Depth of field (DOF) youtube video

[obewan]

Just to share a very nice video from youtube on depth of field.
It will cover

1) Distance to subject
2) Focal length
3) Aperture (f-stop)

how these 3 things will affect the DOF.

[video=youtube;34jkJoN8qOI]http://www.youtube.com/watch?v=34jkJoN8qOI[/video]

Hope this video will help people who are new to the subject on DOF, to understand, and better control of their camera to take
better pictures

 

[patrick76]

This is good and easy to understand but I have a question..

Can we draw any quantitative relationship between these factors?

I am using a crop body canon DSLR and my friend is using a full frame canon DSLR and we are both using sigma F1.4 DG lens. In order to achieve similar depth of field and assuming that both cameras have the same F-stop setting, I believed I need to stand further away from the subject in order to have similar depth of field . Alternatively, I can use a larger F-stop to have similar depth of field if I am standing at the same distance from the subject as my friend.

The question is how far from the subject as compare to my friend and what F-Stop to use?

 

[catchlights]

The DoF will be the same when both of you using the same lens, same aperture setting, shooting the same subject at the same distance.
But since you are using a smaller size sensor camera, so your field of view is nerrower, to have the same coverage, you need to stand further away from your subject.
Once you move further away from your subject, you alter the DoF, you will have deeper DoF compare to your friend using the same aperture setting.
So what if both of you already using the widest / biggest aperture? There isn't any bigger aperture for you to use.
Hope this explaination is clear enough.

 

[Octarine]

The question is how far from the subject as compare to my friend and what F-Stop to use?

Use the many DoF calculators online to get the answer. You can change all factors and see how it woks out. Using the formula you can also do the reverse calculation to find the necessary distance for a given lens/sensor/aperture.