A beginner’s guide to Aperture, ISO and Shutter Speed.

Sahil Khurana
Lenses and Papers
Published in
5 min readDec 25, 2020

Photography to begin with is a way broader thing than storing and sharing memories of your family, pets and yourself, although those are a huge part of it too. Photography is an Art, just like painting, sketching or dancing, it’s kind of like all of them combined and stored, captured on a paper to be visited again and again, whenever you want to.

I am an artist, or at least I like to think so. A regular one, if there exists anything of that sorts. I draw, and paint, and sometimes just stare at things for too long..you see art can have many explanations but we are not talking about what art is but what are the tools that every photographer, hobbyist or professional should know, aperture, ISO and shutter speed. Things get a little technical here.

A hint? all of them has something to do with light.

Wait a minute, doesn’t everything in photography? yes, the word ‘phōs’ means light in Greek, which forms the head of the word photography (in case you didn’t notice) and ‘graphé’ is capturing, representing in lines or writing. That gives us two major parts of photography, light and lines.

ISO, aperture and shutter speed all have one thing in common, hardware. Although they all essentially perform similar functions, one decides the sensitivity of a camera’s sensor, the other two makes use of a physical shutter.

Aperture is widely accepted as one of the three most important elements of photography along with shutter speed and ISO, which we will be talking about briefly.

A Camera Shutter (it’s stock).

Our eyes adjust to different lighting conditions almost constantly, pupils are at the head of this transition. As you might have learned in school, our irises, the colored part of the eye, controls the amount of light entering the eye by physically adjusting the eye’s pupil or the opening with iris through which the light enters before reaching the lenses and then focused on the retina.

A camera is much like an eye, almost eerily like one, like mentioned above the iris can be compared to the camera shutter which control the amount of light by physically adjusting the gap that allows the light to enter, it does that by either shrinking or by expanding, the pupil thus becomes the aperture of a camera. Then there is a lens that focuses and help create a clear image, then just like an eye a camera too converts the image into electrical impulses that is then sent to the brain or the processor (depending on your state of existence), through a network of connections inside of a camera and through an optic nerve in the other case.

Coming to ISO, now ISO performs almost the same function as aperture but instead of physically controlling the light it works more with the image processing or let’s say sensitivity of the camera sensor.

So we are clear that ISO controls the light, it can make a picture brighter or darker depending on your ISO settings, a higher ISO would result in a brighter picture and a low ISO would mean a darker one but with this comes the concept of grain and noise in image. When shooting in a high ISO setting if the scene is not bright or illuminated enough it can result in noise in shadows and other dark areas of a picture. In short we can say the higher the ISO, the higher the chances of more grain. Higher sensitivity detects smaller beams of light resulting in higher grain.

Notice the increase in brightness and grain with increasing ISO [source: photography life]

Now, grain is not always something undesirable, sometimes grain might help in reducing or at least hiding imperfections, to add a sort of a vintage look, enhance the theme of the photograph or simply playing with tones and colors.

While shooting a painting, for example, one can go for a ISO of 800 and adjust shutter speed and aperture accordingly, assuming the lighting conditions, this will help preserving the texture and convey the surface to the one looking at the picture.

There are significant differences between grain and noise, noise is an error, a defect and almost always is undesirable, it can be a result of external factors, a damaged sensor, temperature change, red eye, for example, is a widely known form of an external error. Basically it’s everything with light a camera mistakes in capturing. A good analogy would be a phone’s microphone, just like your phone may pick up background sounds which maybe called as background noise, so can a camera as a result of the input sensitivity.

Shutter speed in pre-click settings or increasing exposure of the picture in post edits can be another option for achieving a similar effect, but ISO provides a more natural environment to the picture, generally speaking.

Shutter speed is another interesting concept that both of the above topics, aperture and ISO rely upon, to put it in simple words a camera shutter opens for a fixed duration that allows the light to fall on the lens, it shuts soon after. Shutter speed decides the duration for which the shutter will remain open.

To test it, try 1/60 shutter speed. This means the shutter will stay open for a duration of 1/60th of a second. Different shutter speeds can be used on varied situations. In athletics, for instance, a shutter speed of 1/2000 may seem reasonable to get a steady shot of a moving object, the aperture, however, must be very low like f/16. One more use of shutter speed could be motion blur.

Astrophotography often makes use of a prolonged shutter speed, many factors play into that such as the fixed value of how long you can actually fix shutter speed for a star, the rotation of Earth, or whichever planet you are shooting from, and the crop factor of your lens. More on that some other day.

Another stock photo, for context.

For now, I think all this info should be enough for a good start in photography. You know now how light works in a camera, how light enters through a hole, for how long it does and what components play a part in forming the picture that is later transferred on to your computer and then shared with the world.

Thank you for reading this far, this medium publication in brand new with this being its first post, I hope you liked it. We’ll try to get you the best information, tips and tricks with all things lenses and papers.

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