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Auto-focus on most cameras (those that use phase / contrast detecton AF, at least) doesn't emit anything, unless you mean emissions from the circuitry used to c
by yangyang 17y ago
Auto-focus on most cameras (those that use phase / contrast detecton AF, at least) doesn't emit anything, unless you mean emissions from the circuitry used to control it. Some cameras have a AF assist light for helping the AF in low light, but that won't come on in daylight.
You do need to focus at distance with long, fast lenses.
- jrg 17y agoAt a distance you'd stop-down the lens aperture, stick it in manual focus, and set it to somewhere around infinity. (and big, fancy yachts are always moored somewhere sunny, off the coast. So no problem there.)
- yangyang 17y agoDepends how long a lens you're using. You'd need a pretty fast shutter speed at 600mm+.