Camera ISO Basics

A real quick history lesson

Back in the day when cameras were designed to use film, ISO referred to how sensitive a roll of film was to light. Photos shot on a roll of film with a higher iso number would need less light hitting the film to end up with a photo that is properly exposed.

When it comes to modern digital SLR cameras, we no longer use film because it has been replaced by camera sensors, but similar rules still apply. Instead of having different types of camera film that are more and less sensitive, Digital camera’s are able to adjust their sensor ISO setting to act more or less sensitive to light.

The general “Rule of Thumb”

Unlike a camera’s shutter speed or aperture, there is no real creative advantage of changing a camera’s ISO setting.

A general rule of thumb is to always have as low of an ISO setting as possible while still having your photos properly exposed.

The higher the ISO setting, the more you introduce noise into your photos. This is the tiny speckling effect that looks like static in a photo and it is typically avoided as much as possible. On a quick side note, make sure that you do not confuse the photography terms “noise” and “grain”. Although they may seem similar, grain refers to the speckling effect from film photography which is sometimes intentionally added, while noise is only introduced in digital photography and is considered a negative in photos.

How ISO effects the look of your photos

A camera will always take its best photos at what’s called it’s “native ISO” or “base ISO”. For the majority of camera this will be either 50 or 100 ISO. The further away from a camera’s base ISO you get, the more noise will appear in your image.

As much as possible, you want to avoid changing your ISO setting to extremely high digits like 50,000 or what some photographers call “Swiss cheese mode” because the amount of noise will ruin your photos.

Every camera is different depending on their age and sensor, but usually noise will start to become more obvious and distracting at ISO settings over 2,000.

So what is the benefit of adjusting the ISO?

The main purpose of adjusting a camera’s ISO higher is to allow for faster shutter speeds in low light environments. You can think of it as the more sensitive your camera sensor is the quicker you can freeze movement. With that being said, if you are taking photos mid-day or in direct sunlight, there is not much of a reason to set your ISO to anything higher than the Base ISO.

In my next article I’ll talk a little more about the exposure triangle which is the relationship between a cameras aperture, shutter speed and ISO and how they all work together to take a photo! Thanks for reading and be sure to leave a comment if you have any questions!

Shutter Speed Basics

Today we’re going to be talking a bit about shutter speed and how it effects your photography, so if you are new to an SLR camera or typically use it on automatic, this will give you a better understanding about shutter speed.

What is “Shutter Speed”?

Shutter speed refers to how long a camera is letting light hit its sensor while it takes a photo. This length of time is adjusted using the “shutter” on a camera. A shutter on a SLR camera is similar to a tiny set of blinds that open and close to let light through.

Every time a photo is taken on an SLR camera, the shutter moves out of the way to let light hit the sensor when you press down on the shutter button to take your photo, and then the shutter stays open for the amount of time you specify before closing again and finishing the photo. On a side note, that is why the main button on a SLR camera that takes the photos is called the “Shutter-Release Button”

Similar to how wider apertures allow more light through the lens when taking a photo, slower shutter speeds allow light to hit the camera’s sensor for a longer period of time.

Where do find your Shutter Speed?

When you look at the back screen on most SLR cameras, you’ll see that the shutter speed is measured in seconds indicated by the “inch” symbol. If the current shutter speed is set to be quicker than a full second, the shutter speed will be displayed as a fraction of a second.

Entry level, beginner SLR cameras tend to have one screen to show all of the relevant information on the back of the camera, but you are also able to view a very minimal version of your camera settings including the current shutter speed by looking through the viewfinder. The numbers and symbols that light up across the bottom of your viewfinder window will allow you to know these settings without the need to stop taking photos.

When you are using a mid-range or professional SLR camera, these tend to have a secondary screen on the top on the camera that shows basic settings as well without the need to wake up your main screen and save some battery life.

Motion Blur vs Freezing the action

Unless your camera is stationary, like on a tripod, your camera will have more motion blur the slower your shutter speed goes. There are lots of charts that exist out there to show at roughly what speed a shutter can freeze different types of movement, but the best way to learn these settings is to simply take photos with your camera on “Shutter Priority” mode and play around with different shutter speeds with moving subjects.

Typically shutter speeds one second or slower are reserved for long exposure photography. A slow shutter speed or “long exposure” photo is used for things such as astrophotography or making moving water appear smooth.

In these cases, photographers will use a tripod to keep the camera perfectly still while taking the photo so that only movement in the scene they are shooting will appear blurry.

A faster shutter speed is used to freeze fast moving action in like in sports photography or splash photography.

