Viewfinder / Auto-Focus

The EOS-1D's viewfinder is similar to that found on the EOS-1V except for: additional status information, differently positioned dioptre adjustment (on the 1V the eyepiece must be removed to adjust), eyepiece now protrudes 20 mm (0.8 in) from the rear of the camera (this helps to keep your nose away from the LCD screen) and that the actual view of the focus screen is cropped to match the sensor's smaller proportions. Canon state frame coverage as 100%, we measured it as exactly 98%. The viewfinder view is very large, noticeably larger, clearer and brighter than the EOS-D30.

The diagram on the right below shows the AF ellipse and the 45 focus points, the center spot as well as meter indicators (active points will glow red once AF is locked), buffer space indicator (88 JPEG) and camera status readout (horizontally along the bottom). The buffer space indicator automatically adjusts itself depending on the selected ISO sensitivity, for example when empty at ISO 200 it shows 21 JPEG images, at ISO 800 it shows 14 JPEG images (this is a camera estimate).

In automatic AF point selection mode the camera will highlight (glowing red) the AF points which were used to measure AF distance. On the right side of the viewfinder is the eyepiece shutter lever (not visible above), this allows you to blackout the viewfinder eyepiece to prevent stray light entering the camera during long or remotely triggered exposures.

AF CMOS sensor	Cross-type sensors (horizontal and vertical sensitive) only with lenses with max. aperture of F2.8 or faster

The EOS-1D uses the same 45-point area AF CMOS sensor used in the EOS-1V, it measures 15 x 8 mm and is located just below the semitransparent mirror and receives the exact same image you see through the viewfinder.

All AF points are sensitive to horizontal detail, however for a lens with a maximum aperture of F2.8 or faster lens a vertical row of 7 points (as indicated in red in the diagram above, right) become sensitive to both horizontal and vertical detail, and the manual notes, are three times more sensitive than the normal horizontal sensors. Some other L lenses with maximum apertures of F4 or brighter make use of the center cross-type AF point.

Having 45 focusing points isn't just about being able to choose your focus area within the image it also means that focus tracking (AI Servo) can be much more effective (as the subject is more likely to be picked up by at least one AF point).

AF point selection modes

Automatic selection - in this mode the camera will automatically select (and indicates) the AF point(s) which have been used to calculate the focus distance. C.Fn 10 allows you to change or disable the method of focus point indication.	45 AF Point Manual selection - in this mode the main dial (top of camera) moves the AF point horizontally, sub command dial (rear) moves AF point vertically.
11 AF Point Manual selection - in this mode the main dial (top of camera) moves the AF point horizontally, sub command dial (rear) moves AF point vertically. C.Fn 13 - 1 or 2	9 AF Point Manual selection - same procedure as described in the other modes, the AF Assist button and sub command dial can be used to quickly select a peripheral point. C.Fn 13 - 3

Registered AF point

The EOS-1D has also has a 'registered AF point' feature, this allows you to store the position of a most used AF point (such as the center point) and have it activate when the AF Assist and AF Point buttons are pressed, this is extremely useful for quickly switching back to a default AF point.

Diagrams reproduced from the EOS-1D manual by permission.

Metering system / zones

Just like the EOS-1V the 1D has a 21-zone evaluative metering system. This provides several metering modes: evaluative, partial, spot, center-weighted average, AF point-linked spot and multi-spot metering (plus flash E-TTL and TTL). The diagram on the left, above shows how these areas equate to the portions of the viewfinder view and AF points, in AF point-linked spot metering mode one meter zone serves several AF points.

21 metering zones overlaid on the viewfinder view image	21 zone meter sensor

Lens mount / Mirror / Shutter

The EOS-1D has the EF lens mount (identical to the EOS-1V / D30) and therefore supports all Canon EF type lenses. Remember any lens mounted on the EOS-1D will have an effective focal length (or more accurately cropped field of view) 1.3x of that marked on the lens. Eg. a 28 mm lens provides a field of view equivalent to 36.4 mm on the EOS-1D. In this image you can also see the depth-of-field preview button on the side of the lens mount.

The mirror mechanism is the same as found on the EOS-1V, that means it also features the same Active Mirror Control system which uses a 'shock absorber' to soak up the bounce produced when the mirror flips back down to the normal position. This system means that 'mirror blackout' (the amount of time the viewfinder view is black) is just 87 ms. This high speed mirror system is of course absolutely essential to achieve the eight frames per second shooting speed.

The other item required to maintain the eight frames per second continuous shooting speed is the shutter. The EOS-1D's shutter is similar to the one found on the 1V. It uses a special rotary magnet which never actually contacts the shutter blades, the blades themselves are made from carbon fiber and super-duralumin. Because of its design the shutter requires no power in the 'open' position (for long Bulb exposures for example).

White balance sensor

Just like the EOS-D2000 (but unlike the D30 or other recent digital SLR's) the EOS-1D has an external white balance sensor mounted on the top right corner of the camera (from the front). This is used to provide 'additional information' to the camera's white balance system in combination with any reading measured by the main CCD. Canon have coined the name 'hybrid automatic white balance system'.