4K Projector

[cheyworth]

the new Optoma UHD60 and UHD65 look interesting. and at a great price point.

http://petertyson.co.uk/index.php/optoma-uhd60-projector.html?gcpc&gclid=Cj0KCQjwy4zLBRCOARIsADfss37w8A8Vk9JnhUQlyAndHX2GMwObvyvcydx9XjMX_S3xnjkwGgsqFQAaAlV2EALw_wcB

http://petertyson.co.uk/index.php/optoma-uhd65-projector.html?gcpc&gclid=Cj0KCQjwy4zLBRCOARIsADfss36uYL6lPaZ-rZE9S1qTZjutv-C0QwM2fh82O6rdG79kuxlgBEdGG6IaAmgNEALw_wcB

 

[ellisdj]

They are not native 4k projectors, just bear that in mind

 

[bigboss]

According to Evan Powell, editor at Projector Central :

"...this will undoubtedly be an issue of ongoing confusion. Physically the 4K DLP chip has 1/2 the number of mirrors. However, each mirror is used to define two discrete pixels on the screen by alternating its position in sequential refreshes. It is therefore able to address and display the full array of 3840x2160 pixels in the signal. If you look at a 1-pixel grid pattern projected by this 4K chip, you will see each alternating 1-pixel wide line cleanly defined as black and white. Conversely, with the pixel-shift technology used by JVC and Epson, this is not possible. Those machines use native 1920x1080 panels and offshift the pixel array diagonally on each alternating refresh. The maximum number of pixels they can address is 1/2 4K (or two times 1920x1080). Therefore a native 4K signal needs to be compressed to be displayed on these devices, where it does not on the 4K DLP chip. Though Epson and JVC's pixel shift technology is very successful in approximating native 4K video when viewed from typically viewing distances, it cannot reproduce a clean 1-pixel grid pattern like the 4K DLP chip can."

 

[Benedict_Arnold]

^ So basically you can think of those like interlaced vs non interlaced CRT computer screens of old, where, in the interlaced version, only every second line on the CRT screen got refreshed every pass. Now, if the picture refreshes at 120 times a second, or 60 times a second per half, that might not be discernable to anything other than a highly trained human eyeball, but.

AFAIK Sony is still the only manufacturer of native 4K PJs and the midrange model is still about ten grand. On top of that you can reckon on another two grand for a half decent screen.

For me the point is moot, as I don't have the money for either right now, but I'm still waiting to see if any manufacturer comes out with a basic picture only 4K (6K, 8K?) LED/LCD/OLED display in the 100 to 140 inch diagonal range, and how the prices compare to those of a mid range Sony - genuine 4K - PJ and a half decent screen.

85 inch Sony HDR non OLED 4k TVs (XBR85X850D) are on sale at Bestbuy here in Texas at US$6999.99 plus tax at the moment, so I expect 100 inchers to come out around Thanksgiving at the end of November - peak TV buying season in the US -
somewhere (just) under $10,000.

 

[FunkyMonkey]

Benedict Arnold, the ones that only have 1080p chips can be equated to interlacing monitors.

The 4k dlp chip is to all intents and purposes a 4k chip as far as what appears on the screen and what your eyes perceive. That is, if my understanding is correct...they switch mirrors so that at any given time the display is 4k pixels correctly displayed on screen.

 

[Benedict_Arnold]

And a 1080p chip displays the full 1920 (?) by 1080 pixels ALL THE TIME. So a 1080p projector is like a 1080p screen, not a 4k screen.

 

[Benedict_Arnold]

If the light shines on mirror A then is switched to mirror B, how can it be shine light from mirror A and mirror B AT THE SAME INSTANT?

No, the "fauxK" projectors do not simultaneously project 4k pixels, but the two sets of pixels are refreshed so quickly the human eye is fooled into thinking there are. Just like an old fashioned "moving picture" actually displays a rapidly changing sequence of stills.

 

[bigboss]

However, native 4K signal does not need to be compressed to 1080p at all. I'm sure you won't notice any difference when compared with a proper 4K projector.

 

[Benedict_Arnold]

Maybe not. But its still worth knowing a "fauxK" PJ isn't the real deal. Just like all those 720p and 1080i "HD ready" TVs sold 10-15 years ago...

 

[bigboss]

You do agree that these DLP projectors are different to the LCD "faux 4K" projectors, right? Or do you still want to bundle them all under the "faux 4K club"?

 

[Benedict_Arnold]

If it doesn't project the full gamut of 3840 x 2160 pixels ALL AT THE SAME INSTANT, it isn't the full shilling and is therefore "fauxK" in my book, whether LCD, DLP, or lots of little candles.

 

[bigboss]

That's just silly, if you don't even consider the difference.

"4K projectors using either the 4K DLP chip or the 4K-enhanced 3LCD process will accept native 4K signals and then apply some extensive video processing on these signals to prepare them for output to their non-native DLP or 3LCD imaging devices. The difference is that TI's 4K UHD process produces independent single-pixel structures, whereas the 3LCD process does not.

