DSLR Exposure: Apperture Shutter Speed and ISO Sensitivity

DSLR Exposure :  The Best Combination!

DSLR Exposure: Apperture, Shutter Speed, ISO – With the sophistication of Very large scale integration (VLSI) we have seen that many exceptional camera features have started cropping up in our smartphones. They are solely the reason for the extinction of point and shoot cameras(apparently) from the market. But take my words there is nothing competing a DSLR. Consider this, the image generated by  a 18 MP DSLR  is way better than  a 30 MP camera featured in any flagship smartphone.

About DSLR-

DSLR ExposureWhat is so special about DSLR’s? The answer lies in its mechanism of operation. Digital Single Lens Reflex (DSLR) camera has a reflex scheme.Here, light travels through the lens, then to a mirror that alternates to send the image to either the viewfinder ( eye-level, where the photographer sees his object that needs to be captured) or the image sensor (where the object gets captured in digitized form). This sets it apart from other digital cameras. What you see in the viewfinder is almost exactly what you capture. Stunning isn’t it. Also the size of the sensor in a DSLR is way larger than in other digital cams. This gives it larger resolution and sharpness in a image and. Hence, better quality and fine images.

DSLR Exposure

Much said, let us emphasis on DSLR Exposure. What is it and Why is it so important ? Exposure is the term representing Aperture, Shutter Speed anjd ISO in a camera. Aperture, Shutter Speed and ISO commonly known as the “Exposure Triangle” are the “3 Kings Of Photography”. To utilize a DSLR efficiently you should  have a good knowledge about the DSLR Exposure. As the DSLRs now days are smart enough to do the most of the work automatically.  While most new DSLRs have “Auto” modes that automatically pick the right shutter speed, aperture and even ISO for your exposure, using an Auto mode puts limits on what you can achieve with your camera. It also restrains your skills on handling a DSLR.

Know how to adjust the settings (DSLR EXPOSURE) of your camera , to  push it to its limits. However, having an abstract knowledge on DSLR Exposure is also sufficient enough  for the begginers. As you start gaining experience, you are sure to master your DSLR. Much said, now lets go for the definition of this “3 Kings of Photography”.

Definition of Aperture, Shutter Speed, ISO-DSLR Exposure

-> Aperture- It controls the area over which light  enters the camera. This is a hole within the lens, through which light travels into the camera body. Its analogy can be the Iris in a human Eye Anatomy. It controls the amount of light entering the human eye through the eye lens. The larger the hole the more light enters the camera. In newest DSLRs, the aperture also controls  the depth of field, which is the portion of a scene that appears to be sharp. If the aperture is very small, the depth of field is large, while if the aperture is large, the depth of field is small. We will  discuss about the Depth of field later. Aperture is represented in ‘f’-stops( ‘f’ for focal ratio) or ‘f- numbers. Examples of f-numbers are: f/1.4, f/2.0, f/2.8, f/4.0, f/5.6, f/8.0.

-> Shutter Speed- This determines the duration of the exposure. It controls the length of time and amount of light exposed to the camera sensor. Shutter speeds are generally measured in fractions of a second, and sometimes in seconds . Slow shutter speeds allow more light into the camera sensor, while fast shutter speeds help to freeze motion. Examples: Faster Shutter Speeds- 1/10, 1/15, 1/60 , Lower Shutter Speeds- 2, 8, 30 .

-> ISO Sensitivity- The level of sensitivity of your camera’s sensor to the incoming light.  This affects the noise in the image. By noise we mean the graininess produced in your image. ISO  is generally measured in numbers, like 100,200, 400 etc. Lower ISO represents lesser sensitivity to the light and larger ISO represents higher sensitivity to the light.  However, larger ISO number increases the noise in the image and thus less sharp image.

Now let us get into more details.

DSLR Exposure- Aperture

Aperture is the area over which the light enters into the camera sensor through the camera lens. The f-stops used to specify the aperture in the camera settings are very weird. The area of the opening increases as the f-stop decreases. So less the f-number, more is  the area over which the light enters the camera. Aperture setting also  determines a photo’s depth of field (the range of distance over which objects appear in sharp focus). Lower f-stop values corresponds to a shallower depth of field.  This is used to give more style or creativity to your shoot.  Lower Aperture ( Higher f-stop) the objects in the foreground and background are in focus. Higher Aperture (lower f-stop) foreground are in focus while the background becomes blurry.

