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 UHD60 vs Optoma UHD50

In our first test, we will compare projectors using the two new 4K UHD DLP chips. We can do this by setting up the Optoma UHD60 with its 0.66" chip sporting 2716 x 1528 mirrors, and the Optoma UHD50 with its 0.47" chip, having just 1920 x 1080 mirrors. The UHD60 has two-phase pixel-shifting to double the number of pixels on the screen while the UHD50 has four-phase shifting to quadruple the number of pixels. Let's put these two projectors side by side and take a close look.

Viewing the pictures close up, at a distance of 12 inches from a 5-foot wide image, you can see an obvious difference in pixel structure. The UHD60 with its 0.66" chip and two-phase shifting produces a distinct pixel structure. Each pixel is extremely small of course, but you can see clearly distinct pixels in rows and columns when you examine the image close up.

On the UHD50, when you are at the same distance of 12 inches from a 5-foot wide screen, you can detect an extremely subtle hint of pixel structure, but it is nowhere near as distinct as on the UHD60. There is no sense of discrete individual pixels. This is true of the ViewSonic PX727-4K as well which uses the same 0.47" chip. The indistinct pixel structure on these projectors is a feature of the four-phase pixel shifting going on with the 0.47" chip.

Once you back up to a viewing distance of two feet from a 5-foot wide screen (that is, 0.4x the screen width and a lot closer to the screen than anyone would want to be when watching a movie), all hint of visible pixel structure disappears on both projectors. At this distance the UHD60 and the UHD50 look the same, at least in terms of detail resolution.

Is there is any visible difference in image sharpness? The answer is clearly no -- in practical terms you see exactly the same amount of image detail on both models. The fact that one projector's chip has a mirror matrix of 2716 x 1528 and the other a matrix of 1920 x 1080 (half the number of mirrors) has absolutely zero impact on the sharpness and detail in the image.

This does not mean the pictures look identical. There are other contributing factors on a projector that affect what you perceive as image sharpness. In this case digital noise is a factor - the lower the noise the cleaner and sharper the picture looks. And in this regard the UHD50 tends to edge the UHD60 with an overall lower noise factor.

In addition, one of the biggest factors influencing what you see as image detail and sharpess is contrast. In this case the UHD60 is higher in contrast than the UHD50, and in many scenes this contributes to the perception of it being the sharper of the two projectors. But at the end of the day, both the level of digital noise and the projector's contrast have more impact on one's perception of the sharpness and the ability to resolve detail on these two projectors than does the physical resolution of their chips, which is a non-issue.

ViewSonic PX727-4K vs Epson Home Cinema 4000

This is a different comparison entirely. The ViewSonic PX727-4K has the 0.47" DLP chip with a 1920 x 1080 mirror matrix, generating a 4K picture (8.3 million pixels) via four-phase pixel shift. Meanwhile, the Epson HC 4000 uses 3LCD chips with the same 1920 x 1080 pixel matrix, but it has only a two-phase pixel shift. So it does not produce 8.3 million pixels, and Epson has never represented that it did -- they market this class of projectors as 4K-enhanced. So the HC 4000 paints two slightly offset 1920 x 1080 images per frame while the PX727-4K paints four. In theory the PX727-4K should produce a sharper picture in terms of image detail, and it does.

So, what differences do we see? When viewing the Epson HC 4000 from our close-up distance of 12 inches from a 5-foot wide screen, there is no distinct pixel definition. The two-phase shift in this implementation tends to blur any hint of a discrete pixel matrix. In this regard it is extremely similar to the PX727-4K. When viewed very close up they look not quite perfectly identical as far as the indistinct pixel array is concerned, but they are pretty darned similar.

Now, let's back up to a more practical viewing distance. This time we will stand 5 feet from our 5-foot wide screen (1.0x the screen width). Can we see any difference in image sharpness and detail? Yes, the PX727-4K is the sharper of the two. And this is true no matter if you are displaying a native 4K video signal, or if you are displaying regular HD 1080p and having the projectors upscale it. It is not surprising that the PX727-4K can deliver more 4K detail from a 4K signal, but it is surprising (to me anyway) that it can even upscale HD 1080p with a higher apparent level of precision. This four-phase pixel shift is remarkably potent as far as rendering detail is concerned.

