Vivitek Qumi Q6 portable projector test: small, but shows like a big one

If you are used to squeezing everything out of the device, I advise to take a look at the Vivitek Qumi Q6 measurement tests it has some surprising strengths, but there are also some nuances, about which it is better to know in advance.

A primer explaining how to get the most out of graphics for the most savvy users can read

here

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Vivitek Qumi Q6 projector

The Vivitek Qumi Q6 was tested in a professional studio in a totally darkroom with neutral walls, where it is almost impossible to distort colors. The projector was clearly set up for the Da-lite screen – exactly centered, which was used to display the test image of size 1.5m on the larger side.

Measured with an X-Rite i1Display Pro colorimeter. HCFR Colorimeter 3 is the software of choice.1.0.6. This program understands the correction profiles supplied by the manufacturer and spectral correction profiles designed to increase accuracy

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By correcting the measurement results depending on the type of backlighting of the display device CRT, CCFL, W-LED, Wide Gamut, Projector, etc. .

The CIE76(ab formula is used to determine the color deviation dE .

We have tested all modes available on the projector.

We were interested in the main parameters that affect image quality:

• Evenness of screen illumination
• Color gamut
• Contrast
• Gamma Curve
• Grayscale
• Color accuracy
• Color temperature stability

Let’s start with the CIE charts, which allow us to evaluate the color gamut, and give a general idea of the color temperature and the presence of color casts.

The color gamut number of colors reproduced of the projector itself is great, but the color triangle is biased toward red and green. As a result, the projector lost somewhat in the blue-green RGB zone.

I would probably most often use the TV, Personal and Movie modes with this projector: the blue-mauve-red color boundary is almost identical to the reference line, providing the most natural color reproduction. In other modes, this area of the color wheel is displayed more saturated, which results in a thickening of the colors.

Now to color temperature stability and parasitic tints.

Many modes are similar to each other. For example, the Film and Personal modes tend to have stable cool colors and are practically devoid of parasitic tints. You can easily draw such a conclusion by looking at the almost identical distribution of pixels in the grayscale area. They are fairly clustered near the cold side of the dE=10 confidence interval. The vast majority of dots are located on the curve, which indicates the absence of parasitic tones.

So you don’t have to worry – the gray asphalt will stay gray on the screen, and not turn into greenish or lilac hues.

In Bright mode, we see a shift of dots to an area with minimal green parasitic tint, which is the only mode with a warm color temperature.

Game mode is traditionally a very cool 9,400K color temperature, although it is stable throughout the brightness… I think that those who play Quake in this mode and roam around damp basements will feel hot and cold from cold colors – they are not busy looking at love in ripe rye..

In Presentation mode, the color temperature is also cool, but the spread of gray wedge points is slightly shifted to blue – it’s a slight parasitic tint. But there’s nothing wrong with that. We’re used to the text on the “white” paper, which is actually bluish, but the real white at D65 is much more yellow. That’s why the text on the bluish background is perceived with flying colors.

In the sRGB mode, on the other hand, the color temperature is so cold that the curve doesn’t even have any bars and you can see an obvious extraneous blue-and-lilac tint. However, sRGB mode is designed not for movies, but to work with a PC as a monitor, where the hue does not play a noticeable role..

TV mode also gives us a cooler color temperature, but a bit warmer than in Game and Presentation modes. There are practically no extraneous shades. So the image is quite acceptable, I would compare it by color temperature to an inexpensive laptop monitor, which often make a mistake with cold tones.

The final mode is Personal1. Yes, the color temperature is about 6500K, but it is accompanied by a clear parasitic lilac hue. Of course, we won’t make a tragedy out of this result: the Personal1 mode was specially added to calibrate it according to all the rules of “martial arts”. And the factory defaults do not have to be a copy of the standard.

Color temperature

Throughout the medium and light tones, the color temperature in all modes is fairly stable, but in the shadows everywhere, except in Bright mode, there is an excessive coolness.

