I’ve been around photography for a long time. You hear all kinds of conversations.
One of the ones I hear a lot revolve around the PASM modes on the more advanced camera systems.
Today we are going to :
Discuss the different modes, how and when to use them (or more accurately how and when I use them) and other techniques that revolve around the different modes.
PASM is what you see on the main dial of most interchangeable lens cameras and some advanced fixed lens cameras.
P = Program
This is a type of mode where most of the exposure decisions are made entirely by the camera. The beauty of this mode is the ability for the photographer to do what is called “program shift”.
When your camera reads a scene, it used the light meter built into it to try give you a proper exposure. It sets the aperture, shutter speed and ISO accordingly. If you don’t like the exposure chosen for you, you can use a command dial on the camera to “shift” the parameters.
Why would you want to use program mode and shift?
Maybe you are on vacation or just learning and you don’t want to have to think about anything. Just get some nice snapshots. Program mode is great for that. Where the “shift” feature comes in handy is for times when you may want to adjust the the shutter speed or aperture momentarily.
Perhaps you see a scene and the 18-55mm kit lens on the camera gives you a 1/100, f/5.6, ISO 100 exposure reading. The subject you want to capture is of a person jogging down the street. You know from experience that they will most likely be blurry and having a faster shutter speed would fix that. 1/250 would be great for this. You click the command dial to shift the exposure to 1/250 and the aperture to f/4.
An equivalent exposure is selected now, but you have the settings you need to freeze the action of the runner.
A = Aperture Priority
This is the mode I use most often. Why? I like to be in control of the depth of field in a scene more so than other modes.
By controlling the aperture, the camera will then select an appropriate shutter speed to get an accurate exposure.
I normally have the ISO set to auto and let the camera adjust the ISO from base up through 6400 if using an APS-C or m43 size sensor. If using a larger sensor (say like a 135 or Nikon FX), then I might let it go 1-2 stops of ISO higher if needed.
Panasonic 20mm f/1.7 II – 1/1250, f/1.7, ISO 200
1/400, f/2.8, ISO 200
S= Shutter Priority
I use this mode when shooting sports or fast moving subjects. In similar creative ways like you use the aperture size you can use the shutter speed to freeze the action or do a move called dragging the shutter. Dragging the shutter can be used for getting blurred motion.
One example may be putting you camera on a tripod and getting that silky smooth water in a stream or waterfall
A second example may be getting the blurred motion of hands and feet to give the sense of motion.
A third reason that I also use shutter priority is a gear reason. On my m43 gear, I love the small size and the reach that the EM1 and the Olympus 75-300mm lens give me.
The only catch is that the the field of view can be challenging for that lens to get stable shots at the longer end, even with the great IBIS in those cameras. So, what I do is I use the camera/lens combo in good light and try and not use the a shutter speed slower than 1/500.
This ensures me a higher chance of getting images that are not blurry equivalent focal lengths of 600mm.
I almost gave up in that Oly 75-300 because I was convinced that we was a poor performer at the longer focal lengths. Glad that turned out to not be the case.
Nikon Z6
0.8s, f/4, ISO 1600 (handheld)
Olympus OMD EM5 Mark II
1/20, f/2.8, ISO 1250 (handheld)
M = Manual
Manual mode is a way to use the camera in a way that makes the exposure meter a tool of suggestion and not something that takes control and needs to be overridden.
I frequently will use manual mode with auto ISO. Seem a little counter intuitive at first, but remember how we discussed how we can creatively control the way an image looks in A and S modes?
This allows us to get the depth of field we want and the level of frozen action or blur we want together.
Whenever I use off camera flash, the mode of choice is manual without auto ISO. I want to control every aspect of the scene and sculpt the lighting to be on a subject a certain way.
1/250, f/4, ISO 400 in conjunction with off camera flashes
1/125, f/6.3, ISO 200
Bonus Tip – ISO/Auto ISO
For the longest time, I never used the auto ISO mode on any of my cameras. I was too worried that the camera would pick too high an ISO and I’d get an unnecessarily noisy picture.
First, the modern cameras of today have great high ISO performance. As mentioned above, I’ve got no issues going all the way up to ISO 6400 on any camera I have and use.
Secondly, auto ISO frees you up creatively, especially in manual mode. Now it does seem counter intuitive that you’d use auto ISO in a manual mode. However, manual with auto ISO lets you lock down the aperture and shutter speed but vary the ISO as needed.
Why do this?
Here is a scenario for you and one I’ve run into many times. I’ve an event I cover annually which is an outdoor 5k obstacle course/run. I need to isolate the subjects from the wooded backgrounds, but they are running and/or traversing obstacles. I use the wider aperture to isolate along with an appropriate focal length and a fast enough shutter speed to handle freezing the action. One element that I cannot control is the natural environment. At times, I’ll have cloud cover hit and we go from complete sun to complete shade. I’ve also had instances where I am tracking a subject from a sunny spot into an area with tree cover and the canopy can cause a 1-2 stop light difference.
If I were shooting full manual, I’d need to adjust the ISO myself when the athletes were going through the various lighting conditions. Using auto ISO, I can let the camera do that shift for me. It does it way quicker than I could and I have found it to be accurate.
You can also handle any over or under exposure in auto ISO by doing a quick exposure compensation change. The camera will then only shift the ISO value if the meter is not giving you the exposure you want.
Olympus OMD EM1
1/400, f/2.8, ISO 5000
Handling the changing lighting conditions
Nikon D500
1/320, f/5.6, ISO 400
Handling the changing lighting conditions
Nikon D500
1/250, f/3.2, ISO 800
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