Sony X850E vs X900E: Different backlight type & resulting implications for the Picture Quality

The main difference between the X850E and X900E is their backlight type which is Edge LED on the X850E whereas the X900E has a Direct LED (Full-Array Local Dimming backlight in particular). In contrast, the X850E can only perform frame dimming with its Edge LED backlight. There are several implications for the picture quality emanating from the backlight type on the X850E vs X900E.

Screen uniformity: The X900E has the upper hand, but there is less of a difference with the two 65-inch class TVs than the 75-inch class models.

The full-array local dimming backlight makes the X900E less prone to exhibiting screen uniformity issues, such as uneven brightness distribution, in comparison to the X850E. However, it needs to be said that the difference between the X850E and X900E varies with the screen size due to the fact that the 65-inch and 75-inch class TVs don’t have the same type of panel. The 65-inch class X850E and X900E models utilize VA (Vertical Alignment) type whereas their 75-inch class X850E and X900E counterparts have an IPS type of panel. This is important because VA panels are less likely to exhibit backlight glow in comparison to IPS. In other words, the 65-inch XBR65X850E model, despite the lack of a full-array backlight, has a screen uniformity that is more or less comparable to the 65-inch XBR65X900E. However, when it comes to the 75-inch class, the omission of the Direct LED backlight with local dimming on the X850E is exacerbated by the IPS panel, thus the difference between the XBR75X850E and XBR75X900E is more pronounced than it’s on their 65-inch class counterparts, not least because it’s easier to notice any small imperfections with the uniformity when the screen size is bigger.

Black level improvement: The X900E’s local dimming is, unsurprisingly, more effective than the X850E’s frame dimming but may cause halos

The native black level on the X850E and X900E is in the same ballpark, provided TVs of identical size are compared because there is a difference between the 65-inch and the 75-inch class models, as previously mentioned. The use of a VA type of panel leads to the 65-inch class XBR65X850E and XBR65X900E having a very deep black level whereas the IPS panel on the 75-inch class XBR75X850E and XBR75X900E is able to provide only a moderate minimum luminance level. It needs to be said that the X900E is able to further improve the black level since it has local dimming, which is especially useful for the 75-inch class XBR75X900E model due to its lighter black level. The frame dimming on the X850E is not able to selectively dim the backlight in different areas of the screen, therefore no meaningful improvement of the black level can be achieved. Considering that with frame dimming both highlights and shadows are equally darkened, there is no change in the contrast ratio, or the perceived black level on the X850E. It should also be mentioned that the local dimming zones on the X900E are rather large (due to the relatively low count), meaning the X900E is not impervious to halos around bright objects, depending on the specific scene.

Peak brightness: The X900E is more suitable for high ambient light environments due to its higher peak brightness. However, the X850E can get relatively bright as well

The X900E’s ability to exert control on the light intensity in different zones of the screen is used not only for dimming the backlight but also for boosting it. The implication being that while the light output on the X850E remains constant irrespective of the APL (Average Picture Level) of content, the X900E is able to adjust the brightness according to the APL of content in order to achieve higher peak brightness in small areas of the screen than in full-field white. In other words, the X900E can get from approximately 1.5 times brighter than the X850E when displaying high APL content (e.g. hockey, skiing, etc.) up to 2 times brighter than the X850E when low to mid APL content is shown. Considering that most SDR content has low to mid APL, it’d be hard to ignore the X900E’s advantage in terms of overall brightness in comparison to the X850E. However, due to the fact that SDR content is typically mastered to 100cd/m2, which is easily achievable by both the X850E and X900E, the aforementioned advantage of the X900E over the X850E is applicable mainly to high ambient light environments where the X900E is better prepared to compensate for the excess of ambient light owing to its peak brightness level of up to 800cd/m2 (10% APL) whereas the X850E is able to achieve only up to 400cd/m2 with SDR content, regardless of the APL. As previously mentioned, the difference between the X850E and X900E is slightly less pronounced with high APL content, but the X900E still has the upper hand.