The color temperature in Film and Personal modes is almost identical and is about 7750K, which is more by 1250K than the reference.This difference in temperature is noticeable to the trained eye, most viewers will take this “cooled down” picture as proper.

The color temperature of Personal1 is close to the reference, but by default it has some parasitic color shading, so it is best to use this mode after calibration.

Bright mode is the only one without cool shadows and the only one without warm shadows – its color temperature is about 5250K. Retro content will thank the projector.

In Play mode, the color temperature is about 9600K, which would surely be appropriate in the cold realm of the Snow Queen.

TV and Presentation modes are like twin siblings: TV has 8250K color temperature and the other has 8750K, the difference is a cooler picture in Presentation mode.

Before we go to the charts, I note that we estimate the color temperature, which shows quite a certain type of LEDs, seasoned with the shortcomings of a single-chip video projector technology.

Gamma Curves

Channel gamma curves open a series of measurements, which can be used to judge not only the color, but also the brightness, contrast and accuracy of tone transitions. Very interesting results for a handheld device.

In a number of modes – Game, TV, Personal, Film, channel gamma curves do not have noticeable stratification and go almost along the reference curve gamma 2.2. That is, halftone transitions will be clear, even color gradients should be reproduced without bands. I didn’t expect such a result from such an inexpensive device.

Personal1 mode clearly has a higher gamma value. And in this case the channels have no stratification, and the high gamma value improves the readability of the text in bright light: in this gamma the dark becomes even darker, making the black text stand out from the light background.

There is a similar story in the Bright mode, but you can see the stratification of the channels there. I don’t think this will seriously affect the perception of the image, but the layering can be critical if different details need to be clearly conveyed on the screen.

The channels behave differently in Presentation mode. The blue channel is at the level of the nearly perfect reference, while the green channel is noticeably higher and the red channel is obviously lower. If you suddenly feel like watching a movie in this mode, the colors on the screen will not be perfect. However, Presentation mode is not a movie reference, but an author’s preset from Vivitek designed to clearly display diagrams, charts, text slogans and explanatory slides.

In sRGB mode, while the brightness level is less than 50 percent, the picture is quite good. At higher brightness, however, the blue and green channels drift apart: first they return to the reference, then they fall lower again. Don’t think, you won’t see streaks or any other artifacts on the image. But the episodes with different brightness will have different shades of white.

Gamma

Gamma measurements are known to determine how adequate the contrast is at different brightness levels. When I looked at the graphs I thought at first that I opened a measurement folder of some Hi End projector. It doesn’t. The folder turned out to be the right one.

In Film, Game, TV and Personal modes the gamma value is very close to the reference 2.2, which allows you to get an accurate rendering of the brightness and contrast of the image. I’ll only note the slight sagging down in the darkest areas and up in the brightest areas. This means that the deepest shadows will be slightly lighter, and the brightest areas will be slightly darker.

The picture is somewhat different in the Personal1 mode. The transition between the two areas may not look very natural. Bright areas become darker and dark areas become lighter. And the transition area noticeably loses contrast. A similar case occurred in the Bright mode, only on a larger scale. The shadows in it start with a gamma of 2.05, and in the bright areas the gamma value reaches 2.6, so the image does not look very natural.

The gamma in sRGB mode tries to mimic the color space of the same name. In principle, this is how it turns out – except for small fluctuations of plus or minus 0.5 and slightly lightened shadows due to the value of 2.05 . On the whole, from the gamma point of view, sRGB mode is fine. However, let’s not forget that this mode has an extraneous hue and a cold color temperature..

And finally, mode Presentation. One of the few that offer us a lower gamma value – a brighter picture. The gamma value in the shadows is 1.95, and the average of the midtones and highlights is also underestimated – about 2.15. So, the Presentation mode is quite good for rendering the contrast details.

RGB levels

The RGB color gamut charts show if there is any gray area and at what brightness. The neutrality of grayscale is worth paying close attention to, because color distortions in them are much more clearly defined than in color areas.

