Live blog: LG Passive 3D resolution

This morning a shiny 55 inch LG 55LM9600 (the company’s current top of the line model) turned up. I’ve installed it quickly. After doing the physical stuff I made it do a factory default system reset so the TV was starting from a clean slate.

Here I’m going to record my findings on this TV, primarily with regard to the 3D performance.

All my viewing of real 3D content will be at a range of 2.8 metres — double the screen diagonal in accordance with the manual’s instructions. Obviously I shall peer more closely at test patterns.

To start, I popped in the Digital Video Essentials HD Basics disc because on regular TV reception the picture looked a bit edgy. And sure enough the aspect ratio was on 16:9 rather than ‘Just Scan’, which implements 1:1 pixel mapping. I changed this setting. And the ‘Sharpness’ control was set to 25 on a scale of 0 to 100. There was clear ringing around the black lines of the test disc. Turning this down to 0 produced a smooth and accurate picture.

Then I popped in Cats and Dogs 2 yet again to check out its main menu screen:

Cats and Dogs 2 main menu

At the range of 2.8 metres, the jaggies on the dog’s wings were obviously visible and the dog’s fur was noticeably coarser with the glasses on, compared to the smooth and detailed look with the glasses off.

Incidentally, in 3D mode with the glasses on the line structure in the smooth background was visible at range of about two metres, but back at 2.8 metres it was completely absent, resulting in smooth backgrounds.

Sitting back at my computer now, a further 1.2 metres from the screen, the jaggies on the wings and the differences in the fur are just about imperceptible.

This disc has a Roadrunner cartoon on it in 3D, so I ran that, and the picture seemed remarkably edgy. I checked the picture settings and saw that they’d reverted to having the sharpness at 25 again, so I turned that back down to 0, and a much smooth picture resulted. This did little to change the look of the main menu, with the jaggies and course fur remaining.

Note: this was at the default setting for this TV (aside from the sharpness settings mentioned). In particular, LG’s TruMotion was switched on by default, set to ‘Smooth’, so according to LG the TV is doing its 3D at 540p for each eye. I shall now switch TruMotion off and see what happens.

Update 1 (10:05am, original post at 9:38am): Well, I went to the Picture/Picture Option menu and cycled through all the TruMotion settings, including ‘Off’. Something was happening because the TV blanked for the barest instant when switching between ‘On’ and ‘Off’. But what it was doing had no visible effect whatsoever on the picture. None.

Which is odd, because with TruMotion off the picture is supposed to be 1080i (that is, each scan line for, say, the left eye would display in turn the source’s odd and even lines for the left eye, rather than just one of them in the old system).

I cycled through with glasses on, glasses off, normal position, up close, left eye only open, right eye only open. There were no differences. Is the firmware up to date? The Product/Service Info display says that the ‘Software Version’ is 3.00.10. The Software Update facility checked for me, and there is ‘No Update Version Found’. So this TV is fully up to date.

Could it be that this new model TV is not subject to the TruMotion limitations of last year’s models? And that jaggies survive this anyway?

Update 2 (11:27am): Ugghhh! Lots of test patterns. Very difficult to interpret results.

But I am increasingly confident that what I am seeing with this TV at least is that all scan lines are being shown in 3D mode. That is, even though the left eye can see only, say, the odd lines of the display in 3D mode (when you’re wearing the glasses), each of those lines contains both the matching source odd line plus the even source line immediately under it. Invert for the right eye.

Whether these two lines are merged, or the display rapidly alternates between the two is unclear to me. Presumably, judging by what LG was saying about the firmware upgrade for last year’s models, it is the latter. But if so, the alternation is so fast that there was no sense of flicker at all, so the net effect is the same as if the two lines had been merged.

Again, no difference at all was visible based on the TruMotion status.

Short of time, so I will recount another time the test patterns I used and why I think the results that I see indicate the above.

But even if I am right, the fact remains that — even though the 3D is brilliant — in 3D mode these TVs still do not display the full vertical resolution, regardless of what convoluted explanations may be deployed.

I will demonstrate that next week.

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1 Response to Live blog: LG Passive 3D resolution

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