Saturday, August 27, 2011

Sony BVM-E250 OLED broadcast monitor

I had an hour or so to set up a new Sony OLED grade-1 next to a Vutrix HD Pro-24 (their grade-1 LCD display which I like) - the Sony is twice as expensive as the Vutrix (£20k vs £10k). OLED as a technology is supposed to have a number of advantages over thin film transistor (TFT - the important bit of an LCD display. A few are;
  • In a TFT layer the polarisation of light is twisted through 90 degrees to allow the pixel to be illuminated by the virtue of the fact that the front filter is 90 degrees offset from the rear. In effect the transistor stops the light from the fluorescent (or nowadays LED) source. Since the light source is a few millimeters behind the pixel there are chromatic distortions inherent and since thin-film transistors don't shut-off all the light when turned off there are black-level issues. These are the two best known problems with LCD monitors in film & TV grading.
  • Thin-film transistors have a limit to how quickly they can be cycled - typ. 16ms at best (I know some manufacturers claim faster but it's smoke & mirrors). OLEDs can be cycled a lot quicker for better response.
  • In a TFT display the place where the colour is made (the three sub-pixel RGB transistors) is physically separate from the light source - not so with OLEDs where the illuminating LED is also the colour-maker.
So - with deeper blacks and fewer chromatic problems you'd think OLEDs were the way forward. The only thing to consider is the life-span. The blue OLED elements have an estimated life of 10k hours (around a third of the backlight of an LCD). Also - the metameristic character of OLEDs is different and so colour-management tools will need to be upgraded (I just spent £7k on a new LCD photometer!).

I thought out of the box the pictures on the BVM were very good - close to the VuTrix I'd just calibrated to illuminant-D (6504K at 80Cd/m2 for peak white). Response seemed as good with much better blacks, particularly from different angles. The monitor's de-interlacer didn't seem as good as I'd have expected for video-shot material but camera pans etc looked better than the VuTrix.

Overall I was impressed, but not an extra £10k impressed!

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