Have the letters and icons on your DSLR camera’s mode dial ever seemed cryptic to you? Have you wondered why there are all these different types of modes and which one suits what kind of photography best?
This post discusses the four main exposure program modes available in your camera, which allow you to choose which factors of the exposure triangle (aperture, shutter speed and ISO) you’d like to control, and when you must choose which one and why.
This dial of your DSLR camera comprises a variety of letters, each one signifying a particular type of the exposure program mode:
P – Programmable Automatic Mode
A – Aperture Priority Mode
S – Shutter Priority Mode
M – Manual Mode
This table illustrates what aspects of the exposure triangle is controlled by you and the what are controlled by your camera in the various modes.
Automatic (Auto) Mode
The mode in which most cameras come set out of the factory is the completely automatic mode, which we strongly recommend you to avoid using and here is why.
Which mode should you use then? Read on.
Programmable Automatic (P) Mode
In this mode, the camera chooses the aperture and the shutter speed automatically but you can override its decisions for one picture at a time. Since you’ll need to set your preferred aperture or shutter speed for each picture, therefore, we do not recommend this mode. The ISO, however, can be set either manually or automatically.
Aperture Priority (A) Mode
In Aperture Priority Mode, you control the aperture and ISO, and the camera controls the shutter speed for the right overall exposure. In this mode, you have full control on depth-of-field, which is inversely proportional to aperture. In other words, the greater the aperture, the shallower the depth-of-field and vice versa.
This frog image shot on our Costa Rica Wildlife Photography Tour illustrates this scenario:
Also, the largest possible aperture can achieve the fastest possible shutter speed, so by using this mode, you can also indirectly control the shutter speed.
The following picture of a tiger charging at a dove, shot on our Bandhavgarh Wildlife Photography Tour
Shutter Priority (S) Mode
In shutter priority mode, you get to control the shutter speed and ISO while the camera figures out the aperture value to maintain a balanced exposure. You switch to shutter priority mode when you want to blur something deliberately. This is the mode that allows you to make stunning panning shots and capture the movement of vehicles and make the flow of waterfalls look silky smooth, because for these types of shots, you need a specific shutter speed, unlike for sharp pictures where you just need a minimum shutter speed.
The waterfalls example is illustrated by the following photo, shot on our Iceland Landscape Photography Tour
However, if there isn’t enough light, using a fast shutter speed will lead to underexposure of the image. While Auto ISO might be a good solution for this problem, you will lose control over the depth-of-field since you’re relinquishing control over aperture.
Manual (M) Mode
When you wish to capture star trails and long exposures of any kind, you can switch to manual mode, as you will have control over aperture, shutter speed as well as ISO.
Also, in most cameras, the bulb mode is within the manual mode, and it allows you to make really cool pictures of lightning cleaving the night sky, stars leaving their astral trails, fireworks and light-painting!
If you wish to learn photography on field, under the real-time guidance of our ace Photography Mentors, join one of our Photography Tours!