DSLR Camera Basics and Settings

DSLR Camera Basics and  Settings

#Mode settings

 

P, S, A, and M Modes (Exposure Modes)

Shooting modes fall into three categories: auto, scene, and P, S, A, and M modes. In auto and scene modes the camera controls shutter speed and aperture. P, S, A, and M modes are known as exposure modes and give photographers a choice as to which elements of exposure—aperture or shutter speed—they wish to control.

・Mode P (Programmed Auto)

The camera automatically adjusts aperture and shutter speed for optimal exposure, but the photographer can choose from different combinations of aperture and shutter speed that will produce the same exposure. This is known as flexible program.

・Mode S (Shutter-Priority Auto)

The photographer chooses the shutter speed and the camera automatically adjusts aperture for optimal exposure.

・Mode A (Aperture-Priority Auto)

The photographer chooses the aperture and the camera automatically adjusts shutter speed for optimal exposure.

Note: that in all three modes—P, S, and A—exposure is automatically adjusted for optimal results.

・Mode M (Manual)

Mode	Shutter Speed	Aperture
P (programmed auto)	Selected by camera	Selected by camera
S (shutter-priority auto)	Selected by photographer	Selected by camera
A (aperture-priority auto)	Selected by camera	Selected by photographer
M (manual)	Selected by photographer	Selected by photographer

C hoosing the Right Shutter Speed in Mode S
In mode S, the photographer controls shutter speed and the camera automatically adjusts aperture for optimal exposure. Given, however, that the range of shutter speeds available is extremely large—for example, from 30 s to 1/4,000 s, under certain conditions there may be shutter speeds at which no possible aperture setting could produce optimal exposure.
For example, if you select a fast shutter speed such as 1/4,000 s for a dark interior shot, the time the image sensor will be exposed to light will be too short for optimal exposure even if the lowest f-number is used to ensure that the image that falls on the sensor during that time is as bright as possible, and the photograph will be too dark (underexposed). In this case, the aperture display will show “Lo.” On the other hand, if you select a slow shutter speed such as 1 s for a brightly-lit outdoor shot, the time the image sensor will be exposed to light will be too long for optimal exposure even if the highest f-number is used to ensure that the image that falls on the image sensor during that time is as dark as possible, and the photograph will be too bright (overexposed). In this case, the aperture display will show “Hi.”

Underexposed

Overexposed

When shooting in mode S, note the range of apertures supported by the lens to avoid over- or under-exposure.

Sample Camera Displays

camera information display

Exposure mode:

Represented by the letters “P” (programmed auto), “S” (shutter-priority auto), “A” (aperture-priority auto), or “M” (manual).

Setting Exposure: Shutter Speed and Aperture

Two of the factors that determine exposure—and thus the brightness of your photographs—are shutter speed and aperture (the other important factor in determining exposure is ISO sensitivity, but in the discussion that follows we will assume that ISO sensitivity is fixed).

Shutter speed is the time the shutter is open. The faster the speed, the shorter the time the shutter is open, and the shorter the time the image sensor is exposed to light. The shorter the time the image sensor is exposed to light, the darker the resulting photograph. On the other hand, the slower the shutter speed, the longer the time the image sensor is exposed to light, and the brighter the resulting photograph.

Aperture (expressed as an f-number) controls the brightness of the image that passes through the lens and falls on the image sensor. The higher the f-number, the darker the image projected on the image sensor, and the darker the resulting photograph. On the other hand, the lower the f-number, the brighter the image projected on the image sensor, and the brighter the resulting photograph.

Exposure is determined by the combination of shutter speed and aperture (f-number).

If you increase the f-number, you can still achieve optimal exposure by choosing a slower shutter speed. To put it another way, if you lower the f-number, you can still produce a photograph of the same brightness by choosing a faster shutter speed.

High f-number, slow shutter speed

Low f-number, fast shutter speed

Different combinations of shutter speed and aperture used to achieve the same exposure.

