what f stop gives most dof?

A

alexsmith

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Yes
This should be an easy question but for some reason I'm getting stumped:thinking:
If I am using this lens in the opposite way to normal and I'd like (deep?) depth of field..ie more distance in focus. This is the lens
70-300mm f/4-5.6
My thinking is , use the 70mm end and the biggest f no. possible. But is there anything to be gained by going over f11 even going to f22? I have played around but there are so many variables. I guess I'm better being further away too..
thanks alex
 
DoF is determined by image size (magnification) and f/number.

The smaller the image size (shorter focal length, greater shooting distance) the more DoF. If you increase focal length, but also move back so that image size remains constant, DoF remains the same.

The higher the f/number, more DoF. But be aware that at higher f/numbers, say f/16 and f/22, diffraction reduces ultimate sharpness, regardless of the quality of the lens.

Check it out on the DoF calculator here www.dofmaster.com
 
HoppyUK said:
DoF is determined by image size (magnification) and f/number.

The smaller the image size (shorter focal length, greater shooting distance) the more DoF. If you increase focal length, but also move back so that image size remains constant, DoF remains the same.

The higher the f/number, more DoF. But be aware that at higher f/numbers, say f/16 and f/22, diffraction reduces ultimate sharpness, regardless of the quality of the lens.

Check it out on the DoF calculator here www.dofmaster.com
Click to expand...


Thanks Hoppy that was exactly what I was looking for and now I know the answer to what distance I need to be. Ta
al
 
I think it's worth thinking about how much DoF will fit into the scene. For example if your scene is Xm deep you don't need DoF from 0.5m to infinity.
 
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