I. CAMERA FEATURESAND OPERATION 7
The EOS-1D and EOS-1Dshad the fastest AF systems available among EOSSLRs when
theywere introduced, but the EOS-1D Mark II now has the most powerful AF system of
anyEOS camera released to date (2004). The EOS-1D Mark II was the firstCanon camera
to feature two dedicated CPUsfor AF: one for detection and calculation, and another to
controllens drive. EOS-1 class cameras prior to the 1D Mark II used a single dedicated
CPU for allAF operations.
AllEOS-1 class digital SLRs feature RISC (Reduced Instruction SetComputing)
processorsso that multiple operations can be performed simultaneously. The extra
speed created through thismethod has made it possible to increase the power and
sophistication ofthe algorithms employed for predictive AF. Using an EF 300mm f/2.8L
ISUSM lens and a fully charged battery pack, the original EOS-1 with Power Drive
Booster PB-E1 could tracka subject moving at 300 kph/186 mph as close as 26
meters/85 ft. Using an EF300mm f/2.8L IS USM lens and a fully charged battery pack,
an EOS-1D MarkII or EOS-1Ds Mark II can track a subject moving at300 kph/186 mph
asclose as 20 meters/66 ft.
10 feet
6 feet
250mph 185 12562 303mph 6
20 feet
33 feet
66 feet
98 feet
400km/h30020010050105km/h
1m
2m
3m
6m
10m
20m
30m
Predictive AI Servo AF Performance
How close can the camera track a moving subject with an EF300mm f/2.8L IS Lens
Subject Speed
EOS-1: 5 fps (with Power Drive Booster E1) EOS-1D Mark II: 8.5 fps
Subject Distance
The Evolution ofAF Speed
& Predictive AFControl