Canon EOS D60, Руководство по обслуживанию

Страница: 59 / 211

Part 2: Technical Information
2-6
1.3 AF system
1) Configuration of focusing optics
It is the same as the EOS D30.
2) High-speed AF and focusing computation
(1) Brightness range for AF
With improved maximum accumulation time for the AF and improved AF
algorithm, AF performance limit in low light has been improved by 1.5 stops (EV
2 to EV 0.5).
(2) AF speed, AF point automatic selection algorithm, and predictive AF control
These are all the same as the EOS D30.
3) AF-assist light
As with the EOS D30, the EOS D60 has a built-in krypton lamp for the AF-
assist light. The AF-assist light is linked to the three AF points.
The AF-assist light turns on automatically when the ambient light level is EV 4
or lower or when the AF has difficulty achieving focus. With the EOS D30, the AF-
assist light can light up to three consecutive times. With the EOS D60, it can light
up to six consecutive times (current point of focus
→
near point
→
far point: twice
each). This improves the chances of obtaining accurate focus in low light. The AF-
assist light's effective range is about 3.8 m at the viewfinder's center, the same as
the EOS D30's AF-assist light.
When an EX-series Speedlite is used with the camera, the AF-assist light is
emitted in the same way as with the EOS D30. With the 550EX and 420EX, AF-
assist is emitted by the external Speedlite. With the 220EX and 380EX, the
external Speedlite's AF-assist beam is emitted only when the center AF point has
been selected. If an off-center AF point has been selected, the camera's AF-assist
light will be emitted instead.
With C.Fn-5 (AF-assist/flash), you can now disable the camera's built-in AF-
assist light or the Speedlite's AF-assist beam.
Fig. 2-6 Cross section at center.