HOWEVER. And this is a huge however - the Epson HC 4000 is much higher in contrast with much more solid black levels than the PX727-4K. And as we know, high contrast makes a picture look sharper. So when we back up from the screen to a viewing distance of 1.5x the screen width and put on some 4K HDR material, the Epson 4000 actually appears to be a bit sharper than the PX727-4K.

This is due to a combination of factors - as you move back from the screen the advantage the PX727-4K has in rendering fine detail becomes less visible so contrast becomes a more dominant factor in your overall perception of the picture's sharpness. So as your move back your perception flips and the Epson 4000 looks like the sharper of the two projectors.

The point at which this occurs depends on the contrast of the subject matter, but with the 4K HDR movie Lucy it appears to happen at a viewing distance of about 1.3x the screen width (with my 20/20 vision). In point of fact, the effect is somewhat of a hybrid, with some elements in the picture looking sharper on the PX727-4K, and other elements looking sharper (or at least as sharp and more three-dimensional) on the Epson 4000. In this no-man's land, where the latent competitive strengths of both projectors are visible simultaneously in the same picture.

In the end, this comparison illustrates that contrast is a huge mitigating factor that can outweigh the perception of image detail, sharpness, and clarity. Small differences in image detail which are obvious when examined close up become insignificant or even invisible when you sit back to enjoy a movie in a typical theater set up. Meanwhile, contrast is of utmost importance.

Optoma UHZ65 vs Sony VPL-VW285ES

Can you see the difference?

The Optoma UHZ65 ($4495) is a laser-based 4K projector using a single 0.66" UHD DLP chip with two-phase pixel shifting. The Sony VW285ES ($4999) uses three native 4K resolution SXRD panels. So these two models compete directly both in resolution class and price. The big question is, can you see the difference between a projector using authentic native 4096 x 2160 resolution chips, and a projector using two-phase pixel shifting on a native 2716 x 1528 chip?

Once again, we start by doing some pixel-peeping close up, from a distance of 12 inches on a 5-foot wide screen. And at this distance, the pixel structure of the two projectors is obviously different. Both have discernable discrete pixel structure, but the pixels on the UHZ65 are (by comparison) larger and more well-defined. The VW285ES's pixel structure is so small as to be almost invisible, but on very close examination you can detect the pixel pattern.

Thus, in theory, if the number and size of discrete pixels has anything to do with it, the VW285ES should be able to resolve more detail than the UHZ65, assuming the three chips on the VW285ES are perfectly aligned. To detect any visible differences, the detail must exist in the source to begin with, so we need to use a 4K source. Once we've put the 4K material on the screen, the issue then becomes whether there is a level of fine detail that can be resolved by the VW285ES that cannot by the UHZ645, and whether this incrementally resolved detail is visible to the viewer at a typical viewing distance.

Since few people would ever want to sit closer than 1.0x the screen width, we set up to view at a distance of 5 feet from our 5-foot wide images. Popping in the 4K HDR disc Lucy gives us a good test sample for video as it is loaded with fine details in hair, leather and cloth fabric, etc.

And the results? In this movie there are definitely certain elements in some scenes which are rendered with slightly more detail on the VW285ES. This occurs in the first scene, where detail in the straw hat and the subtle texture of the leather jacket are more successfully resolved by the VW285ES. However, at the same time, the hair detail in the Scarlett Johannson close-ups appears to be better defined on the UHZ65. Why is this?

