Tutorial What Is Depth of Field?

Garry Edwards

Garry Edwards

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Garry Edwards
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Garry Edwards submitted a new resource:

What Is Depth of Field? - dof is simply the range of distances in a photograph that appear to be acceptably sharp

Explaining the jargon
I try to avoid jargon, but it does help if we all understand what it means . . .

  • F. The focal length of the lens, so F100 is a 100mm lens
    f/ If you use a 100mm lens and the aperture opening is 50mm wide, the calculation is 100 / 2, written as f/2
  • Depth of Field (DOF): the range of distances in a photograph that appear acceptably sharp, extending from the nearest to the furthest point that appears sharp.
  • Depth of focus...
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Read more about this resource...
 
Seems the LF f16 and f5.6 examples although no scientific seem the wrong way round? Id expect 5.6 in LF to be much shallower and blurrier than f16
 
thedistrictline said:
Seems the LF f16 and f5.6 examples although no scientific seem the wrong way round? Id expect 5.6 in LF to be much shallower and blurrier than f16
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Yes, looks like it, but the way I went around that image creation should have prevented it.
I did them in that order - Create a side by side image of a yellow tape measure etc, measure extended from zero to 150cm. Left image 5"x4", F210, f/5/6. centre image Nikon D3, F80, f/5.6 etc, followed by the other prompts at f/16 and finally at f/128, with diffraction limitation shown at f/128 and with 100% crops appended.
I have a paid subscription, which they claim to be far more detailed and accurate than the free version.

But, there are obviously still limitations with AI image generation, which I why I voiced my doubts about its accuracy, experience tells me that it's wrong but it's what it is - health is stopping me from actually doing it myself.

As a rider, I don't think that I've ever actually shot a 5x4 at f/5.6. Some lenses don't even open that wide and when they do, they're for ease of focussing.
 
Diffraction seems a very polarizing topic akin to ISO I find, some won't even think about shooting asp-c past f11, I'm of the mind unless your comparing side by side I'm not sure you'd be able to tell although my tolerances are much less than others
 
I agree with you, I never hesitate to stop down a bit further than is safe in terms of diffraction limitation if needed in order to get adequate dof.

As I pointed out in the article, it's a tradeoff. We need to understand the physics, but it's a bad idea to become obsessed with them.
 
Garry Edwards reply is correct.
Also there is also what I call "depth of photograph "which is slightly different.
Example
M2240009.JPG

Here by adding a small bush to the bottom of the photo throws the house (Scotney Castle in Kent) into the background. Without it a picture of a lot of water does not create the same effect. This can be done by overhanging branches which I often use as well
 
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