DoF Question.....

[cgratti]

Ok, I know this has probably been beaten like a red-headed stepchild but, I have a DoF question.

1. When I shoot something at say, 1/60 - f11 and want to add DoF to the image I must "stop down" the apature, correct? If I stop it down to say f22 what should I change the shutter speed to?

2. Is there a set formula for figuring this out? Or is it just trial and error?

[SoCal69]

Ok, I know this has probably been beaten like a red-headed stepchild but, I have a DoF question.

1. When I shoot something at say, 1/60 - f11 and want to add DoF to the image I must "stop down" the apature, correct? If I stop it down to say f22 what should I change the shutter speed to?

2. Is there a set formula for figuring this out? Or is it just trial and error?

If you are going from f/11 to f/22, you are halving the aperature area twice (i.e, 1/4 of the light is entering the camera). You will need to double the shutter speed twice (the shutter speed should be 4 times longer to let in 4x as much light) to maintain the same exposure. So you would set shutter speed from 1/60 to 1/15.

Each full f-stop (moving to smaller aperatures) halves the area of the aperature (half as much light enters the camera). Therefore you will need to double the length of the shutter speed to let in twice the light. This way the amount of light entering the camera (i.e. your exposure) remains the same.

[Guillermo Freige]

2. Is there a set formula for figuring this out? Or is it just trial and error?

Of course there is a formula, and there is a lot of programs using it :)

Just search for "DoF calculator" in Google and you'll find a lot of links. I even have one installed in my Palm :)