Sample Camera Displays

camera information display

Shutter speed:

Speeds faster than one second are shown as fractions (e.g.: …1/125, 1/160, 1/200, 1/250…). Some cameras may omit the numerator so that “1/125” becomes “125,” “1/250” becomes “250,” etc. Speeds slower than one second are shown by a double prime symbol following the value (e.g.: 1 ˝).

camera information display

f-number:

f-number is shown in steps of 1/3 EV, for example f/4, f/4.5, f/5, f/5.6, f/6.3, f/7.1, f/8 etc.

Shutter Speed

Shutter speed is a measurement of the time the shutter is open, shown in seconds or fractions of a second: 1 s, 1/2 s, 1/4 s … 1/250 s, 1/ 500 s, etc. The faster the shutter speed, the shorter the time the image sensor is exposed to light; the slower the shutter speed, the longer the time the image sensor is exposed to light.

If you are photographing a subject that is in motion, you will get different effects at different shutter speeds. Fast shutter speeds will “freeze” motion, while slow shutter speeds introduce blur from two sources: camera movement (camera shake) and subject movement (for information on this topic, see “Camera Blur and Motion Blur”). In other words, the faster the shutter speed the easier it is to photograph the subject without blur and “freeze” motion and the smaller the effects of camera shake. In contrast, slower shutter speeds are suited to suggesting the motion, such as that of flowing water or other moving subjects. Changing the shutter speed gives you control over whether to “freeze” or suggest motion.

n the photograph taken at a fast shutter speed, the walker appears “frozen” in mid step. This is due to the fact that only a brief instant of the walker's motion was recorded because the shutter was only open for a short time. In the photograph taken at a slow shutter speed, the walker is blurred. This is due to the fact that the walker moved while the shutter was open.

Fast shutter speed

Slow shutter speed

Expressing Subject Movement

Fast shutter speeds freeze motion.

Slow shutter speeds suggest motion.

Shutter Speed Values

Shutter speeds change as shown below.

Choosing a shutter speed one step faster than the current shutter speed (by, for example, changing shutter speed from 1/60 s to 1/125 s) is referred to as “increasing shutter speed by one step” and halves the amount of time the shutter is open. Choosing a shutter speed one step slower than the current shutter speed (for example, by changing shutter speed from 1/125 s to 1/60 s) is referred to as “slowing shutter speed by one step” and doubles the amount of time the shutter is open.

If you are using a Nikon DSLR Camera, shutter speed changes in 1/3 steps; some models also support increments of 1 step and 1/2 step.

Camera Blur and Motion Blur If the camera or subject moves while the shutter is open, the picture will be blurred. Blur caused by subject movement is referred to as “subject blur” or “motion blur”; blur caused by camera movement (“camera shake”) is referred to as “camera blur.” The results in both cases are similar, but whereas blur caused by subject movement is generally regarded as a legitimate way of expressing motion in photographs, blur caused by camera shake is frequently seen as a flaw. While camera blur does not necessarily render a photograph a failure, caution should be observed to avoid unintentional camera blur. The main subject is in both cases blurred, but the results are distinct from blur caused by the subject being out of focus (focus blur).

Camera blur

The camera moved while the shutter was open, producing blur.

Motion blur

The main subject moved in the wind while the shutter was open and is blurred; the surrounding flowers and leaves, which were at rest while the shutter was open, are not.

Out-of-focus shot (focus blur)

The camera is focused not on the flower in the center but on a flower further back.

Intended result

The central flower is in focus.

Sample Camera Displays

camera information display

Shutter speed:

Speeds faster than one second are shown as fractions (e.g.: …1/125, 1/160, 1/200, 1/250…). Some cameras may omit the numerator so that “1/125” becomes “125,” “1/250” becomes “250,” etc. Speeds slower than one second are shown by a double prime symbol following the value (e.g.: 1 ˝).

