The benchmark: Sony VPL-HW40ES projector can safely go up in price

– REVIEW-VISUAL TEST

I have been told many times that emotions cannot be trusted. You have to measure seven times and pay once. Especially when it comes to a premium cinema projector like the Sony VPL-HW40ES. I can’t hide it, the image we see on the screen and very low price dispose to buying euphoria, but what will the unbiased figures show us in real life?

We would like to thank Dmitry Gusev, head of Digital Systems Ltd. department, for his help in setting up the test.

Test methods

This time we tested Sony VPL-HW40ES projector in professional studio, in absolutely dark room, with neutral walls, where the color distortion is practically excluded. The projector was clearly set to the Cima by Stewart 135″ screen – exactly centered, which was used to display the 313×180 cm test image. Distance to the screen – five meters. Measured with an X-Rite i1Display Pro colorimeter.

The software chosen was the freeware HCFR Colorimeter 3.1.0.6. This program understands the correction profiles supplied by the colorimeter manufacturer.Spectral correction profiles are designed to increase measurement accuracy by correcting measurement results depending on the type of backlighting of the display device CRT, CCFL, W-LED, Wide Gamut, Projector, etc. .

In our case, the only choice is the profile designed to measure projectors. Eight main modes and one user mode were selected for testing: Movie1, Movie2, Sample, TV, Photo, Game, Bright TV, Bright Movie, Sample calibrated. We were interested in the main parameters that affect picture quality:

• Uniformity of screen illumination
• Color gamut
• Contrast
• Gamma curve
• Grayscale
• Color fidelity
• Color Temperature Stability

Brightness by image field

For starters we decided to warm up with a Testo 540 luxmeter in hand. There are several methods to calculate the average illuminance uniformity of the screen. We decided to do the usual measurements without calculating the “average temperature in the hospital”.

The red dots in the picture show the places where the illuminance was measured with the luxmeter. A white image of 255R, 255G, 255B was displayed beforehand.

The brightest point of the image, the center, was taken as 100% and the rest were measured as a percentage of it. In order to color the image squares, the color was chosen as follows: 255R, 255G, 255B * percent relative to the brightest point, rounded according to the rules of mathematics. For example, a value of 81.4 percent corresponds to colors 208R, 208G, 208B in RGB space or simply 208 in GrayScale space.

The measurements were taken in the most extreme points having the least illumination. Although visually it appears that the differences between the squares are significant, in the actual image this is not the case.

As proof, let me give you this fact: the professional monitor NEC MultiSync PA302W, designed for serious work with graphics, the maximum deviation from the center point is 19 percent. Our test subject had 20 percent. The uniformity of illumination is almost professional.

Color gamut: going beyond sRGB – good or bad?

Now let’s move on to the measurements obtained by the colorimeter. Let’s start with the color gamut. Having opened the file, the first thing that came to mind was “these are exactly the measurements of our projector?!”. To my surprise, the color gamut covered almost the entire sRGB gray triangle space, which is the reference reference space, with a margin.

Color gamut in the presented modes exceeds the sRGB space gray triangle

In these modes, the color gamut is artificially reduced to match sRGB

– turn on the slide show

A truly outstanding result, which, however, carries a certain amount of danger and potential discomfort. In terms of color gamut, all projector modes can be divided into two groups:

1. Movie 1 and 2, Game, Brightness modes.TV and stretch TV – color gamut goes well beyond sRGB in greens and reds.
2. Sample mode, Photo mode – here, I believe, the color gamut is artificially reduced to match sRGB.

Why would the manufacturer reduce the color gamut, especially for the base mode Sample? There is a logic to this.

Suppose we want to show red color on the screen “in coordinates” 255R 0G 0B. But “red” is an abstract concept, it’s not a centimeter or a kilogram, red roses and a red flag will be red in their own way, with their own hues.

To define the red or blue, or green reference and its possible shades, color spaces have been invented which stipulate that the correct red and other base colors is the one with 255R 0G 0B coordinates in sRGB

In case of Sony VPL-HW40ES projector the red will be much redder than it should be in almost any mode. What’s the danger?? And by the fact that all the palefaces will be red as Indians – you could light up, and it would be as if all the green of the country had been poured on the foliage in the neighboring grove.