Once again, the big issue is contrast - the UHZ65's 4K HDR picture is substantially brighter and noticeably higher in contrast than the VW285ES. The increased vibrancy of the UHZ65's picture makes it look subjectively sharper even though it isn't. Once you move to a viewing distance beyond 1.0x the screen width, the eye's ability to resolve the subtle differences in detail between these two projectors evaporates. At this point the physical resolution of the chips in these two models has nothing to do with perceived image sharpness. Contrast (and other factors like digital noise, lens resolution, and video processing) become the determining factors in one's perception of the picture's overall sharpness. In other words, in this case we have a projector that many will dismiss as "faux-K" actually beating a "true native 4K" projector in perceived image sharpness.

Let's now consider the display of an HD 1080p picture rather than 4K HDR. With an HD 1080p source, we no longer have the extreme detail in the source itself. Both projectors are upscaling a 1920 x 1080 signal to a 4K-like image. With these two projectors, with respect to detail definition itself, there is very little if any discernable difference between the two pictures, even when viewed close up.

However, with HD 1080p we once again encounter a big difference in contrast, except this time the VW285ES wins. In default Cinema presets, when displaying HD 1080p source material, the VW285ES is much higher in contrast and saturation than the UHZ65. So the VW285ES looks subjectively sharper and more three dimensional despite the fact that there really is no additional detail in the picture. At any normal viewing distance beyond 1.0x the screen width, the differences in perceived sharpness of upscaled 1080p material is entirely attributable to factors other than the physical resolution of the chips. Whether it is true 4K or faux-K has nothing to do with it. Contrast is king.

What Makes a Projector 4K?

Since "4K" is all about resolution, it is not surprising that so many folks have been preoccupied with native 4K vs. pixel shifting 4K, and debating the merits of each. Though many folks use the term faux-K as simply synonymous with pixel-shifting technology without implying anything derisive, many use it precisely because it insinuates inferiority. When it is used in this manner it is counterproductive and serves no good purpose.

This preoccupation with the physical devices is unfortunate since it causes the unsuspecting consumer to get fixated on what is the least relevant aspect of 4K projection technology (at least as far as home theater is concerned) -- which is the number of elements on the device. All of these 4K projectors regardless of chip type are able to create images in a class that is legitimately understood as 4K resolution. Even the JVC and Epson models with their simple two-phase shift on 1080p chips can outperform competing 4K projectors on the basis of contrast and black levels and produce pictures that look equal to, and in some cases better than, a competing 4K projector at a similar price.

So the bottom line is that there are many important factors that contribute to a 4K projector's success. Certainly contrast is a critical one--both with HDR and SDR. But also the level of digital noise, the image enhancement video processing, the color balance and saturation, and the optical precision of the projector's lens, all contribute to making a 4K projector's picture great or less than great.

Unfortunately, all of these vital factors tend to get sidetracked when the consumer becomes preoccupied with the almost irrelevant issue of device level resolution. While this used to be a hugely important spec in the projector business, it is no longer an issue of consequence in the world of pixel-shifting 4K for home theater projectors.

Now, before you go dropping me a flaming email, I am NOT arguing that native 4K imaging devices are irrelevant, or that native 4K devices cannot be a critical feature in a projector. They most certainly can be. There are projection applications that WILL benefit very directly from native 4K resolution devices. If you are displaying still complex graphics in large scale, with viewers being particularly close to the image, the incremental resolution that can come from native 4K chips (like that which can be seen close up in the Sony VW285ES vs Optoma UHZ65 comparison) can be both visible and relevant to the application.

In point of fact, Digital Projection, Inc. just staged a demo of the first 8K projector in Las Vegas at the NAB tradeshow this week. So not only does native 4K imaging have a set of applications for which it is uniquely advantageous, 8K does too, and it is coming sooner than you think.

And even in home theater, if you have a much larger than typical screen and you like to sit in the front row of a movie theater, the incremental picture resolution from a native 4K projector may be visible and relevant to you. But this is simply not the typical desired set up in consumer home theater.

So what exactly is a 4K projector?