High Dynamic Range: The X900E keeps its brightness advantage over the X850E, thus is able to render HDR highlights more faithfully

The full screen brightness of the X850E and X900E is irrelevant for High Dynamic Range content because the goal of HDR is to expand the dynamic range between shadows and highlights rather than increasing the overall brightness of the image. In other words, peak brightness in small specular highlights on the X850E and X900E is of interest with HDR content. Although the X850E is able to reach a marginally higher peak brightness with HDR signal than SDR, the X900E renders HDR highlights approximately 2 times brighter than the X850E. Therefore, the picture quality with HDR content is better on the X900E vs X850E. It has to be said, though, that even the X900E cannot avoid tone-mapping since its peak brightness falls short of the 1,000cd/m2 some HDR10 content is mastered to. When the HDR10 content is mastered to 4,000cd/m2, however, both the X850E and X900E clip the brightest specular highlights. This is done in order to avoid darkening of mid-tones, which would be inevitable if they attempted to resolve detail up to 4,000cd/m2 due to the fact that the HDR10’s static metadata doesn’t differentiate between scenes with highlights and those without. In order to counteract the limitations of static metadata, both the X850E and X900E utilize Dynamic Contrast Enhancer for optimizing the HDR10 on a scene-by-scene basis. Unfortunately, neither the X850E nor the X900E supports Dolby Vision, which by deafault includes dynamic metadata that has been generated during post-production. Considering the two Sony TVs don’t have the X1 Extreme chip, they cannot be updated to support Dolby Vision in the future. When it comes to SDR to HDR upconvertion, the X850E and X900E have the Object-based HDR remaster technology applied across most picture presets for the purpose of analyzing objects individually, and optimizing the SDR picture to appear more like HDR.

Viewing angles: Mostly identical, provided the X850E and X900E in the same size class are compared

Although there is no significant difference in viewing angles when comparing X850E and X900E in the same size class, it should be mentioned that the 75-inch class XBR75X850E and XBR75X900E models, owing to their IPS panels, have wider viewing angles in comparison to their 65-inch counterparts. The 65-inch class XBR65X850E and XBR65X900E tend to exhibit raising black level and loss of color saturation even at a rather small off-axis angle. The brightness decrease, however, is not as dramatic, so it’s along the lines of how IPS performs, if not slightly better.

Color: Triluminos Display, Smooth Color Gradation (both the X850E and X900E)

The wide color gamut support on the X850E and X900E is possible thanks to the Triluminos Display technology they are equipped with. Although only HDR titles use wide color gamut: the DCI-P3 (within BT.2020 container) in particular, SDR content can also benefit from the spectrally optimized backlight in the Triluminos Display, especially considering that the X850E and X900E include tone-mapping alorithm for the purpose of preventing colors in SDR content, which uses the smaller BT.709 color gamut, from appearing oversaturated. The X850E and X900E have 10-bit panels, meaning they are capable of displaying over a billion color shades. Furthermore, the Super Bit Mapping technique is present on both the X850E and X900E for the purpose of providing smooth color gradation without any banding or contouring. This is achieved via processing 8-bit or 10-bit sources with 14-bit precision, so that quantization errors can be avoided.

Design: The stand is different

There is a slight variation in the table top stand that is supplied with the X850E and X900E. The former has a Dark Silver U Slate, and as the name suggests, the stand somewhat resembles the letter U. The X900E, on the other hand, includes a Dark Silver Slate stand that features a metal slate that is joined at an angle with the two rear support columns. Speaking of which, they can be used for routing cables through on both the X850E and X900E so that no cables are visible from the front. The frame color is black on both the X850E and X900E.

Inputs & Smart TV

The 4 HDMI inputs on the X850E and X900E have identical placement: 3 side and 1 rear. All 4 HDMI inputs are HDCP 2.2 compatible. The 3 USB ports on the X850E and X900E are side-facing. The Smart TV platform is Android TV on both Sony TVs.

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