Beginners Guide to ISO, Aperture and Shutter Cover

Beginners Guide to ISO, Aperture and Shutter

It is difficult to take good photographs if you don’t understand ISO, Aperture and Shutter. These three things are the major settings of photography which is also called Triangle Exposure. However, latest DSLR’s have auto modes that select the right shutter speed, aperture and even ISO for your exposure. In many cases, camera has to guess what the right exposure should be by evaluating the amount of light passes through the lens. Simply if a photographer has learned how to play together with these settings, photographer can take charge of the situation by manually controlling the camera.


Let’s just have an overview on:


 ISO is the level of sensitivity of your camera to available light. The lower the ISO number, the less sensitive it is to the light, while a higher ISO number increases the sensitivity of your camera. The part within your camera that can change sensitivity is called Image Sensor.



A device that controls the amount of light enters through an opening. Aperture is the unit of measurement that defines the size of the opening in the lens which can be adjusted to control the amount of light reaching the image sensor.

Shutter Speed:


You press the shutter button from camera to capture an image. Blades of the aperture take specific time to close. This specific amount of time is known as Shutter speed.

If you are very sensible about your photography and want to bring your photography to next level then you must read out this article: 

"Different Questions you should Ask Yourself before taking a Picture"

How these exposure triangles work?

To have complete guide about exposure and how shutter speed, aperture and ISO affect it, you should know first what happen in camera when a picture is taken.


If you point a camera at a subject and press the shutter button to take picture. The subject gets into your camera in a form of light. If the subject is enlightened well a plenty of light travel into the lens, same as if you are in dim area then a small amount of lens travels into the lens. The light enters the lens and passes through various optical elements made of glass, then moves to the lens “Aperture”. Then the shutter opens for milliseconds which lets the light hit the camera sensor for a specific amount of time this specific amount of time is called Shutter speed. Then sensor gathers the light based on sensitivity which is also known as ISO. Then the shutter closes and the light is completely blocked to reach the camera sensor.

If you want an image to be properly exposed that it is not too dark or too bright, shutter speed, aperture and ISO needs to play together. Lots of Light is blocked when light enters through very small aperture so this means the camera sensor would need more time to collect the light. What needs to done with sensor to collect the right amount of light? Off course, the shutter needs to stay open for bit long period of time. So, with small lens aperture more time will be required, that is longer shutter speed for the sensor to collect enough light to produce a properly exposed image.

Now what will happen if the lens aperture is so big? Obviously an excess amount of light would hit the sensor and we will need a very shorter shutter speed for the image to be properly exposed. If the shutter speed is too slow, the light would start “overexposing” the image because the sensor would get a lot more light than it need. The overexposed area of the image will look very bright. In contrast, if the shutter speed is way too high, the image would appear “underexposed” or too dark because the sensor is not able to gather enough light.

What Camera mode you should use?

Before you read this paragraph out you should read out “Guidelines to Understand Digital Camera Modes”, I recommend using “Aperture Priority” mode for beginners. In this mode you set the lens aperture, while the camera guesses the right shutter speed for you. You can also control the depth of field in you images by changing the aperture. Mostly people end up using Auto/Program modes without knowing what happened inside the camera. That is why I recommend everyone to learn how to shoot in all camera modes.

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Nikon D610 DSLR with Nikkor AF-S 24-120mm ED VR Lens£1339.99 £1499.99

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Increase ISO or use Flash?

It always depends on what you are taking a picture of. Sometimes it is not possible to use built-in camera flash in low light environment. Let’s take an example, if the subject is far away from you and you may not be able to reach the subject with your flash the only solution in this scenario is to either come closer to the subject or turn-off the flash light and use the higher ISO. Apparently for landscape photography, you have to turn-on the flash to brighten up the entire scene and in low light situations there are only two options either set the ISO at lowest number or use tripod.

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