So the decision to slightly decrease color gamut in the Sample and especially the Photo modes looks quite reasonable. Moreover the gamut is not simply reduced, but brought in correspondence to standard sRGB that allows showing colors which are closest to reality without distorting what the photographer or director of the film had in mind with allowance for roughness of digital color reproduction .

However, all of this is true if the projector does not have the x.v.Color . In that case, the projector will still have the standard sRGB color gamut. If the function x.v.Color activated, an updated, wider color space comes into play, based on xvYCC parameters, which was developed as an international performance standard for video signals with an expanded gamut.

With a function of x.v.Color gamut will no longer be unauthorized outside the extended color triangle. As the diagrams show, the function x.v.Color just needs to be turned on in bright modes where the color gamut has “run out” of the old standard. As a result the colors on the screen will hold true, with the same grayscale tones even in a sunny living room, but in the familiar darkness of a movie theater the image will have new, subtler tones.

After the projector calibration the color gamut practically coincided with sRGB space.

Grayscale: Stray tones will be noticed

The color gamut charts also make it possible to preview the presence of parasitic tones in the image and the color temperature. If the points of the gray wedge have the smallest spread, you can talk about color temperature stability throughout the luminosity.

If these points “glide” along the black curve, it means that the image has a near perfect color temperature, matching the D65 reference 6500K . So the curve shift is not so terrible, and sometimes it is even intended.

If the points of the gray wedge “fly off” the black curve in either direction it means that there is a parasitic tint tint color according to the CIE chart .

In all modes, the points of the gray wedge went beyond the ring corresponding to dE=10. And in all modes there is a displacement of points relative to the black curve. In most cases, the diagram shows the gravitation of the image towards blue and mauve Film 1 and 2, Sample, TV, Bright.TV . The dot spread is relatively low, concentrated in the area corresponding to dE=15. Quite a decent result.

This time we decided to calibrate one of the projector’s modes to see how accurate it can be. As a basis we took the Sample mode. The result is shown in the last diagram.

Impressive, isn’t it?? All points of the gray wedge except one corresponding to 0% lightness fell within the confidence interval dE=3 and exactly along the black curve. As a consequence, in the calibrated mode we can guarantee a stable and accurate color temperature!

Color temperature: what’s better when it’s warm or cold?

The presented charts allow us to evaluate the color temperature in more detail when we change luminance, but unlike the previous charts do not give us an idea of the presence of hues. None of the modes showed a perfect color temperature. Deviations can be divided into two groups:

Modes,

Which color temperature

Shifted to the cold zone

: Sample – 6900K, Movie 1 – 7000K, TV – 6900K, Game – 7700K, Bright Movie – 8400K and Bright TV – 8400K.

Modes with color temperature shifted to the warm zone: Movie 2 – 5800K, Photo – 5800K.

All modes showed a relatively low cold temperature in the shadows. We can also note the interesting cooling of the color temperature at the lightness level of 40%. In general, the color temperature is fairly stable throughout the lightness level in all modes. A slight coolness in the shadows is hardly noticeable in practice.

After calibrating the projector, the color temperature stability is described as perfect.

Channel gamma curves: to be or not to be like a buck?

Now let’s look at the gamma curves, which show how clearly color shades will be distinguishable on the screen at different brightness. What these gamma curves are and what significance they have for quality image evaluation on all household devices, from tablets and smartphones to TVs and projectors, we’ve already covered in detail in a separate publication. You can refresh your memory of the main events of the “previous series” by following this link – Gamma Curve.

All profiles are clearly divided into two groups:

Relatively correct curves were obtained in the Kinofilm2, TV, Photo, Sample and Calibrated Sample modes.

Gamma rises slightly above the reference reference value in the midtones. But on the light and dark edges it’s almost the ideal value. Gamma channel decay is also not very high, indicating slight color variations in these modes.

The curved S-shaped gamma curves are clearly visible in Movie1, Bright Movie, Yaki TV, and Game modes.

This kind of deviation is very familiar to those who process photographs: as brightness increases, halftones become fewer and contrast increases in all components of the gamma. A simple rule: the steeper the curve, the higher the contrast, in a sunny living room you can choose the projection mode which best preserves the colors on an overly bright screen.

And vice versa: the image, which falls on the gentle parts of the curves or on the descending parts after the curve bend, becomes less contrasty.