The term "4K projector" is open to any of several interpretations, and there is no chance of a consensus--it is an emotional subject for a lot of folks. Strict fundamentalists will say the term should be reserved exclusively for projectors that have native 4K imaging devices and that no pixel shifting machine should qualify. At the opposite end of the spectrum are the tech liberals who believe that if the projector takes a 4K signal and does something to make it look like an exciting, high resolution 4K picture on the screen, that is really what it's all about.

While I prefer the latter definition myself, what I care more about is that buyers come to realize that the differences in detail resolution between all of these various 4K implementations are extremely trivial compared to the major issues of contrast, brightness, color balance and saturation, and image stability and clarity that ultimately define the greatness of a home theater picture.

Comments (41) Post a Comment
Abe Posted Apr 12, 2018 6:35 PM PST
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!
Paul Posted Apr 12, 2018 8:50 PM PST
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.
Mark Arnurius Posted Apr 13, 2018 5:13 AM PST
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.
Kevin Posted Apr 13, 2018 6:59 AM PST
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+.
Adrian Rose Posted Apr 13, 2018 8:37 AM PST
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.
Tom Posted Apr 13, 2018 11:36 AM PST
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.
Cory Potts Posted Apr 15, 2018 5:39 AM PST
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) 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.
Brett Posted Apr 16, 2018 7:41 AM PST
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.
SimonBG Posted Apr 16, 2018 7:42 AM PST
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.
Roberto Posted Apr 17, 2018 7:05 AM PST
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
Reuben Posted Apr 17, 2018 7:20 PM PST
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. :)
Mark Scott Posted Apr 18, 2018 4:35 PM PST
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.
Brett Posted Apr 19, 2018 2:50 PM PST
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.
Jay Posted Apr 21, 2018 5:32 AM PST
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.
HoustonHokie Posted May 21, 2018 2:38 PM PST
I bought my dad an Epson 5040UB last year and I recently bought an Optoma UHZ65.

A couple of observations: The Epson has no business looking as good as it does with a 4k image source. It's ridiculous how crisp it is. I heartily recommend it.

I still bought an Optoma UHZ65 (sight unseen) because I wanted each of the 4K pixels provided from my video source displayed (which the Epson doesn't provide) and I thought the UHZ would make a difference.

But first, I certainly agree with the author on his findings for the setup he described.

My issue with this review is that the observations were taken from a 5' screen. Who is buying a projector of this caliber for use on a 5' screen? Yes, if you ask me 4k is probably a waste for a 60" screen. However, it's not realistic use of these devices.

Our setups are 10-11' screens and I absolutely want to get up close for that immersive feel and not see the pixels. At 10 feet, I could easily make out the pixels on my old Epson 3010. On the UHZ65, I definitely can not. It's as sharp as advertised to the point of tricking my poor wife's brain and giving her motion sickness when watching an intense action sequence. It looks real and covers your line of sight at the same time. The Planet Earth 2 sequence with the baby lizards and the snakes is gut wrenching stuff.

The Epson's amazing contrast in darker scenes is noticeably better than the UHZ and that does count for a lot, but pops has a windowless room to play with and I don't. The UHZ's blazing 3000 lumens works better for my ambient light situation. Those 4k games are unreal on this thing.

Regarding the validity of pixel shifting 4K being faux-k. I haven't noticed it to be an issue. My boss has a high end Sony with native 4k resolution and I can't tell the difference in resolution or refresh speed with respect to the pixels.

However, the UHZ has a noticeable "rainbow" affect. This is due to the same light source being used for the three projected colors via a spinning color wheel. I only notice it when turning my head or if a particular action sequence is moving quickly enough, but it's there. I will upgrade a few years down the road just to get rid of that issue.
Evan Powell, Editor Posted May 21, 2018 4:05 PM PST
Houston, nobody is suggesting these projectors be used on 5' screens. You get maximum benefit from 4K projectors when using them on 100" or larger screens, depending on your viewing distance. The 5' images in this test were used simply for comparative evaluation of the projectors when they are both projecting the same size image. You get the same results if you compare them at any size when maintaining the same ratio of viewing distance.
Felix Posted Nov 23, 2018 1:10 PM PST
Interestingly and curiously, the editor of this article has chosen to compare just one part of the 4K UltraHD specifications, the resolution (which is let’s say about 1/3 or even just 1/4 of UHD), and actually leaves out the MAIN and MAJOR part of it, the HDR and Wide Color Gamut (WCG), which, if you read and document yourselves, you’ll find out is actually what makes UHD new and best, and makes images look so good! And rest assured, those features are the ones responsible for the better contrast noticed in the article. Sure, good contrast comes from other things too, such as the light source (type, efficiency, etc.), optical system, and so on, but from a UHD point of view, HDR and Wide Color Gamut are mostly the ones that make good contrast and definition!

