Thread: 405 to 625
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Old 17th Jan 2017, 10:04 pm   #15
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Default Re: 405 to 625

I could have also mentioned that if the camera's video out and the image has gone a bit soft looking, at least its easily possible to sharpen it up a bit with a simple & cheap video accessory box with an aperture correction (high frequency) control before it is recorded for the first dub. The process might work better with a 1970's vintage B&W video camera based on a vidicon tube or similar because the image lag provides some flicker filtering, rather than a new digital camera, but I'm not 100% sure about this because the only cameras I have tried for this purpose in the past were tube based.

Also on the H resolution issue where the picture elements are touching vertically, this is discussed and calculated on page 266 Practical Television 1955 November: The corresponding bandwidth is 2.4MHz. This is still a reasonably crisp image on a small sized raster. And in practice, due to the focused spot size in the crt, a suitable tube/monitor could be a 5 or 6" tube. So a typical small B&W industrial monitor, modified to 405 lines could be used and the CRT focus just fractionally off until the lines just touch, if they were not touching already.That monitor could be built into a housing with the camera to make a fairly compact 405-625 converter unit.

Last edited by Argus25; 17th Jan 2017 at 10:21 pm.
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