A depth of field calculator for working out exactly where your sharpness zone falls. Pick your sensor, enter the focal length, aperture, and subject distance, and you’ll see the near and far limits, the total depth of field, and the hyperfocal distance for that combination.
Uses the standard thin-lens approximations with a circle of confusion of 0.030 mm (full frame) scaled by crop factor. Real-world sharpness also depends on viewing size and print distance.
The math behind depth of field has a few moving parts — sensor size, focal length, aperture, and subject distance all factor in — so it’s not the kind of thing you can comfortably do in your head. The calculator handles it. What follows is a working photographer’s tour of when knowing those numbers actually matters in the field.
When depth of field actually matters
Landscape work and the hyperfocal distance
The hyperfocal distance is the closest focus point at which everything from half that distance to infinity falls within acceptable sharpness. Focus there and you maximize your depth of field for a given focal length and aperture.
For landscape work this is genuinely useful. If you’re shooting at 24mm and f/11 on a full-frame camera, the hyperfocal distance works out to about 1.77 m — meaning you can focus there and have everything from roughly 0.88 m to infinity acceptably sharp. Focus to infinity instead and you’ve thrown away a chunk of foreground sharpness for no benefit.
The catch is that “acceptably sharp” depends on assumptions about viewing distance and print size that don’t always hold. For pixel-peeping or very large prints, focus stacking is more reliable than relying on hyperfocal calculations. But as a quick field reference, the hyperfocal value is a solid starting point.
Portrait subject isolation
If you’re shooting a portrait at 85mm f/1.4 on full frame from 2 meters away, your total depth of field is about 4.5 cm. That’s why the eyes can be sharp while the ear is already softening. Knowing exactly how thin that slice is helps with focus accuracy decisions — whether to use eye AF, where to place the focus point manually, and whether you need to stop down a touch for a slightly more forgiving zone.
It’s also useful for matching looks across cameras. The same framing on Micro Four Thirds — using a 42.5mm lens at the same f/1.4 from the same 2 meters — gives you about 9.1 cm of depth of field. Roughly twice as deep as full frame at the same aperture and framing. Neither is wrong; they’re just different looks. The calculator makes that explicit instead of leaving it to feel.
Macro and close-up work
This is where depth of field gets unforgiving. At 1:1 macro distances, even f/16 might give you only a couple of millimeters of total sharpness. Knowing the actual number tells you whether a single-frame shot is feasible or whether you’ll need to focus stack.
One quirk worth flagging: at very high magnifications, the standard DOF formulas (which the calculator uses) start to lose accuracy because they’re built on a thin-lens approximation that breaks down at close focus distances. The numbers are still useful as a guide, but for serious macro work, checking sharpness on the back of the camera at the actual shooting distance is more reliable than trusting the math.
Group shots where you need enough DOF
The opposite problem from portraits. If you’ve got a row of people standing at slightly different distances from the camera, you need enough depth of field to keep all of them sharp.
A common scenario: 50mm at f/4 on full frame, group standing 3 meters away. Total DOF is about 87 cm. That’s enough for a single row but tight if you’ve got two rows of people standing close together. Bump to f/5.6 and you’ve got around 1.24 m of depth — more comfortable. The calculator tells you this directly instead of you having to find out at the shoot.
Architecture and interiors
Architectural and interior work usually wants everything sharp from the foreground to the back wall. Calculating the hyperfocal distance for your chosen focal length and aperture, and focusing roughly at that point, gets you most of the way there without overusing small apertures (which lose sharpness to diffraction).
Why sensor size affects depth of field
For the same framing of a subject, smaller sensors give you more depth of field at the same f-number. This is why phone cameras — with their tiny sensors — struggle to produce genuine background blur without computational tricks, and why medium format cameras can produce that distinctive shallow look at relatively modest apertures.
The math is straightforward but counterintuitive. Cropping the sensor doesn’t change DOF directly; what changes is the shooting setup needed to keep the framing consistent. If you switch from full frame to APS-C and want the same composition, you either step back, use a wider lens, or accept different framing. All three of those changes affect depth of field.
The shorthand “equivalent aperture” handles this neatly. A 50mm f/1.8 on Micro Four Thirds gives roughly the same depth of field as a 100mm f/3.6 on full frame, framed equivalently from the same distance. Same look, same DOF, different gear.1
A note on circle of confusion (and why DOF calculators disagree)
If you’ve used multiple DOF calculators, you’ve probably noticed they give slightly different numbers for the same setup. That’s because they use different values for the circle of confusion — the size of the largest blur spot that still reads as “sharp” to a typical viewer.
This calculator uses 0.030 mm for full frame and scales it by the crop factor for other formats — the convention most modern calculators use, in the same family as the classic Zeiss d/1500 rule of thumb. That works out to 0.019 mm for Canon APS-C, 0.020 mm for other APS-C, 0.015 mm for Micro Four Thirds, 0.011 mm for 1-inch sensors, and 0.038 mm for medium format (44 x 33).2
The practical takeaway: DOF numbers are a guide, not gospel. They assume a typical viewing distance and a typical print size. If you’re going to be looking at your image at 100% on a 5K display, your effective DOF is shallower than the calculator suggests. If you’re displaying it as a 6-inch print on a magazine page, it’s deeper. Use the numbers as a starting point and trust your eyes for the rest.
A few things worth knowing
The DOF formulas are based on a thin-lens approximation. Real lenses with complex optical designs — especially macro lenses, telephotos with floating elements, and lenses near the edges of their focus range — can deviate from the predictions. The calculator gets you within striking distance for typical shooting scenarios, but isn’t a substitute for actually checking sharpness at the shoot.
Diffraction starts eating into sharpness at small apertures, and the threshold is sensor-dependent. For full frame, expect noticeable diffraction softening past f/11 and significant loss past f/16. Smaller sensors hit the threshold sooner: Micro Four Thirds users typically don’t go past f/8 unless absolutely necessary.
Finally: the “sharpness” in a DOF calculation is acceptable sharpness for typical viewing, not critical sharpness. The point of true sharp focus is always the subject distance you focused at. Everything else is a gradient of progressively softer focus that crosses an arbitrary threshold defined by the circle of confusion.
Notes & References:
- Multiply the f-number by the crop factor to get the full-frame equivalent — so f/1.8 on a 2x-crop MFT sensor behaves like f/3.6 on full frame for DOF purposes. This is also covered in the crop factor calculator. [↩︎]
- The 0.030 mm figure traces back to assumptions about viewing an 8 x 10 print from around 25 cm with normal vision — roughly the sensor diagonal divided by 1500. Other conventions exist, including the stricter 1730 divisor (about 0.025 mm on full frame, which yields shallower calculated DOF), and some calculators use sensor-specific values worked out differently. [↩︎]