Practically speaking, the most obvious difference between the 4K DLP and 4K-enhanced 3LCD projectors is apparent resolution. The 4K-enhanced 3LCD projectors from Epson and JVC (those currently on the market at any rate) use native HD 1080p chips which are 1920x1080 in physical resolution. Resolution enhancement is achieved by projecting a 1920x1080 image on the first scan, then on the next refresh of the chips a second 1920x1080 image is off-shifted diagonally and overlaid onto the first scan. The total number of addressable pixels in this process is (1920x1080) x 2 = 4.15 million, which is half of the 8.3 million in a native 4K signal.

The 4K DLP chip starts with double the resolution of the 3LCD devices. It has a total of 2716x1528 mirrors. Through some proprietary video processing it is able to deliver two discrete pixels for each mirror. When using this chip in the pixel-shifting process, it delivers double the number of pixels in each refresh compared to the 3LCD projectors. The total number of addressable pixels in this process is (2716x1528) x 2 = 8.3 million, or the same as a native 4K signal. The pixels have been reformulated through video processing to map the native 4K signal information onto this pixel shifted delivery mechanism.

So what do they look like?

The result of both of these processes, as far as the eye perceives, is substantially enhanced picture resolution compared to standard HD 1080p. As far as 3LCD is concerned, though the math says it is half the number of addressable pixels compared to native 4K, from a typical viewing distance the eye will perceive video material displayed on 4K-enhanced 3LCD projectors as much closer to native 4K than 1080p--subjectively the picture does not look like it is "half way" in between 1080p and 4K as the math would suggest. It looks more like it is about 90% native 4K, at least with video subject matter. The bottom line is that when viewing video material from normal viewing distances it will be difficult for most consumers to tell the difference in resolution between a picture produced by a projector using native 4K chips and one using the 3LCD pixel-shift technology.

However, when you switch to something other than video you get a different impression. For example, when you are projecting high resolution graphics or densely packed financial spreadsheets in small fonts, the latent resolution strength of the 4K DLP chip compared to 3LCD pixel-shift becomes much more apparent. When viewing this type of subject matter on 3LCD pixel-shifted projectors, you may tend to see moire patterns in complex graphics, or soft, imprecise resolution of the serifs on small text on a spreadsheet. These details are more acutely resolved with native 4K projectors, or with projectors using the new 4K DLP chip.

Now, with the new 4K DLP chip, the math says that since the physical resolution is doubled as compared to 3LCD, that should push the subjective results on the screen from a perceived (say) 90% of 4K to a potential of 95% 4K. However, once again the math is misleading. This is not what happens. The detail resolution produced by the 4K DLP chip is for all practical purposes indistinguishable from pure native 4K, even when examined from very close up. The ultimate test of this is the display of a 4K resolution 1-pixel line test pattern which contains alternating black and white lines that are each one pixel wide. When viewing this test pattern on a projector using the 4K DLP chip, each line is clean and clearly defined, and you see distinct pixel definition when examining it up close. It is not possible to achieve this level of precision using the pixel shift technology with standard HD 1080p chips.

Therefore, despite the fact that the 4K DLP chip itself has 4.15 million mirrors instead of 8.3 million, we have no problem categorizing the 4K projectors using this chip as native 4K resolution based on the fact that they can display a clean 1-pixel line test pattern. No native 4K projector can do any better. Practically speaking, the number of mirrors on the chip is irrelevant if it can put 8.3 million discrete pixels on the screen and fully resolve a 4K 1-pixel line pattern."

http://www.projectorcentral.com/4k-dlp-projectors.htm

 

[ellisdj]

Its still pixel shifting so its not native 4k so its faux 4k still atm

 

[ellisdj]

Maybe 4k Lite is a better description

 

[abacus]

Think about it like this, interlaced TV supplied an SD image, but it wasn’t native SD as it required 2 passes to create the full image, later TVs displayed the image in 1 go which means it was native SD, however, both provided a full SD image on-screen.

The chip in the new DLP projectors has 4.15 million mirrors (Twice the number of pixels of HD) and each mirror can display 2 unique pixels and as 2 x 4.15 million pixels = 8.3 million this is how the number is derived. Unlike a native 4K chip which displays all 8.3 million simultaneously the DLP has to split the 8.3 million pixels into 2 separate 4.15 million pixel images which it then displays one after the other (2 passes) at a speed that should be invisible to the naked eye, thus the eye only sees an 8.3 million pixel image on screen. (It’s the modern equivalent of interlaced TV)

Now whether it’s identical to native 4K or it has convergence problems like interlaced TV did, only you can see by trying one out. (Whichever way you look at it they can both provide a 3840 x 2160 grid)

As always, get something that suits you, and forget the technology behind it, because it only has relevance for the design engineers, as you as a consumer can’t do anything about it.

Bill

 

[abacus]

A couple of links that may interest you regarding the Optoma 60 and 65 projectors, as it includes a resolution (Detail) comparison to a 4K OLED.

With the new 4K DLP projectors now coming thick and fast it will be interesting to see just how good (Or bad) 1st generation is.

Bill

https://www.tvspecialists.com/optoma-uhd65-vs-uhd60/

https://www.tvspecialists.com/optoma-uhd65-vs-uhd60-part-ii/

 

[Benedict_Arnold]

It's still fauxK in my book.

When (if ever) I have the cash, I'm either going for a native 4K PJ from Sony and a huge AT screen or hanging on for 120 inch picture only wallpaper TVs to become affordable.