Shading Console
 

In most of the books that I've seen dealing with television production pre-1950, they mention a shading console and a shading console operator in the production booth, and their purpose was to compensate for non-uniform image brightness problems like flaring.
Is there something like this still in use today, and if not, when did it die out?

The live shading console was needed only for iconoscope cameras. Other types of pickup tubes had shading problems that needed compensation also, but it did not change with scene content like an iconoscope did.

Modern high-end tube cameras (Plumbicons, etc.) eventually would have elaborate automated shading correction based on a test slide built into the studio lens. The shading would be dual level, compensating both lowlights and highlights (black level and gain). There would also be automatic registration of the red, green and blue images, and live dynamic correction based on a look-up table for lens distortions both geometric and chromatic as the zoom and focus were changed.

OK. But I just have a couple more questions. Could you explain to me what you mean by "the studio lens"?
Also, I know that Iconoscope cameras were used for telecine devices long after they had been supplanted by I/O cameras. In this role did they still need to have a live shading console?

1) take a look at this:
http://www.tvcameramuseum.org/bosch/.../kch1000p1.htm
- definitely studio use, as no-one could sling that over his shoulder.
Besides the optics, the lens assembly had resolvers to report the zoom and focus positions, and lookup tables to translate that into barrel/pincushion distortion (used to modulate all three tube scans) and chromatic aberration (used to differentially change the scan size of red, green, and blue).

2) I don't know if for film via iconoscope (which could have as much light as you wanted), what the situation was.
I can imagine several possibilities: a) shading was needed the same as for studio work, or b) it was less of a problem, or c) it was just ignored.
Maybe someone here knows.

The EMI system telecine which used an iconoscope (or emitron as the British called it) I believe used the same camera electronics with shading controls. The iconoscope shading was mostly contributed by secondary emission: highlights, whether from live studio images or the light from a film projector onto the target would I suppose cause the same shading problem.