Gamma Curves Playing with Light and Shadows

Now let’s try to see with our own eyes how different gamma curves change color rendering of the same image. To do this, take a picture with standard gamma 2.2. Let’s apply a false profile to bring the color rendition in this picture to Linear Gamma 1.0, i.e. zero gamma. Then let’s change the color rendering so that the gamma curve coincides with the averaged gamma of the Bright Film mode. Now let’s put all three variants one after another and feel the difference.

See how much more expressive the field has become with the S-gamma, and the image as a whole has become brighter there’s a reason the mode is called “Vivid Film” . But you always have to pay for fun. The sunset area with S-gamma has become almost flat, without details, as well as some clouds – especially it is clearly visible in the background of Gamma 2 image.2. S-curve kills the bright areas at the root, just burning them out, bringing them closer to the white spot.

Device: Nikon D7000, Lens: 24-70mm f/2.8G, Focal Length: 24 mm, Focus Mode: AF-S, AF-Area Mode: Single, Exposure Aperture: f/9, Shutter Speed: 1/10 sec, Exposure Comp.: 0EV, Metering: Matrix, ISO Sensitivity: ISO 100.

With our particular shot, the comparative effect of the three gammas cannot be called strictly negative, there are positive aspects: we lost details but increased the brightness for a daytime session. However, in other shots you can lose more than you gain. Take a look at the following image with the daisy. The S-curve completely killed all the detail on the petals, droplet veins, etc.d.

Device: Nikon D90, Lens: VR 105mm f/2.8G, Focal Length: 105 mm, Focus Mode: Manual, AF-Area Mode: Single, VR: ON, Exposure Aperture: f/13, Shutter Speed: 1/200 sec, Exposure Mode: Aperture Priority, Exposure Comp.: +1.0EV, Metering: Matrix, ISO Sensitivity: ISO 400

Why, then, did the factory settings use “scorching” S-gamma? The answer is quite simple: in bright daylight, which is known to kill the contrast and color fidelity in the projection of light colors, it makes sense to sacrifice the already grated parameters, but to add brightness and make the middle tones more contrast and vivid.

This is probably the main purpose of Bright Film and Bright TV modes – it’s the answer to “Chamberlain” in a sunny living room. But why the S-curve covered the Game mode is a mystery to me.

After calibrating the projector, it still failed to fit all the curves into the reference values. To tell the truth, we managed to noticeably decrease the spread between color gamma channels. So, the calibrated gamma curves became much closer to the reference curves than the original.

How gamma curves merge?

Let’s see how the gamma value formed by the curves described above changes. Although the ideal gamma value is 2.2, almost all modes contain an undervalued gamma. Moreover, gamma curves of some modes are not different at all. For example Photo and TV modes have absolutely the same shape of graph, only gamma level is different. And the Sample and Photo modes don’t differ at all in terms of gamma levels.

In the first pool of graphs, we’ve assembled the modes that show gamma reduction in the lighter areas of the image

The second pool of graphs contains modes that show a complete absence of gamma in light tones – it simply goes out of bounds

Gamma values in the shadows are close to ideal in all modes, but become smaller and smaller as the image gets lighter. In the modes with S-gamma, the gamma value in the light parts of the frame is out of the frame borders at all. We showed what this means in the picture with the fog on the field: the light halftones just disappear.

Even after calibration, it was not possible to achieve perfect gamut across the entire range from shadows to highlights. A slight dip in the graphs between 50 and 80 percent is still much better than what happens in the factory profiles.

RGB levels – Perfect calibration is not only possible on the monitor!

RGB levels are one of the main tools for color calibration. Ideally, the channel values should be identical and at 100 percent. In this case, the grayscale will be neutral and the color calibration will be fine. You can judge the presence of a specific grayscale tint by the deviation of the graphs from 100 percent.

Since these graphs illustrate the shift of gray wedge points both on and off the curve, the excess blue channel will be characteristic of cool modes and the red channel will be characteristic of warm modes. With the exception of the Bright and Play modes, all channels are reasonably stable at around 10 percent. This is a reasonably good, although not perfect, result.

What it gives? Let’s explain by example. If you have an image of a wall with grayscale ranging from black all in shadow to almost white where the sun shines , a neutral grayscale ensures that the dark part of the wall will not go to red tones, and the light part will not go to green. Or vice versa. If a tint does appear, it will be about the same on the whole wall.

As in other measurements, in RGB levels some modes completely overlap each other. For example Sample and TV, Bright Film and Bright TV.

