True 4K vs Faux-K

Evan Powell, April 12, 2018

The revolutionary technology of pixel-shifting has injected a lot of controversy and confusion into the world of 4K projectors. People are concerned about what is true or genuine 4K and what is fake or "faux-K." What is the difference, and is it anything to worry about? In the end, as we go about categorizing and defining these products, the practical question is what makes a 4K projector 4K?

A Bit of History

Back in the day, the native resolution of a projector was a big deal, and rightly so. There was a massive visible difference in picture quality between SVGA and XGA, and between WXGA and Full HD 1080p. When comparing these projectors there were obvious differences in detail and image sharpness. Visible pixelation (the screendoor effect) on lower resolution projectors was supremely annoying and desperately to be avoided. Anyone in the projector biz could tell at a glance just from looking at pictures on the screen what the native resolution of the projector was. So we all grew up KNOWING that the "native" resolution of the chips was directly related to ultimate picture quality on the screen.

That was then. This is now. In our new reality of 4K resolution and pixel shifting technologies, there is ZERO correlation between native resolution (the number of physical pixels on the chip) and the actual resolution of the picture you see on the screen. The chip's physical resolution, at least in the home theater world, has become irrelevant.

The revolution began with JVC's introduction of pixel shifting in 2013. This was a radical new approach to getting substantially higher picture resolution out of native 1920 x 1080 D-ILA chips. Epson followed using pixel shifting on 1920 x 1080 3LCD chips. Then Texas Instruments released an 0.66" 4K UHD chip with a physical mirror matrix of 2716 x 1528 which uses two-phase pixel shifting to create 8.3 million pixels, which is 4K UHD. They followed that with an 0.47" DLP 4K UHD chip which has a physical mirror matrix of 1920 x 1080. It uses four-phase pixel shifting to create 8.3 million pixels.

To no surprise, this has fueled a lot of controversy over what is "true 4K" and what is often disparagingly referred to as "faux-4K" or simply "faux-K." This term is widely used by industry personnel, reviewers, and consumers alike. It often connotes that there is something inauthentic and undesirable about the pixel shifting technologies and the 4K projectors that use them. In reality, pixel shifting has produced rapid advances in picture resolution at prices far lower than you must pay for projectors that have native resolution 4K chips. It is a terrific technology that is hard not to love once you see it.

And the simple fact is this: we can no longer glance at an image on the screen and know the physical resolution the chips in the projector like we could before. Today there are 4K projectors using chips in various physical resolution formats -- 1920 x 1080, 2716 x 1528, 3840 x 2160, and 4096 x 2160. And they are all capable of producing impressive 4K resolution pictures. Even the current JVC and Epson models that use two-phase pixel shifting on 1080p chips can produce pictures that come a lot closer to replicating a full 4K picture than one might imagine possible--sometimes they can even beat the 4K UHD DLP chips in the subjective impression of image sharpness.

To illustrate the misleading nature of the term faux-K, let's do some side by side comparisons of six different 4K projectors, five of which are using a variation of pixel-shifting, and one using native 4K chips...

  • Optoma HD60 vs. Optoma UHD50

  • ViewSonic PX727-4K vs. Epson HC 4000

  • Optoma UHZ65 vs. Sony VPL-VW285ES
turn the page for details...


Contents: Intro Optoma UHD60 vs UHD50 ViewSonic PX727 vs Epson 4000 Optoma UHZ65 vs Sony VW285ES
  What Makes a 4K Projector

Reader Comments(14 comments)

Posted Apr 21, 2018 5:32 AM

By Jay

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I’ve been leaning towards the Optoma UHZ65, but has anyone actually played games on this sucker? My last projector was Epson Pro Cinema 9350 and have no clue on that lag time. Obviously I’m not upgrading often but I’ve been happy with my epson.

Posted Apr 19, 2018 2:50 PM

By Brett

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That’s QUITE a twist on what the article was saying. On a 120” screen sitting 9-10ft away, the resolution increase of my Epson 5040UB compared to my older Panny PT-AE8000U was very noticable, and worth the upgrade.

Posted Apr 18, 2018 4:35 PM

By Mark Scott

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Evan, Fantastic real world review. My gut says when 8k or 7680 pixel displays and content arrive that the human eye will not be able to notice a difference in appearance to 4k at a normal viewing distance 1.0 or greater vs screen diagonal size. Good active HDR+ along with 10bit or 12bit color with a powerful bulb or laser source will give a better WOW factory than any increases to resolution.

Posted Apr 17, 2018 7:20 PM

By Reuben

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For the person talking about 110" screens, you're right, 4K is not for you. For those of us pushing 21ft wide screens, yes, we want and need 4K. :)

Posted Apr 17, 2018 7:05 AM

By Roberto

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A system is only as good as its weakest link. Take for instance cheap plastic lense used in expensive 4K Sony projectors. Any conclusions reached based upon the number of discrete elements in the panels are erroneous

Posted Apr 16, 2018 7:42 AM

By SimonBG

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I think the conclusion of this article is this: We didn't need 4k for home use at all. A 30 inch computer monitor that you look at from 3 ft away - sure. But 110" screen from 10-12 ft away and you can barely make the difference. Total waste of money, earth resources and will result in huge electronics waste over the coming years. Thanks for this article, I am staying at 1080p for a few more years.

