Canon EOS 20D

Canon EOS 20D
Type	Single-lens reflex
Sensor	22.5 mm × 15.0 mm CMOS
Maximum resolution	3,520 × 2,344 (8.25 megapixels)
Lens type	Interchangeable (EF EF-S)
Shutter	Vertical travel, focal-plane shutter, all speeds electronically controlled
Shutter speed range	1/8,000 to 30 s, bulb
Exposure metering	TTL full aperture, 35 area evaluative, partial, center-weighted
Exposure modes	Full auto, programmed, shutter-priority, aperture priority, manual
Metering modes	Evaluative, Partial, C/Wgt Average
Focus areas	9 autofocus points
Focus modes	One-shot, AI servo, AI Focus, Manual
Continuous shooting	5.0 frame/s, up to 23 frames (9 in RAW)
Viewfinder	Optical, pentaprism
ASA/ISO range	100–1600 in 1 EV steps, 3200 in extended mode
Flash	Auto pop-up E-TTL II (retractable)
Flash bracketing	none
Focus bracketing	none
Custom WB	7 presets, Auto and custom
WB bracketing	±3 stops, blue-amber or magenta-green bias
Rear LCD monitor	1.8 in (46 mm), 118,000 pixels
Storage	CompactFlash (CF) (Type I or Type II) and Microdrive (MD) / max 8GB (The camera can format up to 8GB, but can use larger cards.[citation needed])
Battery	Main battery Li-Ion BP-511A rechargeable battery pack; internal memory battery CR2016 supports clock, frame counter
Dimensions	144 x 105.5 x 71.5 mm
Weight	685 g (body only)
Optional battery packs	Li-Ion BP-511A, BP-511, BP-512, BP-514AC and optional DC coupler.
Made In	Japan
Retail info

The Canon EOS 20D is an 8.2-megapixel semi-professional digital single-lens reflex camera, initially announced on August 19, 2004 at a recommended retail price of US$1,499. It is the successor of the EOS 10D, and was succeeded by the EOS 30D in August 2006. It accepts EF and EF-S lenses and uses an APS-C sized image sensor.

Improvements

The 20D features a new sensor and more megapixels (8.2 megapixels instead of 6.3) and retains the 1.6 crop factor. It supports USB 2.0. The 20D has a larger buffer and can shoot more frames per second. It also uses the E-TTL II flash metering system and uses the DIGIC II image processor.

The EOS 20D (with appropriate firmware updates) can also accept the Canon Wireless File Transmitter WFT-E1/E1A for fast file transfer to a remote file server, either through an ethernet cable or a Wi-Fi network.

Features

The 20D is the first Canon prosumer camera to use the EF-S lens mount; the first Canon EOS camera to use the mount was the 300D (the Digital Rebel in North America).

EOS 20Da

M42, The Orion Nebula photographed with a Canon 20Da and a 76mm telescope

Canon released the EOS 20Da on February 14, 2005 in Japan. It is a variant of the 20D designed for astrophotography. On June 1, 2005 Canon announced that the 20Da would be made available worldwide.^[1]

The main differences between the 20Da and 20D are the replacement of the "hot mirror" infra-red (IR) filter which covers the CMOS sensor on the 20D and live view mode^[2].

In conventional photography, the IR filter is used to make the spectral response of the CMOS sensor more like that of the human eye. In this way, the pictures gathered by the sensor more closely resemble the world as we see it. In astrophotography, many objects of interest emit strongly in the red H-α line, which is heavily attenuated by the IR filter on the 20D. The IR filter of the 20Da passes 2.5 times more light at around this 656 nm wavelength as the filter of the 20D, allowing more fine detail to be revealed in long exposures of emission nebulae. A separate IR filter must be attached to the lens in order to use the 20Da to capture images similar to those seen by the human eye.

It is extremely difficult to focus an extremely dim image with a reflex viewfinder; locking the mirror up and opening the shutter (live view) was introduced in the 20Da to address this issue. When used the camera provides a live image of the center of the field of view to allow focusing on a bright star. Live view for this application requires a lens which supports fully mechanical focus in manual mode, and is not suitable for normal daytime use.

There were reports that the camera did not perform up to expectations, and had problems with image noise, but was capable of outstanding images^{[3][unreliable source?]}.

The EOS 20Da was discontinued when the 30D was introduced in 2006^[4]. Canon has produced no similar model for astrophotography since, though many astrophotographers commonly make similar aftermarket modifications to later Canon models to fill the same role.

Firmware

The latest firmware available for the 20D (and believed to be the final update) is version 2.0.3, made available August 23, 2005, which improves the communication reliability with some CF cards and other minor changes.

Gallery

20Da

References

External links

Wikimedia Commons has media related to: Canon EOS 20D

• Canon EOS 20D Specifications