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P, A, S, M, Manual Shooting Modes and Exposure Explained

P, A, S, M, Manual Shooting Modes and Exposure Explained - If you've ever wondered what P, A, S, or M stands for on your camera, then this article is for you. We explain the shooting modes on a camera, including shutter priority, aperture priority and more.

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K-1 Mark II in Digital Camera Operation

Nikon D7000 DSLR Mode Dial

Whether you have a compact camera, a mirrorless camera, a DSLR or even a smartphone, if it has manual controls, then you'll want to understand the different modes available. 

To help understand your camera more, you'll benefit from learning what the P, A, S, and M modes do on your camera.

But first we need to start with some basics. A photograph's exposure is made by the camera sensor (or film) being exposed to light for a specific amount of time. This is refered to as the shutter speed. The shutter speed is determined by the amount of light that is needed for a correct exposure. The amount of light that reaches the sensor is controlled in part by the aperture of the lens. In addition, how sensitive the sensor is to light is controlled by the ISO speed. If you were using film, this would be fixed, by your choice of film speed. 

To take a photo, a camera must set the aperture (of the lens), the shutter speed, and the ISO speed. This can be either automatically set by the camera, or you can set these manually if your camera has the controls available. Have a look at the "Exposure Triangle" below:

Exposure Triangle

ISO Speed = the image sensor's sensitivity to light

Aperture = lens aperture opening, allowing light through

Shutter speed = the length of time the shutter is open


If you're setting these manually, you can increase the ISO speed to make the camera more sensitive to light, (and in return you'll also get more noise in images), with a higher ISO speed you can use a faster shutter speed (to freeze motion), or use a smaller aperture (such as f/11, or f/16) to get a wider depth-of-field where more of the scene will be in focus.

Hopefully this has helped understand how a camera takes a photograph. Continue reading to find out more about the different modes, and how changing them can change the results you get from your camera. There are alternative triangles available.

 

Canon Powershot SX740 Dial P8150001

 

Camera shooting modes explained

Some cameras have a mode dial, as shown above and below, whereas others let you change the mode by pressing a Mode button, or by selecting the "Pro" mode (on a smartphone). Continue reading to find out all about the different modes, or jump straight to a mode using the links below. 

Auto | Program | Aperture | Shutter | Manual | TAv | SvFv | Movie

 

 

Auto Mode and Exposure Compensation 

In auto mode, your camera looks at the scene and decides what ISO speed to use, what shutter speed to use, and what aperture to use. If you are taking a photo and it looks over-exposed (too bright), then you can use exposure compensation (EV+/-) to adjust the camera's exposure, to make the image darker or brighter.

Some cameras will have an Auto+ / A+ / Ai / iAuto - an "intelligent" auto mode that will change to a specific scene mode or shooting mode for you to give you the best results. In these modes you may find the camera limits what settings you can change. 

 

Panasonic Lumix GX7 Mode Dial P8150003

 

P - Program mode

Program or Program AE, stands for Program Auto Exposure, where the aperture and shutter speed will be set by the camera, much like the Auto mode on most cameras. However, in this mode you can change other settings, such as AF point, metering mode, etc. 

Normally a camera with P mode, will let you use "Program Shift" where you can turn a dial on the camera to change the shutter speed and aperture settings, for example if you'd prefer a quicker shutter speed or a smaller aperture. 

 

 

A / Av* - Aperture priority

The aperture of the lens controls the amount of light that goes through the lens. It's normally made up with several "blades" that close and open in the middle of the lens. 

Nikon 50mm f/1.4 aperture open to close
Nikon 50mm f/1.4D lens, f/1.4, f/4, f/16. 

To make a subject stand out in a photo, and blur the background you can use a wide-open (f/1.4) aperture, or to keep everything in focus from front to back, you can use a small / "closed down" aperture such as f/16 or f/22. The higher the f/ number, the smaller the aperture hole will be. 

 

Wide-open aperture, vs Stopped down aperture

Left: Lens at f/1.8 (1/800s, ISO100), shallow depth-of-field. Right: Lens at f/22 (1/4s, ISO100), deep depth-of-field.

The larger the aperture (the smaller the f/ number), the less of the scene that will be in focus, and the more blur there will be - this can give you better subject separation (between the subject and the background), and create pleasing background blur, often referred to as "Bokeh". The smaller the aperture (the bigger the f/ number), the more of the scene that will be in focus, as shown above, right.

 

Nb. Most smartphones don't let you control the physical aperture of the lens, as they often have a fixed aperture. One exception is the Samsung Galaxy S9 / Note9 with a variable aperture, with two different settings. Some smartphones use a digital filter to re-create the effect of having aperture control. 

*Av on Canon and Pentax cameras

 

 

S / Tv* - Shutter priority

You can adjust the shutter speed if you want to create motion blur to smooth waterfalls, or trailing lights, or use a faster shutter speed if you want to freeze motion, such as racing cars, people, or sports.

 

Fast shutter speed, vs slow shutter speed
Left: 1/500s (Fast) Right: 50s (Slow)

The shutter speed is how long the shutter is left open for. 1/60s means the shutter is open for 1/60th of a second. A 1 second exposure means the shutter is open for 1 second. Use a faster shutter speed to freeze motion. 

