Depth of Field Calculator
Find the near and far focus limits for a given aperture, focal length, and subject distance.
Results
- Near limit
- 2.73 m
- Far limit
- 3.33 m
- Total depth of field
- 60.0 cm
- Hyperfocal distance
- 29.81 m
The closest point to the camera that will still look acceptably sharp.
The farthest point from the camera that will still look acceptably sharp.
The total span, from near limit to far limit, that will be in acceptable focus.
The focus distance that would maximize depth of field for this focal length and aperture.
How it works
Depth of field is the zone in front of and behind your focus point that still looks acceptably sharp. Only one plane is ever truly in focus; everything else is blurred by some amount, and depth of field is simply the range where that blur is small enough to go unnoticed.
That threshold is the circle of confusion. This calculator uses the standard convention of the sensor diagonal divided by roughly 1500, which is the blur spot that disappears at normal viewing distance on a standard-sized print. That is why a smaller sensor gets a smaller circle of confusion, and why depth of field figures always come attached to an assumed print size.
Three things move depth of field: aperture, focal length, and subject distance. Distance is by far the strongest of the three, because depth of field grows roughly with the square of the focus distance. Stopping down from f/2.8 to f/8 buys you a bit under two stops of extra depth, but backing up to twice the distance roughly quadruples it.
The formula
H = f² / (N × c) + f, near = H·s / (H + (s − f)), far = H·s / (H − (s − f))
H is the hyperfocal distance, f the focal length, N the f-number, c the circle of confusion, and s the focus distance measured from the lens's front principal plane. When s reaches H the far limit becomes infinity.
Frequently asked questions
- Does a smaller sensor really give more depth of field?
- At the same focal length and aperture, yes, but that comparison is misleading because the smaller sensor also frames a narrower view. Match the framing by using a shorter lens on the smaller sensor and it gains depth of field by roughly the crop factor, which is where the equivalent aperture idea comes from.
- Why does the far limit say infinity?
- Once your focus distance reaches the hyperfocal distance, the far limit extends forever. Anything from roughly half the hyperfocal distance to the horizon falls inside the acceptable blur threshold.
- Is depth of field really split one-third in front and two-thirds behind?
- Only at moderate distances. The split approaches an even 50/50 at close focus and stretches far beyond two-thirds behind as you approach the hyperfocal distance. The calculator gives the actual near and far limits rather than relying on the rule of thumb.
- Why does the calculator refuse very close focus distances?
- Closer than twice the focal length you are past 1:1 magnification, where the thin-lens model this calculator uses stops describing reality and starts returning negative depths. For work that close, use the magnification calculator instead.
Read more about this
- Crop factor and equivalence, without the argumentsEveryone agrees crop factor multiplies focal length. The argument starts one line later, at aperture, and it is mostly people answering different questions.
- Hyperfocal focusing in practiceThe technique works. The way it is usually taught puts infinity right on the edge of acceptable, which is the one place you do not want it.
- Why your depth of field calculator disagrees with your photographsThe calculator said the whole scene was sharp. At 100% on screen, half of it clearly is not. Both things are true, and the reason is a number nobody mentions.
- The diffraction limit is not a cliffDiffraction gets talked about as a wall you hit at f/11. It is closer to a slope you have been walking down since f/4.