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Matthew · 07-02-2009, 07:59 PM

I have a problem with the Online Depth of Field Calculator web site.
If you change between sensor sizes, it changes the depth of field figures.
Surely depth of field stays constant for a given lens at a given aperture and focal distance. After all, if you change sensor size you are only cropping (or uncropping the image).
Now I understand that if I want to shoot the same subject at the same size with a different sensor size, I will need to change my camera-subject distance (and thus focusing distance) or change my focal length and this will change my depth of field if using the same aperture. However this is not what the Online Depth of Field Calculator is claiming to do.
Any thoughts?
Have I missed some important point?

Do I not understand what the term "depth of field" means?

07-02-2009, 07:59 PM	#8
Matthew Member Location: Australia Gallery Photos: 7 Posts: 62	Does depth of field change depending on sensor size? I have a problem with the Online Depth of Field Calculator web site. *If you change between sensor sizes, it changes the depth of field* figures.** Surely depth of field stays constant for a given lens at a given aperture and focal distance. After all, if you change sensor size you are only cropping (or uncropping the image). Now I understand that if I want to shoot the same subject at the same size with a different sensor size, I will need to change my camera-subject distance (and thus focusing distance) or change my focal length and this will change my depth of field if using the same aperture. However this is not what the Online Depth of Field Calculator is claiming to do. Any thoughts? Have I missed some important point? Do I not understand what the term "depth of field" means?