Primary reason for choosing an aperture?

I saw a post the other day on another forum where the person said, "The primary reason for choosing an aperture is the depth of field", and then went on to exclaim about the benefits of an f/1.8 prime because of the amount of light it lets in.

He went on to talk about different f stops and the fractions of light they let in

1/2, 1/4, 1/16, 1/32, etc.

I have read about how using f/1.8 enables you to use faster shutter speeds so that you can capture movement in dim light, but f/1.8 is not going to give you very much depth of field

So, does choosing an aperture depend on how much light you are shooting in?

In good light, choose an aperture because of the depth of field it will give you, and in dim light, choose an aperture because of the amount of light it will let in?'

Whats your primary reason for choosing any given aperture?

There's the whole issue of background blur, but that's not what I'm interested in.

Steve Thomas

stevet1 wrote:

I saw a post the other day on another forum where the person said, "The primary reason for choosing an aperture is the depth of field", and then went on to exclaim about the benefits of an f/1.8 prime because of the amount of light it lets in.

He went on to talk about different f stops and the fractions of light they let in

1/2, 1/4, 1/16, 1/32, etc.

I have read about how using f/1.8 enables you to use faster shutter speeds so that you can capture movement in dim light, but f/1.8 is not going to give you very much depth of field

So, does choosing an aperture depend on how much light you are shooting in?

In good light, choose an aperture because of the depth of field it will give you, and in dim light, choose an aperture because of the amount of light it will let in?'

Whats your primary reason for choosing any given aperture?

My primary reason depends on subject, lighting, what lens I'm using and what shooting mode I'm using. Sometimes, I'm primarily interested in using a particular shutter speed and let the camera set the aperture. Sometimes, in low light and when I want to keep the ISO setting low, I'll shoot wide open and accept less depth of field as the lesser of evils compared to added noise.

So, what I'm saying is that my reason for choosing or accepting a particular lens opening depends on the  situation and what I'm trying to do. I don't have a consistent primary reason.

There's the whole issue of background blur, but that's not what I'm interested in.

Steve Thomas

Steve,

In general, when I'm not shooting a moving subject, I generally just leave the lens aperture at what I know will give more-or-less the sharpest photo (presuming there are no other issues). I almost always shoot in A (AV) mode.

If I want blurred backgrounds, I go for the smallest aperture and get as close to the subject as possible.