Depth of Field Calculator

How depth of field works

Depth of field is the range of distances in a scene that appear acceptably sharp in a photograph. Objects closer or further than your focus point are always out of focus to some degree. DOF describes how wide that acceptable zone is.

Three variables control depth of field:

• Focal length. Longer focal lengths produce shallower depth of field at the same aperture and subject distance.
• Aperture. Wider apertures (lower f-numbers) produce shallower depth of field.
• Subject distance. Closer subjects produce shallower depth of field. Moving further from your subject increases DOF significantly.

Circle of confusion

The calculator uses the circle of confusion (CoC) value for each sensor size. A point of light in a scene that is not at the exact focus distance gets projected onto the sensor as a small disc rather than a point. If that disc is small enough, it still looks sharp to the human eye. The CoC is the maximum diameter of that disc that still looks acceptably sharp.

Smaller sensors use smaller CoC values because their images are enlarged more to reach the same display size, which makes blur more visible. M43 uses a CoC of 0.015mm, APS-C 0.020mm, and full frame 0.030mm.

Hyperfocal distance

Hyperfocal distance is the closest focus distance at which objects from half that distance to infinity all fall within the acceptable sharpness range. When you focus at the hyperfocal distance, you maximise the depth of field for a given focal length, aperture, and sensor.

Hyperfocal distance is useful for landscape and street photography where you want everything sharp without hunting for a specific subject. Focus at the hyperfocal distance and everything from roughly half that distance to infinity is sharp.

The hyperfocal distance gets longer as focal length increases and gets shorter as you stop down. A 12mm lens at f/8 on M43 has a very short hyperfocal distance, which is why wide-angle lenses stopped down appear to have infinite depth of field in practice.

M43 vs full frame depth of field

At the same f-number and the same subject distance, M43 produces more depth of field than full frame because of the smaller sensor and tighter CoC tolerance. To get the same depth of field on M43 as you would on full frame, you need to open up by 2 stops.

This is often cited as a disadvantage for portrait work (harder to get that shallow background blur), but it is an advantage for macro, product, and landscape work where you want more of the scene in focus without stopping down to diffraction-limited apertures.