The reason is banal – we know or guess which area should be neutral. If an extraneous hue is seen there, it is immediately apparent. At the same time we can often not know for sure what the color should be, for example, the grass can be lush green in spring and blooming green at the end of summer

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a little bit of a shriveled up. Without knowing the context of the episode, we take any shade of green for granted.

The projector shows stable color temperature results, so let’s pay attention not to RGB levels, but to the dE value.

Let’s start with the two winners, Film and Private modes. dE reaches 8. In the example of blue, the color difference from the reference looks something like this.

Recall that the value of dEMore than 10

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is the range in which, to the untutored eye, color deviations are almost imperceptible and in which we see an overabundance of blue levels. This makes sense, because these modes offer us a slightly cooler color temperature.

The Bright mode, the only one with a warm color temperature, has an overrated red channel and underrated blue one. Stability is quite high. The dE value is higher than 15, which means that color distortions will be noticeable to the eye. About right:

In sRGB mode the blue level is almost twice as high as it should be, hence the cool color temperature. And the dE value reaches 45. You can see for yourself how noticeable the color difference is.

Game and TV modes are similar in many ways, the only difference is that they have slightly different blue levels and, consequently, different dE. But this difference shouldn’t be taken seriously, since it’s only about the blue color and the cooler temperature, which our eye already perceives as native..

In the Personal1 mode, we observe a slight deficiency in the green channel, simultaneously with 115-125 percent levels of the blue and red channels. This combination of blue and red gives a lilac hue. This is what we get in the neutral areas of the image. dE is expectedly high

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about 18.

In Presentation mode, we can note the logical stratification of channels for cold temperature. The red channel level increases in the bright areas, which leads to a slight warming of the light areas of the image.

Additional characteristics and averages

	Contrast	Average Gamma	Average dE of grayscale	Average dE of primary and secondary colors	Approximate color temperature K
Game	713	2,18	13,95	15,80	9600
Presentation	726	2,12	9,87	52,98	8750
sRGB	449	2,21	29,55	52,85	?????
TV	710	2,18	9,76	15,04	8250
Bright	766	2,45	9,77	49,55	5250
Personal	730	2,18	5,23	14,47	7250
Personal1	735	2,35	11,75	47,59	6250
Film	713	2,18	5,22	14,60	7250

Additionally, let’s look at a number of other parameters, the most interesting of which is contrast. In our test, contrast is defined as the ratio of brightness of the white point to the black point, with measurements made on the reflected light flux from the screen. Obviously, in this case, the contrast depends on the area of the picture. For a screen of one and a half meters on the larger side , the projector gives us 730:1. That’s pretty good. Only in sRGB mode the contrast is only 450:1.

Gamma value in all modes of the projector also shows a decent level.

But looking at the dE of primary and secondary colors, we can note that all modes are divided into two groups. In the first

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Game, TV, Personal and Film modes with their ~15, and in the second

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The remaining modes in which the color deviations are up to 50.

Similar situation with the dE of grayscale. Although the difference between the groups is not so significant there, except for sRGB, where the dE of grayscale reaches 30.

Conclusions on modes

Film, Private are probably the most successful of the modes, we suggest they should be used everywhere as they provide the best color reproduction quality.

Game – fully lives up to its name. Great for games, and the lowered color temperature will only give game scenes an entourage and drive.

Presentation and TV are not bad modes if the user prefers cooler color temperatures. I wouldn’t recommend this mode if you want accurate halftones.

Bright, sRGB and Personal1 – in our opinion, these modes have no practical use and require serious correction. This is due to the gamma curves, and color temperature, and most importantly, the presence of parasitic shades.

Conclusions

It was hard to imagine that such a mini projector, always on hand, could compete with devices from the home theater segment. Decent image quality coupled with great connectivity and amazing mobility make the Vivitek Qumi Q6 an extremely attractive option in its consumer niche.

Several built-in modes are capable of delivering a decent level of color reproduction.

High brightness and good performance in high ambient light conditions.

The highest mobility.

Wide range of connectivity options including wireless .

No lens cover.

Some factory modes are hard to call perfectly tuned.

Not all menus are logical.