Local dimming not working from 4K HDR bluray source

[TobyCG]

Anyone else noticed this?

When I play a 4K HDR bluray, the local dimming doesn't work.  The setting is locked at Medium and can't be changed but it's patently not working.

Yes I know the backlight is driven to max in HDR mode but there's no reason local dimming shouldn't still work.

If the entire image goes black (such as after logos etc at the beginning of a film) then the dimming kicks in and the screen fades to perfect black but, if there's anything anywhere on the screen at all, the brightness level goes up across the whole screen, as if local dimming was disabled.

Oddly I only notice this from a 4K HDR bluray source, if I play 4K HDR content from Amazon Prime (such as The Grand Tour for example), dimming works fine.

This is clearly a bug and I've reported it to Sony but, as usual, their support is atrocious and they seem totally disinterested.

[TobyCG]

@AnonymousApologies for not getting round to sorting a concise chronological list of my issues but frankly they've now paled into insignificance next to my latest problems.

TV failed completely on 1st Feb.  Wouldn't power on.  Googling suggested a failed 'DSP' board which a lot people have reported failures of.

Engineer turns up on 4th with a replacement board, fits it and all is working again.  Until last Friday when it failed again!

I am now having very heated conversations with John Lewis and Sony about this as I've had enough.

[Kuschelmonschter]

We have a similar topic over at the German forums, see here.

[TobyCG]

---

@Kuschelmonschter wrote:

We have a similar topic over at the German forums, see here.

---

Well my issue was solved by enabling MotionFlow but it appears that's not your issue as you have it enabled.

When my TV is finally fixed, I'm not going anywhere near the MM update - looks like a total disaster.  Even when Sony re-release it and claim it's fixed, I won't trust them an inch.

[Kuschelmonschter]

It might still be the same issue. The whole settings system is hardly predictable with several settings depending on each other for no obvious reason. And there is no documentation of course.

That's why the support always tells you to do a factory reset. That pretty much tells you the state of the whole thing. It is too easy for customers to break things until the TV is hardly usable anymore.

It is also not clear to me how the factory reset works. Does it really clean up all the mess you have done? I think it is just another (buggy) software which deletes/replaces some files.

[TobyCG]

A factory reset should just clear all volatile memory where all user settings are stored, thus returning the set to default values for everything.

Whether it actually does that on the Sonys is another question.

[RedHagar]

I'm having the same problem. Sony x900e with a Samsung UBD-M7500 4K BluRay player. Watching Black Panther but nothing is black! As soon as HDR kicks in all local dimming disappears. The input source even blooms all around the white text and it looks terrible. Disabling HDR does not fix it either. Motion was enabled and set to smooth, tried True cinema and was very slightly better. Just really, really disappointed in all HDR BluRay discs I've tried so far. Star Wars Last Jedi also looks terrible. 

[RedHagar]

Okay, so I did some more playing with settings and I did find one item that made a huge difference. That is the auto picture mode. I had it set off. I noticed even the Sony screensaver coming on with a huge blooming effect around it as it moves around the screen. It was also very jittery. As soon as I set auto picture mode in to 24p, the local dimming kicked in and the smooth motion also kicked in and everything improved dramatically. This should be posted somewhere! One setting should not render a $2000 TV useless!

[RedHagar]

Okay, so I did some more playing with settings and I did find one item that made a huge difference. That is the auto picture mode. I had it set off. I noticed even the Samsung screensaver coming on with a huge blooming effect around it as it moves around the screen. It was also very jittery. As soon as I set auto picture mode in to 24p, the local dimming kicked in and the smooth motion also kicked in and everything improved dramatically. This should be posted somewhere! One setting should not render a $2000 TV useless!

Also...I really can't post things within an hour of each other? That's really stupid...

[Kuschelmonschter]

If I remember correctly, all that the Auto Picture Mode does is setting picture mode to some Cinema mode when a 24p source is detected. I assume that you misconfigured something in your other picture mode. So which picture mode to you usually use and what are your settings for Local Dimming and X-tended Dynamic Range Pro?

[RedHagar]

I'm well aware of what auto picture mode is supposed to do...but it completely changed the picture. Dynamic range and local dimming are both set to high. Brightness is at max.

On all SDR sources, everything looks great. 

I will have to test this on some of the Netflix titles now and see if it makes any difference with those...