Canon 20Da Review
The low-pass filter in front of the 8.2-megapixel CMOS sensor of the EOS 20Da, for example, captures a spectral range 2.5 times larger than that of the EOS 20D due to a different coating. The EOS 20Da is particularly sensitive to light with a wavelength of 656 nm (known to physicists and astronomers as the hydrogen-alpha line or Hα wavelength) and can thus image various astronomical phenomena such as diffuse reddish star clusters more sharply and with higher contrast. But since the EOS 20Da also almost penetrates into the infrared range, it is recommended to screw an infrared blocking filter onto the lens when photographing everyday subjects such as people, rather than stars.
The EOS 20Da has a live image or image preview function (with 5x and 10x magnifying glasses) on the 1.8″ LCD colour screen on the rear of the camera to make it easier to determine the correct image detail and focus when taking astronomical pictures. Contrary to what is written on dpreview.com, this is not achieved by a partially permeable mirror. A part of the mirror actually lets light through, but this is also the case with the EOS 20D (and all other SLR cameras with TTL exposure metering), because this way a part of the light is redirected to the exposure measuring cell in the viewfinder during the exposure process when the mirror is folded up. In any case, the EOS 20Da does not have a rigid semi-transparent mirror such as the Olympus E-10/20 or the 35mm cousin EOS RT. For example, the EOS 20Da requires the mirror to be folded up in order to use the live image function. In addition, of course, the shutter must also be opened for the preview time, which is achieved by calling up the BULB long-time exposure function. However, the preview does not take longer than 30 seconds because the CMOS image converter heats up due to its permanent readout and this results in a stronger image noise. Due to the relatively long opening of the shutter, the live image function is also not suitable for shooting in bright light. The live image function can also be used when connecting the camera via the video output with a TV or similar.
New firmware available for Canon EOS 20D/a
The firmware with version 2.0.3 for the Canon EOS 20D and its sister model EOS 20Da ensures that the camera transfers the colour temperature information correctly back to the Speedlite 430EX system flash unit and that data exchange with the CompactFlash memory card is even more reliable. The EOS 350D also benefits from better communication with the memory card when “fed” with the new firmware number 1.0.3. In addition, a problem with the picture reproduction (camera does not stop scrolling under certain circumstances) and with the remote release with the infrared remote control RC-1 (camera refuses recording under certain circumstances) is solved.
As with so many digital cameras, the update procedure does not require any special technical knowledge. All you need to do is go to the page where you will find all the information you need to update. After you have explicitly read the update instructions and the license agreement by clicking on the confirmation button, you will be redirected to the actual download page. There you download the appropriate update file for your operating system and decompress it by double-clicking on the program icon. This creates the actual firmware file (with the file names 20d00203.fir for the EOS 20D, 20da00203.fir for the EOS 20Da and e3kr2103.fir for the EOS 350D), which is copied either via an external card drive or via the camera-computer connection via USB into the main directory of a CompactFlash memory card. After inserting the memory card, turn on the camera and go to the Setup menu to find the appropriate item to update the firmware. The update starts as soon as the user gives his okay.
As always, it should be pointed out that the update is carried out by the user on his own responsibility – also in compliance with the usual precautions (update only in mains operation or with fully charged battery). Canon recommends that you also update without the lens attached. An interruption of the power supply, e.g. due to an exhausted battery, can, in the worst case, lead to a total failure of the camera, where only the customer service of the manufacturer remains as the last hope for a quick camera recovery. If the whole thing is too tricky for you and you don’t dare to carry out this – not entirely risk-free – operation yourself, you should only change the firmware when you really need it or have the update carried out by a dealer or Canon service centre.