When learning photography, it can be tricky to understand how your DSLR works. Most of us started shooting in automatic because we did not know what we were doing when we switched our camera to manual mode.
Basically, your DSLR has four main shooting modes, they are; Program (P), Manual (M), Aperture Priority (Av/A) and Shutter Priority (Tv/S).
 The different shooting modes on an advanced DSLR. |
 Manual mode lets you control everything on your camera. |
In this article, I will try to explain shutter speed, aperture, and ISO in the easiest way possible. Hopefully, it will help you to never use automatic mode on your camera anymore. I do not hate automatic mode, but I think that it reduces your creativeness.
 Aperture Priority mode lets you control everything except the shutter speed – it will be set automatically depending on your other settings. You can control your ISO or leave it on automatic. |
 Shutter Priority mode lets you control everything except the aperture – it will be set automatically depending on your other settings. You can control your ISO or leave it on automatic. |
Manual Mode makes you think and slow down
When you take a photo in auto mode, you’re just capturing a moment objectively. For example, let’s say you’re taking a picture of a cat. Your only intention is to have the cat pictured , that’s a snapshot. Automatic mode gives you the right exposure straight away whereas in Manual Mode, you have to go through a creative process in your brain to take the image.
Let’s say you’re taking a picture of the same cat in Manual Mode, you’re not just clicking a button. You’re actually thinking about what you want to do. You might want to picture the cat with a blurred background, you might want to photograph the cat in motion or freeze the moment while it’s blinking. My point is that manual mode brings more subjectiveness to your photographs, a bigger piece of consciousness about your intent, and what you need to do to achieve the end result you want.
The problem many people have with Manual Mode, or at least I did, is how to get the right exposure. My pictures would be either over or underexposed.
Finding the correct exposure
You will have a correct exposure when you are able to create the perfect balance between the shutter speed, aperture and ISO depending on the amount of light that’s available. When you are shooting outside, your exposure will always change, let’s say you are doing a portrait session in natural light. Your exposure will change every five minutes because the light varies all the time.
Comparison between a correctly exposed image, overexposed and underexposed one (left to right).
There might be a cloud covering the sun or it may be setting, so the intensity of the light will change. In a studio session, once you get your lights positioned the way you want and have found the correct exposure, you will not need to change your settings again unless you change the position of your light and its intensity. Basically, my point is you have to consider the amount of light available, the intensity, and its direction.
A studio portrait. As soon as I get my exposure settings right, I will not change them.
Shutter speed, aperture, and ISO explained
Before I get to the main subject of this article and you finally leave the automatic mode for good, I want to explain shutter speed, aperture, and ISO.
Shutter speed
The shutter speed is the amount of time the sensor inside your DSLR is exposed to light. A faster shutter speed will let in less light than a longer one. That is why we use very long shutter speeds in low light photography. The time between the shutter opening and closing will vary depending on how much light you want in your picture.
The shutter speed controls ambient light, that is one very important thing. If you need less light, then get a faster shutter speed. Do the opposite if you need more light. A fast shutter speed will also freeze action because the picture will be taken much quicker than a longer shutter speed. This will let you control if you want a moving subject to appear in motion or frozen in your image
Using a fast shutter speed to freeze a moving sports car
Using a slow shutter speed shows cars in motion or only the light trails from their headlights.
Aperture
The aperture (opening in the lens) controls the amount of light that is let inside the camera. There is one confusing thing about apertures. A large aperture lets in more light but large apertures are translated with small numbers. In other words, an aperture of f/1.8 is a large aperture (opening) but the number is small, whereas an aperture of f/16 is a small opening but the number is big. Once you get this straight in your mind, it should be fine because the aperture is not that difficult to understand.
Basically, you use aperture for two main things. If you have low light conditions, you will need to use a big aperture (small number) to let in more light. But mostly we use aperture to control the sharpness of an image. A bigger aperture (small number) will give you a shallower depth of field (a blurred background), and a small aperture (bigger number) will give you a larger depth of field (there won’t be any blur in the background, most of the photo will be sharp).
ISO
Shot with an aperture of f/5.6 during a concert, I had no flash and had to boost up my ISO to over 1000 to get a proper exposure. I used a focal length of 50mm.
The ISO is the sensitivity of your camera sensor to light. With a higher ISO, the sensitivity to light is increased, therefore you will have more light in your photograph. One tip I can give you is not to be scared of the ISO. It does damage your photo quality wise by adding grain (noise) but with today’s DSLRs you can boost up the ISO to 1000 (or more) and still have good quality. Besides, you can always reduce noise later in post-production. I sometimes take portraits up to 1250 ISO, because I don’t really have a choice and choice is the whole point of this article.
Manual mode
Manual mode in photography is all about making choices. Sometimes use an ISO of 1250 for portraits. Most people would tell me I have no idea what I am doing if they see my settings because they’re scared of a grainy high-ISO picture. But I made the choice to use a high ISO to compensate for the shutter speed (make sure it was fast enough).
This a portrait using a large aperture of f/1.8 and an ISO of 1000, I had no flash with me and it was long after the sunset.
If I use a long focal length with an aperture of f/5.6, I will mostly likely get satisfying bokeh. A shutter speed of at least 1/125th or 1/160th is needed to avoid any blurred shots due to camera shake as my lens is pretty heavy. I really need a sharp photo, so this will make me boost my ISO to 1250 because my choice was to shoot with that lens, at that aperture and that shutter speed.
To use manual mode, you have to make artistic choices and play with the shutter speed and the aperture, leaving the ISO as an additive compensation to get the correct exposure. If you want to photograph a road with cars passing by in the middle of the day, you will most likely want a sharp photo so you will use a small aperture. You then need a fast shutter speed to freeze the cars so the ISO, in this case, will most likely be pretty high.
An image during daylight of a fast car using a fast shutter speed. The amount of light available enabled me to use a fast shutter speed with an ISO of 100 and a small aperture. If it was during sunset I would have needed to increase my ISO to compensate for the lack of light.
If you’re shooting sunsets and you want to capture some clouds moving in the sky; you will most likely use a small aperture to cut down the light, which will force a long (slow) shutter speed so you will likely need to decrease the ISO to 100. What you are doing is playing around with the shutter speed, the aperture, and the ISO to get the desired effect.
There are many ways to balance them, but each choice produces a different artistic result. It’s up to you to make that choice.
This is a long exposure of 30 seconds with an ISO of 100, the camera was placed on a tripod, I used a small aperture of f/14 for a sharp image.
Conclusion
Using Manual Mode makes you put more thought and reflexion into the photo you are about to take; I call this the artistic choice. Like I previously said, the shutter speed, the aperture, and the ISO make the photograph. Between your artistic choices, you can choose to have a shallow depth of field, a large depth of field, a subject in motion, or frozen.
Think about what you want to do before pressing the shutter button.
You can also choose how much light you want in your photo. If your artistic choice is determined by the aperture, then you have play around with the shutter speed and the ISO to find the right exposure. However, if it is determined by your shutter speed then you need to play around with the aperture and the ISO to find the correct exposure.
Note: your camera will reach its limits. But, you can use ND filters to darken your image or flash to brighten it up.
