Should I choose shutter speed or aperture first?

Question

I am learning about photography and in process of that reading few books and online resources to get some basics.

Currently i am reading "Understanding Exposure" by Bryan Peterson.While going through book, i came across few sections where he first choose "shutter speed" in place of the "aperture".

I am not sure how relevant this question is , but i am curious to know about these decision. Is there any thumb of rule for these decisions, when to go with aperture or when to go with shutter speed or it just a decision based on experience.

In All cases Camera was set in Manual mode

Answer 1

It depends on the type of photo you want to take. For example if you want to shoot a subject in motion then the main priority is to set shutter speed so you need to set it first. If you want the subject to have a shallow depth of field (for blurred background) or deep depth of field then you need to set aperture first.

In most of the cases shutter speed will do, as when you are in shutter priority mode and you set low shutter speed then camera will reduce the aperture by similar amount(same stops) itself and vice versa to compensate for change in shutter speed(provided iso is fixed).

I mostly use my camera in two modes , either in Shutter priority or in Manual mode.

Manual mode is great if you have some time to think before taking the photograph , you can control shutter speed and aperture both in it in such a way that the exposure mark is in center (EV 0) of the exposure levels(which are from EV -2 to +2) , which usually produces a properly exposed image.

I use shutter priority mode in situations where i dont have much time to think , for example while photographing birds , moving subjects etc.

You can check your image is properly exposed by checking out the histogram for each picture within the camera itself. You need to see your camera manual to find out how to display histogram for an image.

If you don't know how to interpret histograms to check if your image is properly exposed, then check out these links in order-

1 - http://www.cambridgeincolour.com/tutorials/histograms1.htm

2 - http://www.cambridgeincolour.com/tutorials/histograms2.htm

Answer 2

Aperture gives you control of depth of field, shutter gives you control of impact of movement in scene or camera movement. If you are shooting a still scene on a tripod you can set aperture to what is best, not worrying about the shutter. If subjects are moving or you are hand holding, then you need to think about shutter speed more. ISO setting of course can also figure into this equation.

Answer 3

Aperture or Shutter Speed?

Which will have greater impact on the image you want to produce is an artistic decision. Sometimes it is also a practical decision forced onto the photographer by the limits of the scene and the ability of the equipment to capture it.

The Aperture Value (Av) you select will affect the Depth of Field (DoF) of your image. DoF is basically a way to describe the distance between the nearer and further objects that appear in focus in an image. This will also be affected by things like display size, viewing distance, and even the visual acuity of the observer of the final image.

The Shutter Speed (Tv for time value) you select determines how long the image is exposed. If a scene is static, then Tv doesn't affect the composition. In that case it affects exposure when combined with aperture and ISO. But if there is motion in the scene, then the Tv you select determines how much or little of that motion is captured in your image.

The third component of the exposure triangle is sensitivity, which we often refer to as ISO. The sensitivity you select will determine which combinations of Av and Tv will result in the 'correct' exposure. Since the level of exposure may also be an artistic decision, there is no true 'correct exposure' for a given scene, only exposure values that will yield certain brightness values in the scene between shadow (totally black) and highlights (totally white). Normally we define 'correct' exposure as somewhere between the value that either yields the brightest values in the scene as highlights or the value that yields the darkest values in the scene just above shadow.

So how do you know which to select first? It depends on the scene and what you want it to look like in your photo. Sometimes there is so little or so much light to work with that you don't have much of a choice: Say a very dark scene where even using the widest Av your lens has and the highest ISO your camera has you still need a Tv longer than you would like, or a very bright scene that requires both your fastest Tv and narrowest aperture even when at your camera's lowest ISO.

Most of the time, though, the scene is not quite that extreme. Then you get to choose what is more important for you. If it is DoF then select the Av first and find a Tv and ISO that allows the exposure you want using that Av. If it is minimizing or maximizing motion in the scene, then select the Tv first and find an Av and ISO that allows the exposure you want using that Tv.

Answer 4

Without seeing the context, I think it's important to explain the different types of camera settings.

Before we had automatic exposure, the shutter speed and aperture had to be set (along with the ISO rating of the film). You were the light meter.

M - Manual mode.

You can set the aperture, shutter speed and ISO to your liking.

A - Aperture priority.

Digital cameras have a light meter and will automatically guess the shutter speed according to the aperture you set it to. This is all according to the cameras specs and will differ across all models/brands but in general, you'll get similar exposures.

Example - If you set f5.6, it will automatically set the shutter speed to 1/125 (depending on the lighting conditions). If you then set it 1 stop down to f2.8, it will set the shutter speed to 1/250.

While, at the same time if you set it to f5.6 and change lighting conditions the shutter speed will change automatically for an even exposure while the aperture will stay as a constant, hence Aperture priority.

S - Shutter priority.

Same concept, except you set the shutter speed.

While going through book, i came across few sections where he first choose "shutter speed" in place of the "aperture".

Is there any thumb of rule for these decisions, when to go with aperture or when to go with shutter speed or it just a decision based on experience.

For me, it was based on experience. For night shots and long exposures, setting the shutter speed to 1 second or up to 60 seconds and this is where you would set the shutter speed first.

Aperture changes your depth of field. If that's what you're after, a low f-stop will give you narrower depth of field.

So, really, is you're shooting in "A" or "S", you don't need to worry about getting the right exposure. Unless you want to use the EV +/-.