Ways to use Aperture ?

  1. Lower f-stops or Higher Aperture– This varies between f/1.4 – f/2.8. More area of light to enter , so photos can be taken with faster shutter speed. Also it isolates the foreground from the background. Examples : Bird Photography.
  2. Higher f-stops or Lower Aperture– Varies from f/4 to f/8. Less area for light to enter hence prefer slower shutter speed. Examples : Landscape photos, Nature photography.
DSLR Exposure

High Aperture


DSLR Exposure

Lower Aperture

DSLR Exposure – ISO Sensitivity

ISO is the sensitivity of the camera sensor towards the incoming light allowed by the camera lens and shutter. It correlates 1:1 to the light. This means as the ISO level doubles, the camera’s sensitivity to light doubles. Hence increasing the noise or graininess in the picture. So it’s always advised to keep the ISO at it’s lowest instead of the “Auto”. When the light is too dim only then you increase the ISO sensitivity.

Ways to use ISO ?

  1. Lower ISO- This can be ISO 100,200,400 and 800. When the amount of light is abundant. Least noise or almost nothing. Thus, when zooming in  the picture the clarity and sharpness is intact. Example: landscape photo during the day.
  2. Higher ISO- Ranges from 1600-12000. Only in adverse cases when the light is too dim. More noise is produced.  When Zooming in the picture blurred pixels can be seen. Hence, sometimes the charm of DSLR is not seen.  Example: Capturing dawn and dusk.
DSLR Exposure

ISO Sensitivity

DSLR Exposure- Shutter Speed

This controls the duration of time for which the shutter is open, to allow camera sensor to be exposed to light. The speed of shutter  also correlates 1:1 to the light. This means that the amount of light entering the camera doubles as the shutter speed halves. The speed of the shutter plays a very vital role in picture exposure. It can make a picture look underexposed ( very fast shutter speed) or overexposed ( slow shutter speed). So maintaining a balance is necessary. Shutter speed is measured in fraction of seconds and in seconds also.

How to use Shutter Speed?

  1. Very Slow Shutter Speed- Can be 1,2 or up to 30 seconds. Used when light is too dull or dim. Taken with high ISO sensitivity. Example: Birthday cutting scene when all the lights of the room are off with  only the candle burning.
  2. Slow Shutter Speed- Can be 1/2, 1/4 , 1/8 etc . Used to add artistic feature like blur to a moving objects. This is one of the best ranges for a shoot. And is mostly used to shoot moving objects with zoom.  Examples: Water Fall, your dogs picture while he is running, also to capture a bird while she flies.
  3. Fast Shutter speed– Ranges from 1/50 to 1/500. Used to freeze fast moving objects. A sharp image with no blur gets generated. Also used for burst modes. Example: Capturing the bowling action of a bowler, to capture the goal kick of your son.
DSLR Exposure

High Shutter Speed

DSLR Exposure- Exposure Modes

DSLR have many  exposure modes – DSLR Exposure. These modes are Av ( Aperture Priority), Tv ( Shutter Priority), P ( programmed mode) and M ( manual mode). For the beginners I highly recommend the use of Aperture Priority (Av). Here the photographer specifies the aperture and the camera automatically determines the shutter speed for optimal effect. Now, I hope you learned a lot from our post . To assist you more I have attached some statistical tables to remember .

Shutter SpeedTypical Examples
1 – 30+ secondsSpecialty night and low-light photos on a tripod
2 – 1/2 secondTo add a silky look to flowing water
Landscape photos on a tripod for enhanced depth of field ( Higher Aperture)
1/2 to 1/30 secondTo add motion blur to the background of a moving subject
Carefully taken hand-held photos with stabilization
1/50 – 1/100 secondTypical hand-held photos without substantial zoom
1/250 – 1/500 secondTo freeze everyday sports/action subject movement
Hand-held photos with substantial zoom (telephoto lens)
1/1000 – 1/4000 secondTo freeze extremely fast, up-close subject motion

Aperture Setting

Relative LightExample Shutter Speed
f/221X16 seconds
f/162X8 seconds
f/114X4 seconds
f/8.08X2 seconds
f/5.616X1 second
f/4.032X1/2 second
f/2.864X1/4 second
f/2.0128X1/8 second
f/1.4256X1/15 second

I have added a link of a video for you to see. Enjoy and all the best

Also Read – Horse Algorithm Question – Everyone is baffled


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