Understanding stabilization

You can get away with taking sharp photos handheld at slower shutter speeds that normal when a lens or camera has optical or digital stabilization included in it. Keep in mind however, that optical/digital stabilization only helps with a shaky camera. It does not freeze fast moving subjects like fast moving athletes or wildlife.

Around half of the camera’s and lens being produced today have some form of stabilization built into them. When a lens has optical stabilization built into it, there is usually a switch on the lens to give you the option of turning the stabilization on or off. I recommend leaving the stabilization on in most cases so that the glass elements in the lens move slightly and help you stabilize your shaky photos. The one time you should remember to turn off lens and camera stabilization off is when you are taking photos on a tripod, otherwise the stabilization can lead to softer images. The same rules apply to camera bodies that have optical stabilization built in, except for with cameras, the stabilization comes from the physical sensor in the body moving slightly to compensate for camera shake.

The general “Rule of Thumb”

A quick and easy rule of thumb for taking handheld photos is to always make sure your shutter speed is the same or quicker than the focal length you are shooting at. If you have any form of optical stabilization turned on you can use even slower shutter speeds, but this is a great starting point for reference. So if you are taking a photo with a 100mm lens, be sure to have your shutter speed set to a minimum of 1/100th of a second.

Thanks for reading and be sure to leave a comment if you found this information useful or if you have any questions!

Camera Aperture Basics

In it’s simplest form, the aperture in a camera lens is the size of the hole in the lens that allows light of varying amounts to pass through the lens to hit the sensor in a camera body. You can think of a lenses aperture similar to a person’s iris (the coloured part of an eye). When you are outside and it is really bright out, your iris adjusts by making your pupil smaller to let less light into the back of your eye. When you are in a dark movie theatre on the other hand, your iris adjusts to make your pupil in the centre of your eye much larger to let in as much light as possible so that you have the best chance of seeing in the dark. Now take that information, but replace a person’s iris with a lenses aperture and you will quickly understand how an aperture works.

What is a F-Stop?

The aperture (or the small blades that form the lens’s aperture) are always adjusted using something called f-stops. f-stops typically start around f-1.2, and go all the way up to around f-30 or f-40.

So as an example, if you have a lens that opens up to f-1.4 as an aperture setting, this means that it is opening up very wide and is letting in a large amount of light through the lens to hit the camera’s sensor. On the other hand, if you have a lenses that only opens up to f-3.5 or so, that means that there is less light going through the lens and hitting the camera’s sensor.

If you are currently using an entry level SLR camera, most likely it came with what is known as a “kit lens”. Kit lenses are inexpensive lenses that typically don’t open up very wide when it comes to their aperture. On the flip side of things, if you spend more money on a “professional” lens like the Nikkor 50mm 1.8 or 1.4 lenses, you will have the ability to let more light through the lens which is referred to as being a “fast lens”.

One thing to keep in mind is that the wider the aperture is able to go on a lens, the more expensive it tends to be. This is because when lenses let it more light, the lens requires a larger aperture and physically more glass to accommodate.

Why change the aperture?

There are two very specific reasons why you would want to change the aperture setting on a camera. The first reason, which I have already mentioned, is to allow more light through the lens to hit the sensor on the camera. The second reason is a much more stylistic choice. The easiest way to remember it is that the more open an aperture setting is on a lens, the more blurred the background will be behind you or your subject. And on the opposite side of things, if you close down your aperture to a very high number, say f-20 or f-30, the majority of your scene or subject will be in focus.

Depth-of-field

The “depth-of-field” is a fancy term to describe how much of a photo is actually in focus. For a quick example, in the linked video, I am using an f-2.8 lens behind the camera. For this series of videos I am using this lens at it’s maximum aperture of f-2.8 so that I can be seperated from the background by having the background out of focus.

On the other hand, you may require a really high f-stop for something like product photography. For product photography, photographers typically want the product to be fully in focus. If were to take a photo with a wide open aperture of a product, where you focused on the product would be in focus, but everything else would have varying levels of being out of focus.

A lenses “Sweet Spot”

One last thing to keep in mind. With a few exceptions, the majority of lenses are sharpest (and therefore give the highest quality results) around the middle of their f-stop settings. If you are using a kit lens for example, if it goes from f-3.5 down to f-20 or so, it may be a good idea to start shooting at around f-8 because that is when your lens is typically sharpest and go from there.

If you take away only one thing from this article, just remember that a small f-stop number will actually let in more light into your camera. A lot of people starting out with photography will get this point mixed up and reverse it (since that would seem more logical!)

Thanks so much for reading this article about photography! If you found this article useful or if you have any questions for us please be sure to leave a comment below!