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09-30-2013, 06:43 AM   #1
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Depth of field

Can someone direct me to a graph that will help me understand the optics of macrophotography? I'd like to see graphs of DOF vs working distance to the subject for a 35mm lens at all the F-stops.

09-30-2013, 07:18 AM   #3
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Welcome to the Forum!

Generally Depth of Field (DoF) is primarily a function of a few physical items in the camera. Sensor size, aperture, focal length and then distance to the subject.
  • Sensor size - Small sensors (as found on Point and Shoot cameras) have a difficult time in capturing shallow depth of field. They are very good for having everything in focus most of the time. The larger the sensor, the more control you have on the depth of field
  • Aperture - The aperture provides the main approach in terms of controlling depth of field. A large aperture (f1.2, 1.8, 2,....) provides a thin depth of field, while a large aperture (f11, f16, f22) provides a deep depth of field. After a certain point (around f11 - f16) diffraction starts and you are loosing the sharpness within the frame.
  • Focal Length - Generally wide angle lenses (shorter focal lengths) have deep depth of field, while telephoto focal lengths (longer) exhibit the shallower depth of field.
  • Distance - Distance does play a factor in this, in terms of where the actual focal plane is, with the depth of field placing an envelope around this where things tend to be in focus. Regardless of the depth of field - the focal plane (i.e., where the focus is defines actually what is in focus.
The links below have calculators, tables and in a couple of cases graphs, however - you need to supply the information for your particular situation of interest. The calculated information is for general cases. Macro is going to be a function of distance, with the shorter distances getting into the close focus situations. In terms of macro, you need to realize that with macro lenses magnification comes into play also.With an interest in Macro, you need some additional information. You can add in extension tubes or bellows (adding focal length for a lens), focal rail (controlling the distance to the object), etc.
09-30-2013, 07:33 AM   #4
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QuoteOriginally posted by interested_observer Quote
Welcome to the Forum!

Generally Depth of Field (DoF) is primarily a function of a few physical items in the camera. Sensor size, aperture, focal length and then distance to the subject.
  • Sensor size - Small sensors (as found on Point and Shoot cameras) have a difficult time in capturing shallow depth of field. They are very good for having everything in focus most of the time. The larger the sensor, the more control you have on the depth of field
  • Aperture - The aperture provides the main approach in terms of controlling depth of field. A large aperture (f1.2, 1.8, 2,....) provides a thin depth of field, while a large aperture (f11, f16, f22) provides a deep depth of field. After a certain point (around f11 - f16) diffraction starts and you are loosing the sharpness within the frame.
  • Focal Length - Generally wide angle lenses (shorter focal lengths) have deep depth of field, while telephoto focal lengths (longer) exhibit the shallower depth of field.
  • Distance - Distance does play a factor in this, in terms of where the actual focal plane is, with the depth of field placing an envelope around this where things tend to be in focus. Regardless of the depth of field - the focal plane (i.e., where the focus is defines actually what is in focus.
The links below have calculators, tables and in a couple of cases graphs, however - you need to supply the information for your particular situation of interest. The calculated information is for general cases. Macro is going to be a function of distance, with the shorter distances getting into the close focus situations. In terms of macro, you need to realize that with macro lenses magnification comes into play also.With an interest in Macro, you need some additional information. You can add in extension tubes or bellows (adding focal length for a lens), focal rail (controlling the distance to the object), etc.
thanks so much! appreciate the help.

09-30-2013, 12:05 PM   #5
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QuoteOriginally posted by interested_observer Quote
[*]Focal Length - Generally wide angle lenses (shorter focal lengths) have deep depth of field, while telephoto focal lengths (longer) exhibit the shallower depth of field.
Well, it isn't that dependent of focal length, it's mainly about magnification. At the same magnification things get really close except extremely wide lenses that you have to count in another aspect (can't remember the name of it). So at 1:1 macro distances it's almost the same, though compressing the background gives an illusion of deeper DOF.

Understanding Depth of Field in Photography
"If the subject occupies the same fraction of the image (constant magnification) for both a telephoto and a wide angle lens, the total depth of field is virtually* constant with focal length! This would of course require you to either get much closer with a wide angle lens or much further with a telephoto lens"
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