Of course, one might argue that projectors aren’t currently “there” yet with HDR and Wide Gamut standpoint, and they are still struggling hard to display them. But if we’re talking about 4K UHD and leaving out HDR & HCG we’re actually NOT talking about 4K UHD. Instead we’re just comparing resolutions.

That’s just my humble opinion, as an avid movie watcher, which had found this article while searching for more GOOD information about 4K UHD projectors since I’m looking out for a replacement of my old and good projector. I'm not for a second wanting to be dismissive or to offend anyone; just wanted all of us to have real, complete and good information before we go make our choice!
Rob Sabin, Editor Posted Nov 26, 2018 1:08 PM PST
Thanks for your comments, Felix. I think may people will agree that resolution was the first but not necessarily the most impactful feature of the UHD format. HDR in particular does have the potential to alter the viewing experience for the better, though more so with high-light-output flatpanel TVs than with projectors, which do indeed struggle with hitting the highlights in an impactful way. That said, resolution is indeed a very critical aspect of the front projection experience given the larger screen size. This article was very specifically about comparing the perceived image detail of 4K-resolution projectors vs. 1080p-resolution projectors that accept 4K content, make use of HDR and wide color gamut encoding, and use pixel-shifting to bring more perceived detail to the screen. The writer's conclusion -- that the differences in perceived detail are fairly minimal -- suggests that buyers are free to focus more on other factors that will improve the image quality (higher rated contrast, better rendering of HDR for example) or improve the set-up or user experience (powered lens functions, etc.).
Jim Posted Jan 7, 2019 10:13 AM PST
Has anyone addressed the durability/longevity of phase shift DLP projectors?

