Canon 40D - EOS 40D DSLR, Руководство по обслуживанию

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Technical Information
2
４）Electronic 1st-curtain shutter for Live View silent shooting
With Live View image displayed, the camera can seamlessly shift to slit exposures with
the electronic 1st-curtain shutter. It enables silent shooting which is not possible with a
mechanical 1st-curtain shutter. This electronic 1st-curtain shutter uses a unique high-speed
scanning and electronic reset system which accurately mimics the EOS 40D's high-speed
mechanical shutter operation. It synchronizes with the mechanical 2nd-curtain shutter to
obtain a slit exposure.
＊ With CMOS, it is difficult to have an electronic 2nd-curtain shutter. Therefore, only the 1st-curtain shutter is
electronic.
５）Power saving
To minimize the higher power consumption
required by the high-speed signal reading, the
output amp's power consumption has been kept to
an absolute minimum. Also, like the EOS DIGITAL
REBEL XTi/400D DIGITAL, to save power during long
exposures, power to the output amp is turned off and
the standard current driving the circuit is also cut off.
During Live View shooting, the power distribution
for the signal-reading operation is optimized as with
the EOS-1D Mark III. Such measures enable more
minute power-saving control.
６）Infrared, low-pass filter
The basic construction and performance of the
infrared, low-pass filter are the same as the EOS
DIGITAL REBEL XTi/400D DIGITAL's. (Fig. 002)
1.2 Image-recording and processing
Compared with the EOS 30D, the EOS 40D's image quality is much improved as follows,
thanks to the 10.10-megapixel CMOS sensor, DIGIC III imaging engine (single), etc.
●High image quality factors with the EOS 40D
1. Higher resolution with approx. 10.10 megapixels (CMOS sensor)
2. 14-bit signal processing for higher image quality (DIGIC III)
3. Noise reduction of high ISO shots (DIGIC III, C.Fn II-2)
4. Highlight tone priority (C.Fn II-3)
＊ For 2, see "Technical Information." For 3 and 4, see EOS-1D Mark III "Service Manual."
4. Low-pass filter -2
(Separates image
in vertical direction)
1. Low-pass filter -1
(Separates image
in horizontal direction)
2. Phaser layer
(Converts linear polarized
light into circular polarized light)
CMOS
sensor
Dichroic mirror
(Reflects infrared rays)
3. Infrared-absorbing glass
Fig. 002 Infrared, low-pass filter construction