Posted Apr 16, 2018 7:41 AM

By Brett

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I own the Epson 5040UB, and before I saw the image, I was suspicious about Pixel-shifting, because I had seen some pretty garish video enhancements before (Darbee comes to mind). But pixel-shifting is entirely different, and I look at the image my Epson 5040UB puts out when given 4K Source material, and it is stunning and elegant, and I just couldn't imagine it being any perceptibly sharper. It looks as detailed as any 4K TV which I have seen. So put me in the Pixel-Shifting convert category.

Posted Apr 15, 2018 5:39 AM

By Cory Potts

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Hey Evan, Great write up, really getting the discussion going.

I notice during almost all head-to-head comparisons between native 4K and non-native 4K that there are discrepancies between sharpness/contrast on wither 1080p vs. 4K material. (I've never seen a projector that was the best on both contrast/sharpness for both 1080 & 4K sources)...is this an inherent limitation by the pixel-shifting method? If so, then it must be equally a strength of native 4K (why else would the Sony 285 be sharper than the Optoma UHZ60) as its counterintuitive why a native 4K pj such as the Sony would be sharper on 1080p content than the native 1080p projector (and vice-versa).

I would suggest the definition of "4k" include something about if the projector can resolve sharply a one pixel line ~1/4000 of the image wide, if it can, not sure why it matters how it does it.

Thanks, as always, for your generous amount of time in thoughtful write-ups.

Posted Apr 13, 2018 11:36 AM

By Tom

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Optoma - I wonder if the differences between the phases affects refresh rates in the various 4K formats like 60hz etc and if it impacts input lag in anyway? Don’t the mirrors move and pixel on/ off color changes have to fire 4 times more than a native 1 to 1? This constant jump would make pixel structure less distinct.

Great article thanks.

Posted Apr 13, 2018 8:37 AM

By Adrian Rose

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Even though there is little news here that hasn't been mentioned in passing in the individual reviews over the last few years, I find it very timely and extremely valuable to have this summary and real-world assessment available. Excellent, thanks!

There's far too much focus on resolutions beyond what most of our eyes can perceive, although clearly it's helping to shift a lot of 45"-65" TVs where the benefits only of resolution will be even lower.

Posted Apr 13, 2018 6:59 AM

By Kevin

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I don't think politicizing tech by using fundamentalist and tech liberal is helpful at all. The bottom line is if you're happy with the large home theater image you have regardless of tech, who cares. But there is also objective reality. Notice how there is no debate on what a 1080p projector is. Because it's obvious. Notice how no one argues over whether the Sony VW285 is 4K or not. Hmmm. Why is that?If you have to qualify the statement that your projector is 4k.....It would be much simpler to have 4k and 4k compatible or 1080p+.

Posted Apr 13, 2018 5:13 AM

By Mark Arnurius

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Hey Evan, Since you are talk about the differences between a 2 and 4 phase chip, does that mean they can easily change the 2 phase chip to a 4 phase chip in the future for 8K on the .66 chipset? It makes senses this would work because they have already perfected this on the 1080p chipset, so they probably already have this 8k setup now on a 4 phase .66 chipset. I just hate how they have to come out with so many different formats to keep people buying their products. You know JVC and Epson will finally release a native 4k chip only in a year or so to add their next E-shift technology to take them to 8k when they already have this developed now. I know that we are limited on any 8K media, but having the equipment now only will keep disc media alive because there is no way they can stream this yet and 4K up sampled to 8K would be excellent. Just like how 1080p Blu-ray looks better on these 4K enhanced projectors.

Posted Apr 12, 2018 8:50 PM

By Paul

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Timely writeup of course, thanks. As enthusiasts have known for years, display resolution is not necessarily a major determinant of the final image quality. I recall a decade ago when Dan from Marantz did demos of their 720p DLP vs some then new 1080p projectors that the better lens and contrast of the Marantz yielded an image that was strongly preferred by most. The lens on Sony projectors has been well known as a limiting factor in transmitting true 4K resolution in the lower models.

However I think it may be a bit bold to claim that there is ZERO correlation between chip resolution and perceived detail. Your comparisons are all between projectors that are "one step" apart from each other. What if one of the 2 phase 1080p projectors like the Epson HC4000 is compared to the Sony native 4K? Obviously they are a different price class but the claim is that there is no perceived difference in detail with any of the "faux k" vs "true 4K" imagers, so this comparison begs to be made to substantiate that claim.

Posted Apr 12, 2018 6:35 PM

By Abe

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Good informative post Evan. Let the buyers and sellers beware! So as per the next review/comparison, will the Viewsonic PX747 have a higher contrast ratio than PX727 b/c of higher lumens or is that not related?

That projector and a $300 screen is $1600 for an amazing home theater experience at a fraction of the cost of OLED/QLED/?LED... Thank you for educating us on this!

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