My last DLP projector started getting stuck pixels as it got old. It seems that faux-K dlp phase shift projectors will not last as long since they have to perform up to 4x as many on/off cycles vs. a native 4K DLP chip. You also have the additional failure mode of the phase shift movement itself.
Scott Wallace Posted Mar 16, 2019 5:50 PM PST
Thanks for the article. I appreciate the thoroughness and the acknowledgement that not everything involving picture quality is about the number of pixels. But......there is one inescapable fact and I can scarcely believe this doesn't get talked about more. It begins with this notion that detail is somehow irrelevant once one can no longer discern individual pixels. This is simply not the case. Consider what you experience when you see an image from a high-end DSLR on a TV or computer monitor or phone or tablet. When you see a similar image, but one taken with a camera of lower quality, even if you can't discern pixels, there is no question as to which picture has more real data and more information. It is the resolution and resolving power of micro-contrast that is a direct byproduct of fine detail retrieval. Yet if you're looking at such images on anything other than an actual print, you are looking at a finite number of pixels equal only to what any given display can reproduce. And yet, even with tiny pixels and huge PPI numbers, the higher resolution photograph is obviously superior and anyone can tell that there is more information. There is source resolution and there is pixel resolution. With true 4K source material, a true 4K projector that is displaying simultaneously the entire array of pixels will have an advantage in actual information visible. Now that doesn't mean that a projector with superior contrast or more accurate color won't be deemed superior in overall enjoyment. But......true 4K is still a different animal than Faux-K. Pixel shifting technology is clearly a leap over straight 1080p. But let's not be so eager to jump on the 'megapixels/resolution doesn't really matter' train that we forget that micro-contrast and fine detail are what more pixels and higher resolving power make possible. It seems like it's become vogue to think one more 'in the know' if you bag on 4K and start touting the virtues of other things because it makes you sound like you have some kind of hidden knowledge that the masses aren't privy too. Faux-K is great. True 4K, provided color and contrast are of similar high quality is still a different and better beast.
Captain Jack Posted Dec 7, 2019 12:56 PM PST
This is a fantastic article. It's well organized, well written, objective, and well supported with concrete examples. Thanks for taking the time to share your insights and clearing up this (potentially) confusing topic for many.
Rajeev Posted Apr 30, 2020 3:39 PM PST
Well written, well explained. Thx
Seth Greenbaum Posted Jul 14, 2020 7:14 PM PST
This is super helpful. The upshot is that there seems to be a narrower spread between the low end and high end in the 4K realm, at least in terms of resolution. (So the low-end 4K projectors are not “terrible” the way some low-end 720p projectors were). But as always it comes down to the overall optical path.
Jose Luis Pelaez Posted Apr 15, 2021 4:03 AM PST
Jim, After studying the operation of the XPR module with its pixel shift to achieve an apparent resolution of 4K, I think that the micromirrors cycle of the DMD chip is the same as in FHD. What is moving is the XPR lens (x4) synchronously with the RGB settings of the DMD chip. What is questionable is the life of the XPR module, aside from the noise it makes.
Isaac Posted Oct 8, 2021 3:17 PM PST
My question is - if I use a 4k pixel shift projector such as a BenQ TK700STi, would that automatically upgrade ALL of my viewing experiences? Let me be more specific, would all the 1080P videos that I am used to watching on my epson 1060 appear to be more crisp and be automatically enhanced? OR do I need to play a video/movie/video game in 4k resolution for the projector to project in 4K? Since we are not relying on native 4k resolution, I am asking will the pixel shifting technology manipulate my 1080 youtube video into looking like 4K?
Rob Sabin, Editor Posted Oct 9, 2021 8:52 AM PST
Good question. The short answer is yes, you will enjoy enhanced detail with 1080p content on one of these 4K-friendly projectors. That holds for all 4K compliant projectors that rely on pixel shifting -- whether we are talking about a 1080p projector that doubles the pixel count for something in between 1080p and 4K resolution (like the Epsons), or a full 4K projector that puts all the pixels in a UHD signal on the screen using pixel shifting (ie, all the single-chip 4K DLP models). What happens is that the projectors internal scaling converts the input signal, whether 1080p or something less, to 4K and then applies that converted 4K signal to the pixel shifting process. If the scaling electronics are good, you'll get a good result with your 1080p content. Fortunately, the 1080-line to 2160-line conversion on most TVs and projectors today is excellent, aided by the fact that it's a simple doubling. 720p to 4K conversion (as you might experience coming from a cable box on certain channels) is more complex and not always quite as clean, though most set-top boxes will perform a conversion from 720p to 1080i or 1080p before sending it to the display -- probably with worse results than if you let the display do it.
David Posted Jan 23, 2022 5:25 PM PST
Pixel shifting was and probably still is used as a con game to convince people to buy a projector they thought they were getting instead of what they were actually getting. I despise these Companies playing this game. I’ve seen no such projector that is 1080p look like a 4K image. You’re full of horse malarkey if you actually think you’re capable of making that happen.
Rob Sabin, Editor Posted Jan 31, 2022 2:00 PM PST
I'm bored with folks trashing the concept of pixel-shifting because they either haven't seen it with the top-line models and don't believe it's a viable alternative to very expensive native 4K projectors... or they just hate the idea. But to call it a "con game"...or a "game" at uninformed and arrogant. If I couldn't afford a native 4K projector--and I can't--I'd be absolutely delighted to spend my days being full of horse malarkey and enjoy the benefits of 4K HDR content on a pixel-shifting projector...which I do.
Bob Posted Feb 1, 2022 2:30 PM PST
Rob - I agree with your comment above. The projectors that can display the full 8.3 million pixels have now won countless awards from the toughest critics using lamps, lasers, and LED light sources over many years since the article was written. With true UHD content now available on nearly every media source imaginable, a projector that specifies a full UHD specification is the best chance to see every detail that is in the content. Combined with HDR - we now have affordable projectors that can display pixel correct images at 2-3 times the size of a 75" TV - enabling massive size home theaters and 4K simulators at affordable price points.
Joe Posted Feb 13, 2022 10:49 AM PST
Question, do all 4K projectors automatically (default attempt) upscale all 1080p content? Only Pixel shift 4k projectors? Only native 4k projectors? Both?

