ApertiaMake a distance sketch
Imagine two rows occupying distances from 3.5 m to 4.5 m. Write those distances down and choose an initial focus distance near the group, then run the calculator. Do not automatically place focus one third into the scene: the distribution changes with the settings and subject distance.
Keep the edge positions in mind. A person turned towards the centre may have a near eye outside the distance you first measured. Recheck after moving a row or changing the camera position.
Compare two realistic settings
As a planning example, a 50 mm lens at f/5.6 focused at 4 m with a 0.030 mm circle of confusion produces limits of roughly 3.2 m and 5.4 m. That geometric zone covers the example rows, but your required print size may justify a stricter criterion.
Compare another aperture without changing the other inputs. Then check the camera's exposure: a longer shutter time can let people blur even though they are inside the calculated zone.
Check the photograph while the group is still there
Review faces near the front, back and edges at a useful magnification. Look for movement as well as missed focus. If someone changes position, refocus and check again; the earlier calculation described the earlier arrangement.
- Keep the camera position stable during the sequence.
- Tell the group when the exposure is happening.
- Leave breathing room for normal posture changes.
- Use your actual sensor and viewing criterion in the calculator.