumination is the key factor in photography; according to it we select the ISO, define the SHUTTER SPEED and regulate the APERTURE to properly expose the image sensor.

The device that measures the amount of light in the environment is your light meter. It measures the light that passes through the lens and lets us know if it is adequate or whether we need to make some adjustments. If your camera displays a photo meter you should be able to see a little indicator like the following: - 2 …. 1… . 0…. 1 ….. 2 + An indicator will let you know you if your current settings are right, normally if it’s around “0″, you are ready to shoot. If the indicator is at the right, the positive side, it means there is too much light. If it is on the left side, the negative, it means you need to let more light pass though. In both cases you can change the current ISO, shutter speed or aperture until the indicator is around the 0 – it really is up to you which one to move.

In cameras, this metering is called TTL (Through The Lens), calculating the light reflected from the object. The most common modes are matrix and spot. The first one calculates the average light in the entire scene, like pieces in a puzzle, and each one has its own value.

The second one just meters the spot you are pointing at and excludes all of its surroundings.

LIGHT METER

YOUR METER CAN BE WRONG! Light meters measure light reflecting off of an object, then calculate what it thinks the best exposure will be by averaging the tone of your picture. Sounds simple for a machine, but your meter can easily be fooled sometimes, leading to bad exposures.

Imagine that you have a black cat and a white cat sitting next to each other. The amount of light in the space AND subsequently the “correct exposure” is the same regardless of which cat you take a photo of. But if you move in close and take a photo of the white cat, your camera’s meter will give you a very different suggested exposure setting than if you had chosen the black cat. That’s because the fur of the white cat reflects more light.

Why does the camera’s meter get it wrong? The camera expects all the tones within the scene that it is metering to average out to a mid-grey (known as 18% grey). Since the two cats, one black and one white, represent the opposite sides of that scale of dark and light, the camera’s meter simply tries to average them into a middle gray colored cat instead a pure white or pure black cat, so it will always be the wrong exposure from the meter.

In practice, you may often find yourself photographing subjects that aren’t typical.

That’s when the camera gets the exposure wrong. If your subject has a lot of light tones (sand, snow, white cat, black dress, etc) your camera will underexpose the image and 24 the photo will be too dark.

CAMERA CONTROLS How do you identify SHUTTER SPEED & APERTURE on your camera?

• Most DSLRs have a dial with manual controls: PASM or P/Tv/Av/M • Take your camera out and half-press the shutter, two numbers should pop up: One might have an f in front of it (ie. f3.5) or it will be a decimal of sorts (ie. 4.0). That number is the aperture. The other number (if you're outside) should be larger, say around 200-4,000. That's the shutter speed.

BRACKETING

Bracketing allows us to cover a range of exposure settings for a single shot. You can set your camera to take a series of images according to a bracket range you specify, or you can do this manually. For example, you might setup your bracketing to make a -1, 0, and +1 (or one stop under, normal, and one stop over exposed) series of shots.

Be careful to reset or turn off bracketing when you don’t intend to use it or you might be surprised by unexpected exposure results.

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