Aperture Vs Shutter Speed...balancing act?

You're correct about shutter speed. A shorter shutter speed can "freeze" the action while a longer shutter speed allows for fun effects with moving objects (light painting, getting motion blur, taking dreamy shots of waterfalls, etc.).

Aperture is also very important! The aperture, in addition to controlling how much light enters your camera, also controls your depth of field. This means: what is the depth of the area in your shot that is in focus? A large aperture gives a shallow depth of field. An example would be a portrait where someone's eyes are in focus but their nose and ears are not. A small aperture gives a larger depth of field, in some cases, extending from some point a few feet away to infinity. This is good for landscape shots, as one example, where you want both near and far objects to be in focus.

As you experiment more with photography, you should study what aperture and shutter speeds are used to make a particular shot, and it will give you a clue how they work together. Experienced photographers can look at a scene, visualize what they want the final outcome to be, and select aperture and shutter speed to achieve the look they want.

Good luck and have fun!

 

Two suggestions.

Aperture priority will be more important when you are shooting certain types of photos. For example, if you are going to combine (stitch) several photos you would want a consistent depth of field. The same would be true for shooting HDR.

 

also know that increasing you aperture size, will also lower you dof. While stopping down you will have greater dof.

 

You need to read
Amazon.com: Understanding Exposure: How to Shoot Great Photographs with a Film or Digital Camera (Updated Edition) (9780817463007): Bryan Peterson: Books

 

I may start another "discussion", but here it goes anyway.

1. There are actually three factors involved, when shooting digitally, not two. Shutter speed (S), aperture (A) and ISO. Changing any one of these changes exposure in some way. Each also affects the image in other ways like.......

2. Shutter speed is the "stopping power" of a camera. You use it to deliberately stop or blur motion. The setting required depends on the subjects speed, angle of motion distance to the subject and the desired effect. Moving the camera during exposure is also a factor here (panning or camera shake for example).

3. Aperture describes the "depth of field" of a shot. Smaller number, smaller DOF. From a fixed shooting position DOF changes with the aperture set and the focal length used. If shooting with a fixed subject size (in the frame) then only changing the aperture changes DOF as the movement of the photographer and the change of focal lengths (to keep the subject the same size) cancel each other out.

4. ISO was not an often used factor in the film days, but is super useful in digital as it's easy to change. The higher the ISO the more the sensor is amplified. This means an increase in exposure. The trade off is that the higher the ISO the more "noise" there is in an image. There are other things that affect noise as well, the main one being heat. Most, if not all m4/3 cameras have less noise at 1600 ISO than film had (grain) at 400 ISO.

So yes it's a balancing act, but it's a three way one. As sensors get less noisy we, as photographers, are able to have more control over balancing stopping power and depth of field now that we can change ISO's on the fly. It doesn't have to be one or the other. Often we can have both.

Gordon

 

Excellent point Gordon. ISO was not such a big issue in the days of film or even early digital but the new sensors offer a big range of usably clean ISO. It makes things much more flexible (but also more complicated for beginners).

 

Try this interactive demo which shows the result of varying iso, aperture, shutter, various camera modes etc: cameraDemo

Richard

 

Yes, Gordon pretty much nailed it. I still highly recommend you read Understanding Exposure as it provides pictures and examples of what we're talking about, and how to use the settings to make the photograph match your vision of what it should be.

Suffice it to say:
- if DOF is important, set the camera to A mode. Smaller f/stop number = bigger lens opening = less of the scene in focus => faster shutter speed

- if action is important, set the camera to S mode. Faster shutter speed = stopped motion => bigger aperture

- you can shift/balance the aperture and shutter speed selections by using the ISO. Higher ISO means less light needs to hit the sensor for a given exposure. So, for a given aperture, the shutter speed will be faster at higher ISO. For example, if you want a large depth of field (small lens opening) AND to be able to stop motion (fast shutter speed), you will need a high ISO to end up with a properly exposed image.