Infinity matters.
The quietest yet most decisive setting in photography: a sharp focus on infinity.
Most lenses carry an infinity (∞) mark, and turning the ring there is supposed to give the sharpest focus. Unfortunately most lenses leave the factory uncalibrated for this setting — trusting the mark will mislead you.
Finding true infinity.
Find your infinity focus through test shots. Try the focus ring at different positions near the mark, and note for yourself on the lens which number focuses sharpest. On modern cameras live view makes this easier: zoom into the screen and see the detail clearly.
Why does it matter so much?
If the infinity focus is wrong, the stars, the northern lights and every distant object come out blurred — and at the end of the night you're left with frames beyond saving. ×Corrected · 2024·mirrorless bodiesOn a DSLR, set it right once and trust it through the night; but after moving to a mirrorless body, quickly re-verifying after each lens change is a good habit.
+Added · November 2024·Focus peakingMy new body has focus peaking: in manual focus, the edges that are sharp glow with coloured pixels. The wider the lens, the narrower the area where peaking appears — it became my fastest way to calibrate infinity. On a tripod, zoom in near 10× and adjust slowly until a bright star becomes a point.- +Focus peaking note · mirrorless switch
- ×Re-verify after a lens change
- ○Original · book edition