Combining Aperture and Shutter Speed

The combination of aperture (f-number) and shutter speed determines exposure (another important factor in determining exposure is ISO sensitivity, but in the discussion that follows we will assume that ISO sensitivity is fixed). Choosing higher f-numbers correspondingly darkens the image that falls on the image sensor, but you can still achieve optimal exposure if you slow shutter speed in proportion. On the other hand, you can also achieve optimal exposure by choosing a lower f-number and a faster shutter speed. In other words, there are many combinations of aperture and shutter speed that will produce the same exposure. For example, suppose the subject will be correctly exposed at an aperture of f/4 and a shutter speed of 1/250 s. The correct exposure will then also be achieved if you increase the f-number to f/5.6 while slowing shutter speed to 1/125 s. The same is true at f/8 and 1/60 s and at f/11 and 1/30 s.

Combinations of aperture and shutter speed that will produce the same exposure as f/4, 1/250 s

Aperture	F16	F11	F8	F5.6	F4	F2.8	F2	F1.4
Shutter speed(seconds)	1/15	1/30	1/60	1/125	1/250	1/500	1/1000	1/2000

If you always adjust shutter speed to match any changes in aperture, you can achieve correct exposure at any aperture or shutter speed. Note, however, that changing aperture also changes depth of field, while changing shutter speed alters the appearance of moving objects. In other words, you can also adjust aperture for depth of field or shutter speed to produce the effect of motion.
*The distance in front of and behind the focus point that appears to be in focus is referred to as “depth of field.”

High f-number, slow shutter speed
The slow shutter speed blurs the jets of water in the fountain; the high f-number increases depth of field, bringing the background into focus.

Low f-number, fast shutter speed
The fast shutter speed appears to stop the water in its tracks; the low f-number reduces depth of field, blurring the background.

Aperture

Aperture controls the brightness of the image that passes through the lens and falls on the image sensor. It is expressed as an f-number (written as “f/” followed by a number), such as f/1.4, f/2, f/2.8, /f4, f/5.6, f/8, f/11, f/16, f/22, or f/32.

Changing the f-number changes the size of the aperture, changing the amount of light that passes through the lens. The higher the f-number, the smaller the aperture and the less light that passes through the lens; the lower the f-number, the larger the aperture and the more light that passes through the lens. For example, changing the aperture from f/4 to f/5.6 halves the amount of light passing through the lens and halves the brightness of the image that falls on the image sensor.

Changing the f-number also changes the distance in front of or behind the focus point that appears to be in focus. The higher the f-number, the greater the distance in front of and behind the focus point that appears to be in focus; on the other hand, the lower the f-number, the shorter the distance in front of and behind the focus point that appears to be in focus. The distance in front of and behind the focus point that appears to be in focus is referred to as “depth of field.”

Photographing the Same Scene at Different Apertures

Changing the aperture changes depth of field.

High f-number (increased depth of field)

Low f-number (decreased depth of field)

f-numbers

f-numbers change as shown below.

Raising the f-number one step is referred to as “stopping aperture down a step ” or “stepping aperture down an f-stop.” This halves the area of the aperture (or opening), halving the brightness of the image that falls on the image sensor. Lowering the f-number by one step is referring to as “stopping aperture up a step ” or “stepping aperture up an f-stop.” This doubles the area of the aperture (or opening), doubling the brightness of the image that falls on the image sensor.

If you are using a Nikon DSLR Camera, f-number changes in 1/3 steps; some models also support increments of 1 step and 1/2 step.

Sample Camera Displays

camera information display

f-number:

Shown as f/4, f/4.5, f/5, f/5.6, etc.

 

Exposure Compensation

Exposure compensation is used to alter exposure from the value selected by the camera, making photographs brighter or darker.

In modes P, S, and A, the camera automatically adjusts settings for optimal exposure, but this may not always produce the exposure the photographer intended. Exposure is a matter of personal preference, and an exposure brighter or darker than that selected by the camera may sometimes better reflect the photographer's intent. The feature used in such situations is called exposure compensation. DSLR Cameras allow you to check the results immediately, so you can take a photograph, display it in the monitor, and then raise exposure compensation for brighter results or lower exposure compensation for darker results and take another picture.

A dark, backlit subject

The same subject brightened with positive exposure compensation

Sample Camera Displays

camera information display

Exposure compensation:

Displayed as …–1.0, –0.7, –0.3, 0.0, +0.3, +0.7, +1.0…, where “–1.0” is one step darker than the optimal exposure value selected by the camera.