There's a general rule regarding shutter speed that goes like this: When you are hand-holding a camera, then the shutter speed should at least match the focal length. For example if you have a 50mm lens, then you should use 1/50s shutter speed (or faster) to avoid camera shake. If you have a 200mm lens, then you should use a 1/200s shutter speed (or faster) to avoid camera shake. Nb. This rule changes if your camera has image stabilisation. 

If you're shooting in changeable lighting conditions then you, can use this rule to set the shutter speed, and let the camera automatically change the aperture and ISO speed to suit, and then avoid potential camera shake. 

Bulb mode - if your camera has it, lets you leave the shutter open for an undefined amount of time, so that you can open the shutter, wait for something to happen (such as a lightning strike, or just wait for the sensor to get enough light), and then release the shutter to finish the exposure. 

 

*Tv stands for Time Value and is found on Canon and Pentax cameras.

 

 

M - Manual mode

In manual mode you can control both the aperture and shutter speed to get the settings just how you want them. On some cameras you can leave ISO on auto, or manually set the ISO speed. Keep an eye on the screen and you'll be able to see how your changes affect the exposure, as most cameras will show how much you are under or over exposing your image.

Pentax K 1 Ii Mode Dial
Pentax K-1 II Mode Dial

 

TAv (Pentax cameras)

This lets you adjust the shutter and aperture speed, and the camera will automatically change the ISO speed. Again, most cameras will let you use "Auto ISO" in other modes, so this may not be needed, depending on your camera, however could be useful if you wanted to keep the ISO speed as a manual setting in the other modes. Find out more on the TAv mode.

 

Sv (Pentax cameras)

ISO speed priority. Set the ISO speed, and the camera will set the other settings for you. This mode is not so useful these days, as you can often set the ISO speed easily in other modes. 

 

Fv (Canon EOS R)

Flexible Priority AE shooting mode - this is like a Program / Auto mode, but with adjustable shutter, aperture, ISO, and exposure compensation. So you can shoot quickly, and then have the option to change any setting you want, without having to switch to A, S, or M modes. The camera starts in P mode, but you can change any setting, or set it back to auto. Canon explain this mode fully here.

 

Movie mode

The movie mode is fairly self-explanatory. Use this mode to record videos. Some cameras will let you select P, A, S, M modes within this. The amount of control available will vary depending on the camera you're using. It can be useful to switch to this mode before recording video, so that you can preview the framing of your shot before you start recording, as the aspect ratio of video recording is often different to the normal shooting modes.

 

Canon EOS 600D Mode Dial P8150004
Canon EOS 600D Mode Dial 

 

Other shooting modes: 

  • Custom - Many cameras will have customisable shooting modes: U1, U2, U3 (Pentax/Nikon), C1, C2, C3 (Olympus / Panasonic), 1, 2, 3 (Sony) etc. Set these up for specific shooting scenarios, and then you can quickly switch between them. 
  • Bulb - some will have a B or Bulb option on the mode dial. Some will have this option selectable in Shutter priority or manual modes. This lets you take a photo with a long exposure, where the shutter is open for as long as you need it to be.
  • Scene - choose the appropriate scene mode for what you are shooting, shooting a Sunset, then choose the Sunset scene mode and it will set the white balance and other settings so that your photo looks the same as your eyes see it. Scene / Auto - some will feature an auto scene recognition setting, where the camera automatically picks the scene mode detected.
  • Effects - Many cameras have digital filters, which you can selection. Art (Olympus) / Effects (Nikon) / CA (Creative Auto, Canon) etc
  • A-DEP (Canon) - This is short for "Automatic Depth of Field" and is designed to give the maximum depth-of-field. It's no longer found on new Canon cameras, but was available on some older Canon cameras. 

 

 

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Comments


7 Nov 2018 1:20PM
I've been using Program Mode almost exclusively since NIkon invented Variable Program somewhere around 1996. Not sure the exact date of Variable Program but it was a big improvement from normal Program. As the name implies, you can change what the camera has selected by simply turning the rear dial right for a faster shutter speed or left for smaller aperture. Whichever direction you go, the shutter speed and aperture follow each other. If you want to stop action, dial it right. Better depth of field? Dial it left. Almost all cameras have this functionality now with Canon being somewhat of an exception. Yes, Canon allows for changing what the camera had selected like Nikon, Lumix and others. But... when the Canon cameras go to sleep and you eventually touch the front shutter button to wake the camera up, the camera will have gone back to what THE CAMERA wants to shoot at. Not what you set it to. This can be an issue when let's say you're photographing an eagle in a tree along the Chilkat River in Alaska. You're on tripod, the eagle is just sitting there. You want good depth of field so the beak is in focus as well as the tail, so you shoot at F/8. When done with the portrait you know the eagle is going to eventually fly so you take the rear dial and go right to set the shutter speed to 1/2000th of a second. As you wait for the eagle to fly, your buddy asks you what you think about the new #LumixG9 so you start shooting the breeze. All of the sudden the eagle sees a fish and jumps from the tree. You quickly go to your camera, touch the front shutter button, the camera wakes but if it's Canon it has rest itself to 1/250th at F/8. Not the 1/2000th you had set it to. The eagle flies and your action images are now very soft. Thats the caveat of Program on the Canon system and it's been that way since the EOS 1 from what I know. Not sure why they've not fixed this but just one good example of a camera company having a closed mind and ears apparently. If you want more about how to use Variable Program you can find additional info at http://naturalexposures.com/?s=program+mode

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