Friday, May 20, 2022

Why I wouldn't buy a Sony BVM-HX310 in 2022 (if it was my money)

I wrote something similar in 2018 - see Why I wouldn't buy a Sony BVM-X300 in 2018 (if it was my money) which was more of a comparison of OLEDs for HDR monitors vs. dual-layer IPS panels (and specifically the gen.1 Eizo Prominence; the CG3145).

Spin forward four years and I'm no longer working for a reseller but doing my own thing (probably a third of which is colour - calibrating and building LUTs) and I've recently become an Eizo reseller myself (full disclosure!). 

There are essentially three ways you can hit the requirement for HDR in a monitor - and I am surprised how for some people in the industry it is still an alien concept and yet for others it's 100% required. You have to be able to achieve 1,000 Cd/m2 peak white, a reliable D65 white point, ideally >80% of rec.2020 colour space and the SMPTE 2084 EOTF (the PQ curve), along with HLG and maybe even SLog3 and CLog2 (although those ones are really only occasionally needed on set). BUT, most importantly is good black performance as dynamic range is the difference between the lowest difference that can be faithfully represented and the peak light output. Dolby says this should be > 800,000:1 - you really need those dark, inky blacks.

  • OLED - these displays have no trouble with proper blacks (just turn off the sub-pixel elements and no light is output) although the reliability of OLEDs as they approach black is problematic. OLEDs also suffer burn-in - see the 2018 blog for more.
  • FALD LCDs - like the Apple XDR and others you can modulate the LED backlight elements in an effort to overcome LCD's failing of letting light leak past the TFT sub-pixels; you can never get good blacks from a single layer LCD (IPS technology or otherwise) so maybe shut-down the light from the backlight when you need black. The problem with this is that the LED backlight array is never as hi-res as the display panel and so at hard black-white transitions you get a halo effect; very noticeable on star-fields and the like. It's why even the very best Samsung TVs don't look as good as LG and Panasonic OLEDs. In the case of the Apple XDR the resolution is nearly 20Mpixels but it has only ~500 modulated backlight elements.
  • Dual-layer IPS-LCD - Panasonic manufacture a dual-IPS display assembly (4096x2160 resolution) with backlight that the Sony BVM-HX310 and the Eizo CG3146 Prominence both use. The benefit of having two IPS panels is that any light that leaks through the first will definately be caught by the second. In practise this givens those dark, inky blacks that you normally only get from OLED. Turn off the lights in the room, put up a full-frame black field and you really can't see where the bezel finishes and the screen starts, if you've never seen an LCD doing that well with black you'll be suprised.
So, you might think that the choice between Sony and Eizo would be just down to brand loyalty or price (the Sony does list for a few thousand more than the Eizo, but nobody ever got fired for buying a Sony!). However, the Eizo is not just a Sony with a different badge; for my money it improves thus;
  1. Colour workflow – when I have to calibrate an HX310 (or X300) the client will typically say “…we need to have it ready for 709, DCI-P3, DolbyVision (2084/PQ) and HLG” – with a Sony that is the best part of a morning’s work with lots of adjusting bias and gain values, making measurements and re-adjusting; more akin to a 1990s CRT. The Prominence is an entirely LUT-driven monitor and to set one up for those four standards takes ~15 minutes. Even standards that the monitor does not support out of the box (Clog2 or Slog3 as examples for camera monitoring) can be easily added with ColourSpace by uploading into one of the spare LUT slots. Closed-loop calibration with either ColourSpace or Eizo’s (free) ColourNavigator 7 software is automated and quick (like things should be in the 21st century!)
  2. Warrantee – the Prominence has a five-year on-site replacement guarantee. If your CG3146 fails four years and eleven months after purchase Eizo will ship a replacement and repair/replace yours free. This includes colour accuracy and faulty pixels (try and get Sony to stand by a two-year-old HX310…!) - I asked my man at Eizo how many times they've had to break out the stand-by monitor; "...we haven't yet had to" - no failed Eizo Prominence monitors in the UK in five years! You can't say that about Sony's.
  3. Uniformity – I have a customer who has had to send an HX310 back due to poor (i.e. outside EBU 3325 specification) luminance uniformity. The Prominence has Eizo’s DUE (digital uniformity equaliser) which is configured at the factory to give better than delta-0.5 L u’ v’ (as measured on CIE1976) across the whole panel. - here are the measurements taken off an out-of-the-box HX310 a few months ago;

(before you comment, I know these are CIE1931 values in x y Y) - for proper uniformity measurements you need to do CIE1976 L u' v' - I did convert these before calculating the euclidean distance between patches on the gamut. These give rise to a large-scale luma uniformity error >5% which exceeds SMPTE 3325's spec (which is here)

As an aside here is a grab from another bit of monitor uniformity work I did last year;

Anyway, I have a demo CG3146 which I can leave with you for a week (along with lots of hero HDR footage that you can playback off my BlackMagic Hyperdeck 4K - Arri's camera reel, BBC's HLG and Eizo's demo footage) - I also include Sony's SLog3 reel and a LUT loaded into the monitor!