The reason I ask is because my gaming pc performs excellent at 1080p but doesn't carry the muscle to play 4k smoothly. Solution? Get entry level 4K projector with good contrast to just upscale all my gaming. Streaming 1080P videos also helps since my internet speed is lacking, so streaming 4k isn't ideal. I am hoping to upgrade to faux 4k while keeping gaming and video streaming at 1080p. Is this realistic? Don't want to buy a 4k projector that wont automatically upscale my projected 1080p content. Thanks Rob for all you do!
Rob Sabin, Editor Posted Feb 14, 2022 2:13 PM PST
Joe, all TVs and projectors must by definition upscale or downscale a video signal internally so that it matches its native display characteristics, though some, like the native 1080p Epsons that accept 4k/HDR, do give you the option to manually turn off the pixel-shifting enhancement with 1080p signals and just view those signals organically via the 1080p chips without processing. Likewise, we've seen something similar in a few single-chip 4K/UHD DLP models that use the 0.47-inch 1080p DMD before applying XPR pixel shifting for 4K; there's a mode where you can turn off the 4-phase pixel shifting and just view the output of the DMD prior to the shifting. But every 4K projector you buy will end up scaling up to 4K to fill out its pixel count with a 1080p signal, whether it's a native 4K JVC or Sony, a full-4K DLP projector that does pixel-shifting, or an Epson with 1080p chips that doubles the pixels with Epson's enhancement. And it always looks better than native 1080p would.
Lee Posted Feb 16, 2022 7:14 AM PST
Great editorial. Just wondering, I recently had a Optoma uhd51 which uses the 1080p chip of which the picture was really nice but could not get over seeing the black ( grey light) spillage from around the picture. What is this? I've never had a 1080p projector with this problem why do the uhd dlp's have this, makes me wonder if we are getting a uhd picture made from less than the chip can produce.
Rob Sabin, Editor Posted Feb 16, 2022 8:07 AM PST
Lee, you are referring to a known engineering feature of at least the 4K DLP DMDs that causes this false dark frame around the image. It has been reduced in size and its "noticeability" in the most recent generation of chips, but it's a reality for all single chip 4K DLPs as far as I know, at least those using the 0.47-inch DMD. The larger your image the bigger the frame. A screen of reasonable size with a standard black felt frame will usually hide it, but if you project on a wall or maybe have a screen with a fine bezel it's just there. Sorry...

