Toshiba Regza 40XV645U

Black Level (9.11)

We measured the Toshiba Regza 40XV645U's black level at an impressive 0.06 candelas per meter squared (cd/m2), which is very good. This is significantly better than our average HDTV, and beats outall of our comparison models, although the Sony and Samsung come close to matching it. It far outmatches the JVC model, however.

Black Level

Peak Brightness (8.30)

We measured the Toshiba Regza 40XV645U's peak brightness at 298.86 cd/m2. Once again this is good performance, although not quite as impressive as the black level. Below you can see that it lags slightly behind our comparison televisions, but not by much, and it should be plenty bright for any situation.

Peak Brightness

Contrast (9.15)

As you might expect from the good black level and peak brightness the Toshiba Regza 40XV645U's contrast ratio is very good at 4981:1. You can see below that this compares favorably with the Sony and Samsung models, falling between the two, and is far better than the JVC model. Contrast ratio is important as the human eye is very sensitive to it.

Contrast

Tunnel Contrast (9.78)

In this test we check to make sure that the black level stays constant as progresively less black is displayed on the screen. The Toshiba Regza 40XV645U did very well in this test, with only minor fluctations in the black leve as we went from a 100% black screen to a 5% black screen. This is important because if the black level increases with smaller amounts of black on the screen you lose a lot of your contrast ratio in scenes with only small patches of dark areas. This won't be a problem with the 40XV645U.

Tunnel Contrast

White Falloff (9.98)

This is the opposite of the previous test, here we want to make sure the peak brightness doesn't vary as we reduce the amount of white on the screen. The Toshiba Regza 40XV645U once again performed admirably as the peak brightness stayed rock solid throughout.

White Falloff

Uniformity (5.50)

In this test we look at the uniformity of an all white and all black screen on the Toshiba Regza 40XV645U. With the all white screen things looked good, with just a small amount of dimming at the corners and along the edges. With the black screen, however, we noticed significant bright areas at the corners and also saw blotches of brighter areas across the center, which is worrisome as this can detract from the viewing experience when looking at darker scenes.

Greyscale Gamma (8.52)

We measured the Toshiba Regza 40XV645U's gamma curve at 2.45, which is close to our ideal of 2.1 to 2.2. This means the television should make correct adjustments as it goes from dark to light. Some HDTVs have a much higher gamma, which means the adjustments happen more aggressively and can cause you to lose detail in very dark and bright areas. This shouldn't be a problem with the 40XV645U.

Greyscale Gamma

Resolution Scaling (8.33)

Although the Toshiba Regza 40XV645U is capable of displaying full 1080p content, the reality is that the only place you'll get content at that quality is from a Blu-ray disc. Most of the content that you will get on your HDTV will come in one of the flavors listed below, and in this section we look at how well the HDTV handles these various formats.

480p (8.50)
This is the format used by standard definition television and DVDs. The Toshiba Regza 40XV645U's does a good job with 480p content, unlike most HDTVs we were able to adjust the view settings so there was no overscan, although in order to do this we did have to give up using the entire display to view the content, with black bars appearing on the left and right. If you stretch the content out there will be about a 3% overscan at the top and bottom. There were no serious problems with moire patterns, legibility or resolution.

720p (8.0)
This is the lowest quality of high definition content and is used on the internet and sometimes by broadcast HDTV sporting events. Once again we were able to get zero overscan, but we did start noticing some problems with moire patterns. In particular we noticed some fine patterns appearing in certain orientations of alternating black and white lines. This was the only significant issue we saw, however.

1080i (8.50)
This is the standard used for broadcast HD. Unlike 1080p content, however, it is sent in two sets of 540 lines rather than one set of 1080 lines. This reduces the bandwidth required, but can also introduce problems. Thankfully no major problems were present in our testing.

Compare the Toshiba Regza 40XV645U to other HDTVs
Sony KDL-46Z5100 46 inches	Samsung LN40B650 40 inches	JVC LT-42P300 42 inches