DOF Question?

[Hardrock]

Probally a stupid question but obviously when using a macro lense at f2.8 the depth of field is very shallow due to the working distance between the lense and subject, correct? So does that mean when using a telephoto like a 200mm or 300mm at f2.8 does the dof of field increase?

 

[chris]

Other way round, for a given aperture the depth of field reduces with increasing focal length.

Check out a DOF calculator such as Online Depth of Field Calculator.

 

[Hardrock]

So basically yes if Im reading it correctly. Using a 100mm at 10in from the subject gives you a .02in dof and at 10ft a .32ft dof. So the further the subject the more the dof increases.

 

[Plato]

So basically yes if Im reading it correctly.

Here's more detail than you ever want to know!

 

[Hardrock]

Thanks guys! I think I understand now its the subject to camera working distance not the focal length that affects the dof. So with any lense at f2.8 the further you are from the subject the more dof you will have.

 

[epp_b]

Other way round, for a given aperture the depth of field reduces with increasing focal length.

Actually, it's the decrease in focus distance caused by the increase in focal length. Longer focal lengths typically mean that you focus closer. Macro lenses focus extremely close and, therefore, have depths of field measured in microns.

 

[Samanax]

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