Note the pink curve, that’s dE. Note that for the “bright” modes, the dE scale was increased because the graph went beyond the limits of the standard scale to dE=8.

The lowest dE is in the Photo and Movie mode2. Moreover, there is no tendency for the deviation to grow with increasing illumination, as in other modes. Note that the graphs of these modes are identical in general.

After calibration the RGB levels are 100 percent +/-2 percent, which is a brilliant result!

The mystery of projection modes

Now I would like to uncover the mystery of why some projector modes are so similar to each other.

Let’s remember that the Photo and Cinema2 modes have a lot in common: the same RGB levels, the same gamma throughout the lightness, the same color temperature… But what is the difference? In the name? There is only one parameter that is different between them: color gamut.

And there are a lot of such examples: the projection modes are identical in many measurements and differ in only one parameter, and not in a random parameter, but in one of the other modes.

You can guess how Sony configured the primary modes? This is called the faceted classification method – based on color gamut, gamma curve shape and color temperature.

Graphically, such a setup can be represented as a three-dimensional coordinate system.

You can clearly see what each mode is. For example, the “bright” modes, Game and Movie1 are just color temperature gradations.

Photo and Movie1 modes have different color coverage. The Sample and Photo modes are based on color temperature, and the TV and Cinema1 modes, apart from a slight difference in coverage, differ from each other in the shape of the gamma curve.

Did Sony engineers do the right thing? They simply went through the possible variations of similar settings, and refused to create unique profiles. I like this approach. For example, switching from Sample to Photo mode will only be accompanied by changes in color temperature and nothing else except micro changes .

It is convenient when only one parameter changes: gamma does not suffer, color gamut and other parameters do not suffer. We can easily adjust to our surroundings and lighting.

The table brings us to the end of the line

Contrast, a favorite parameter, was up to par in all modes. But, as one would expect, the contrast enhancement inevitably lowers the quality of the image, or rather, deviates it from the reference. The contrast is higher in modes with S-gamma, and you can see what it leads to in the example of a daisy: the white petals lose their veins and other details. True, there is no visual difference in contrast between modes only Game mode, with its 8000:1, stands out from the rest.

The average gamma values for all the modes correspond to their shape: normal shape – close to standard 2.2, modes with the S-curve have an inflated average value, especially for the Bright Movie mode.

As it turned out, the dE deviation of grayscale does not depend on the gamma curve shape and varies from 4.3 to 7.1 except for “bright” modes , which in general is very good.

With dE primary and secondary colors, the situation is already different. Not much to say about the “bright modes”, you can only dream about the color fidelity here. In addition to the shape of the gamma curve, color gamut probably also plays a role. The bigger it is, the less accurate the colors are.

Only two modes, Sample and Photo, have relatively accurate color reproduction. So if you don’t mind the tendency towards warmth, the Photo mode is the best choice if you want accurate rendition of shades and colors.

In other modes, the dE is in the 16-19 range. Is it a lot or not? This is not much, not even a lot. To compare, I will cite the measuring results of one of quite popular laptops ASUS X550C.

Average dE of grayscale = 13.87 and total dE = 21.9. And this on the LCD of the computer, not on the projector, which by definition should be inferior to the “live” matrix. Visually, the difference in dE*76 ab remember, this is the formula we use = 24.23 looks like this

Let’s note the outstanding results of projector calibration in Sample mode. Think about the calibrated values. They meet the requirements for professional monitors for printers and photographers. I’ve never seen anything like this before!

Conclusions

There’s no two ways about it: you want a cinema projector? Don’t hesitate and take the Sony VPL-HW40ES. We checked all the parameters, no artifacts.

Excellent contrast, good shades, decent color rendering, high uniformity of illumination, and adequate factory modes, the names of which indicate when it is reasonable to use them. And calibrating one of the modes through a combination of “projector + colorimeter” gives just crystal-clear results of the image. Such high image quality is certainly worth its, what seems to me, undervalued hundred thousand Dollars.

Another question is whether you always need such a perfect picture? For presentations, normal home movies, and other mundane things, super-precision in color reproduction may be superfluous – cheaper models are not hard to find for such purposes.

But if you create a Hi-End home theater or work with color, or if you’re one of those who just always want the best, then this projector is definitely for you. Unless, of course, you’re absolutely sure you don’t want to pay over a million for a flagship Sony projector.