Lee Posted Feb 16, 2022 12:16 PM PST
Thanks for the reply Robin. To be honest I use just a pull down screen as it's in my living room. I honestly found it such a distraction in dark scenes that I've gone back to a 1080p projector. I reckon it should be a spec of the projectors so when we use your site's screen calculator ( been using for years! And has been a god send) You could calculate how far the light overspill would be. But hey ho I don't think it would be something the manufacturers would reveal. Thanks again.
Rob Sabin, Editor Posted Feb 16, 2022 12:58 PM PST
Understood-people have complained about it for years, but the alternative would be to go with a more current 4K DLP where it's not as obvious or a 4K three chip projector.
kminnehan Posted Apr 20, 2022 12:46 AM PST
This article is terribly one side and doesn't mention any of the negative side effects of image shift like the shimmer and artifacting you can see when there's a ton of motion on screen. It might be fine with static images but movement causes visual problems.
george Posted May 10, 2022 2:27 PM PST
This is a a great write up but I question the use of a small 5 foot screen. Nobody I know of with a projector uses such a small screen. Better comparison would be to use a much larger screen 10ft, or so . The differences might be more obvious
Rolando Posted Nov 15, 2022 1:33 AM PST
In your opinion, how much of a difference does Dolby Vision make in a projectors image definition. Is it the end all?
Rob Sabin, Editor Posted Nov 15, 2022 8:19 AM PST
Dolby Vision is a high dynamic range format that isn't quite directly related to image definition above and beyond the ways in which image dynamic range (ie contrast ratio) affects our ability to see detail. If you're asking more generally about the emotional/visceral impact HDR has on our viewing, I'd say it varies very much by projector because of the typical lack of brightnesss in projection displays; the otherwise high impact nature of HDR on flat panels can be easily lost on a projector and you can end up with what amounts to standard dynamic range but with wider color gamut found in HDR content. On the other hand, the best projectors do a great job of noticeably boosting highlights and delivering deeper blacks vs SDR, which is the goal of high dynamic range in the first place.
Brent Posted Jun 20, 2023 7:17 PM PST
Hey Rob,

For any pixel shifting 4K projector, does the projector actually use the 4K source information or does it upscale a 1080p signal? For a projector that pixel shifts (2 or 4) but does not have a full 4K resolution (like the Epson 5040), if it is using the 4K source, what information is "thrown away" in each frame? Are there any good articles that cover this topic? I am having a hard time finding this information.
Rob Sabin, Editor Posted Jun 21, 2023 7:14 AM PST
Brent, technically speaking, anything we would call a "full 4K" pixel-shifting projector uses every bit of information in an Ultra HD signal (3840x2160 pixels) for each frame. The information is broken into two or four sub-frames (depending on the native resolution of the imaging chip being used) and the full signal information is flashed up on the screen within the time requirement of a single frame. Nothing is truncated or lost. All the single-chip 4K DLP projectors fall into this category; the more common 0.47-inch DMD chip has 1080p (1920x1080) native resolution and gets a 4-phase pixel shift, while the larger 0.66-inch DMD has a native 2716x1528 mirror array that only requires a 2-phase shift in the space of a single frame to put all the UHD pixels on the screen.

The Epson "4K PRO-UHD" projectors, such as the Home Cinema 5040UB, HC5050UB/6050UB, HC4010, or HC2350, as well as older JVC projectors that are not native 4K, merely double the resolution of a trio of 1080p LCD chips or, with the JVC projectors, LCoS chips. That results in about 4 million pixels on the screen vs the 8 million in a full 4K projector. I do know that the signal is not downscaled, but whatever logic is used to decide what to throw out is proprietary as far as I know. Epson, at least, has a lot of research and engineering invested in how to electronically enhance visual detail for these half-4K presentations to make them look convincingly like full 4K from normal viewing distances while taking advantage of the blurring of the pixel grid that results from pixel shifting. However, doubled 1080p very quickly reveals screen-door effect as you approach the screen, and while Epson does a good job with this, a good argument can be made today that this approach should be retired circa 2023. They have already done so in their flagship projectors the LS12000 and LS11000, which do perform a 240Hz, 4-phase pixel shift on native 1080p res LCD chips to put all the UHD pixels on screen. That will be added as an option to their commercial large venue projectors next year, and it won't surprise me if we soon see a full 4K home theater model at something less than the LS11000's $4,000 cost. I'm not speaking on any inside information, but the 5050UB is long in the tooth and a $3,000 full-4K model laser or even lamp-model as follow-up to the LS12000/LS11000 would be an obvious replacement.

In conclusion, while the doubled up 1080p in Epson's 4K PRO-UHD models have a distinct disadvantage to full-4K pixel DLP pixel shifters, the Epson 3-chip projectors do offer the very real advantages of immunity to rainbow effect artifacts, and 100% color brightness equal to the white color brightness.

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