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Peering inside Nikon's D3 and D300

Glimpse the innards of the Nikon D3 and D300 digital SLRs without voiding your warranty.

Update: I fixed a math error in the shutter description.

Nikon's D3 and D300 SLR (single-lens reflex) cameras, announced Wednesday, are complicated and expensive beasts, so few people outside a repair center or Canon's competitive intelligence unit are going to be cracking them open.

Happily, Nikon has provided a number of views into its new $5,000 D3 and $1,800 D300 cameras. Forthwith, a tour of what I find most notable.

Full-frame sensor


The single biggest change in the D3 from earlier pro models such as the D2HS is the "full-frame" sensor, which measures 36x23.9 mm, just a hair shorter than a full frame of 35mm film measuring 36.24mm.

Branded processor


Nikon has chosen to brand its image processor, and the D3 and D300 both use the Expeed. Here it's shown nested in the D3's computing board. The Expeed joins other branded engines such as Canon's Digic, Panasonic's Venus Engine, Olympus' TruePic, Pentax's Prime and Sony's Bionz.

High-def output


The D3, shown here, and D300 both have HDMI output so photos can be viewed directly on high-definition TV. Most cameras today only can display on standard-definition TV signals.

D3's skeleton


The D3 and D300 have magnesium alloy chassis. Shown here is the D3's.

Autofocus operations


The D300's Multi-CAM 3500DX autofocus system, shown above, and the D3's Multi-CAM 3500FX cousin both incorporate 15 cross-type sensors that can detect vertical or horizontal contrast in images. The autofocus system also works in conjunction with the exposure system to estimate better which autofocus points should be used.

Metering sensor


The D3 and D300 both use the same 1,005-segment metering sensor. It recognizes colors and light patterns to help the camera guess the scene type and set exposure accordingly.

Shutter: start clicking


The D3's shutter, shown above, is rated at 300,000 cycles, and the D300's is rated to 150,000. High ratings are handy with digital, where having an itchy trigger finger just fills up a flash memory card instead of costing a lot in film and development expenses. At the D3's top speed of 9 frames per second, if the camera didn't have other limits, you'd have to hold the shutter release button down for more than 9 hours before hitting the shutter's duty cycle.

D3 Pentaprism


The D3 has a big pentaprism, which directs light that's traveled through the lens and bounced off the reflex mirror toward the viewfinder. The viewfinder itself shows virtually all of what the sensor sees at a magnification of 0.7.

Shooting faster with the D300


The MB-D10 battery pack for the D300 extends shooting life and can goose its shooting rate from the regular 6.5 frames per second up to 8.