29-11-2020, 11:22 AM
As I understand it, the early Emitron or Iconoscope camera tubes used a mosaic of caesium granules to transform the optical image into electronic form. There must have been a limited number of these granules and this would have set the maximum 'pixel count' of the image.
Is it known if this ever reduced the resolution below that required for a perfect 405-line picture?
Other limiting factors would have been the limited depth of focus; a result of the 'fast' lenses necessitated by low camera sensitivity, and subtle picture distortions remaining after the application of 'tilt' and 'bend' correction. At the receiver end, the grade of the phosphor on the display tube might have had an effect. And of course EHT values were low and presumably with it - the ultimate sharpness of the beam.
One is struck by the resulting slightly ghostly quality of the earliest television pictures as captured by photography, like those seen in 'Television and Short Wave World'. This is actually quite attractive and 'atmospheric'.
Steve
Is it known if this ever reduced the resolution below that required for a perfect 405-line picture?
Other limiting factors would have been the limited depth of focus; a result of the 'fast' lenses necessitated by low camera sensitivity, and subtle picture distortions remaining after the application of 'tilt' and 'bend' correction. At the receiver end, the grade of the phosphor on the display tube might have had an effect. And of course EHT values were low and presumably with it - the ultimate sharpness of the beam.
One is struck by the resulting slightly ghostly quality of the earliest television pictures as captured by photography, like those seen in 'Television and Short Wave World'. This is actually quite attractive and 'atmospheric'.
Steve
