contrast ratio [Archive] - Audio & Video Forums

PDA

View Full Version : contrast ratio



pizzakid13
10-11-2005, 11:37 PM
while researching differnt LCD flat panels, i noticed that they all have different contrast ratios. some are 800:1 while others like the samsungs are 3000:1. how big a deal is this and would i notice the difference between 800:1 and 3000:1?

csukasem
10-12-2005, 05:02 AM
Hi,

I am using Denon A11(5900) + Marantz VP12S2(contrast ratio 2600:1). My room is "black". The only problem I have is black level; the darkest is still not solid black.
The good contrast ratio (to get real black), I heard, should be around 3500 - 4000:1.

I don't know if this information is applicable to you since my Marantz is DLP front projector, not LCD flat panel.

Sukasem

edtyct
10-12-2005, 05:57 AM
Contrast ratios in video are a little like power ratings in audio for receivers. Since there's no real standard, mfgrs can use whatever test gets their products a better number. The further problem is that you can't really tell which video test they used (though with a little investigating, you can make an educated guess). To be brief, they can measure contrast in a manner that takes advantage of a panel's high brightness levels at the expense of black levels, thereby achieving a high number that says nothing about how dark images can get in low-level light. I'm afraid that you'll have to throw out inflated contrast numbers and read reviews if you can find them. For LCD, keep your expectations low for black level, anyway, although they are getting more satisfactory with every iteration. If you can manage to do a comparison in the store with blank screens (with the panels powered up), the ones that show a neutral dark grey, or at least seem darker, probably have a better contrast on the dark side (not in the Star Wars sense) than those that are distinctly grey, have a hint of color about them (like dark green or purple), or look illuminated like the nightime city sky through a haze of street lights. This test will not mean, however, that the panel is better in other respects.

Ed

pizzakid13
10-12-2005, 09:34 AM
For LCD, keep your expectations low for black level, anyway, although they are getting more satisfactory with every iteration. If you can manage to do a comparison in the store with blank screens (with the panels powered up), the ones that show a neutral dark grey, or at least seem darker, probably have a better contrast on the dark side (not in the Star Wars sense) than those that are distinctly grey, have a hint of color about them (like dark green or purple), or look illuminated like the nightime city sky through a haze of street lights.

Ed
ok. blank screens with the panels powered up means looking at them turned on with no video signal?

edtyct
10-12-2005, 11:02 AM
I'm assuming that you won't have much control over what you see in the store. If you take a look at the panel powered up with no video signal, the screen will be brighter to some degree than the screen without power, which is how black should really look (true absence of light, as you'd get with a CRT). The difference between how the panel looks powered and unpowered is the amount of bleed from the bulb in the background, but it isn't easy to see when the lights are at full blast. The safest indication of how black a panel can get would come from a test disk played in a darkened room, but a black-oriented scene or white credits against a black background on a DVD would be good, too. A movie like Dark City, Woody Allen's Shadows and Fog, outer-space sci fi, or a 1940s film noir, will show no mercy on a panel's capacity to portray gradations of black. Also, some panels are better than others at holding a dark image that has to share a frame with something bright, even if they can manage a convincing black by themselves, and some are better than others at protecting the screen uniformly from stray light. Test screens come in handly, but unfortunately most people have already bought their TVs before they can run them. But remember that these issues aren't necessarily deal breakers. TVs have a lot of room to redeem themselves in other respects.

Ed

pizzakid13
10-12-2005, 03:54 PM
ok, i get it. so a dark showroom would be better for comparing LCDs. most stores are brightly lit which i assume makes the LCDs really pop.

edtyct
10-12-2005, 04:48 PM
Right. LCDs are the masters of the bright picture. If you were to do most of your watching in a well-lit room, LCD would be a great choice. Weak blacks don't look bad at all in that kind of environment. But I'm not being cavalier about LCDs. They can present terrific hi def pictures if they're set up correctly and are the right size for the viewing distance. For example, the 26" JVC is so bright and sharp that it looks almost three dimensional; its strong suit can offset its lack of color fidelity for a lot of people. You have to set your priorities, even if only while you're shopping, because every TV made has compromises. That Philips in your first post may well be a good choice, since it seems to cover every feature and ergonomic issue under the sun, but the Sharps also deserve a close look, as do others. You might do well to read a couple of professional reviews of panels on your short list to get a sense of what's at stake and follow where your research leads.

Ed

pizzakid13
10-12-2005, 11:11 PM
any other place than cnet to get professional reviews?

edtyct
10-13-2005, 04:00 AM
CNET has the advantage of being free, and UltimateAV, which has always had good reviewers is now free, too. The LCD Buying Guide is another good site. You might also try a google search on various panels and see what you turn up. Another option is to search at the AVSforum, which is bound to have some information. The more posts that a product accumulates there, the better are your chances to get a decent assessment, but you may have to wade through a lot of dross.

pizzakid13
10-13-2005, 01:32 PM
CNET has the advantage of being free, and UltimateAV, which has always had good reviewers is now free, too. The LCD Buying Guide is another good site. You might also try a google search on various panels and see what you turn up. Another option is to search at the AVSforum, which is bound to have some information. The more posts that a product accumulates there, the better are your chances to get a decent assessment, but you may have to wade through a lot of dross.
i have been at AVSforums and found some web sites but no actual forums. i assumed it was like this place. i will check out the other 2.

pizzakid13
10-13-2005, 06:01 PM
well, i looked at the LCDs in a darker store. it is very noticeable especially when placed next to a plasma.

edtyct
10-14-2005, 03:45 AM
AVS home page, on the left side, you'll see a column headed by "Enter Main Forums." Click and you'll see all of the possibilities. Scroll down the "Display Devices" section to "Plasma and Flat Panel LCDs." Once you enter that forum, you can run a search on particular panels, or look at the various threads. Make yourself comfortable; you may be there for a while. But do try the LCD Buying Guide, at least, to get a sense of what the strengths and weaknesses of flat panels are.

pizzakid13
10-14-2005, 01:08 PM
AVS home page, on the left side, you'll see a column headed by "Enter Main Forums." Click and you'll see all of the possibilities. Scroll down the "Display Devices" section to "Plasma and Flat Panel LCDs." Once you enter that forum, you can run a search on particular panels, or look at the various threads. Make yourself comfortable; you may be there for a while. But do try the LCD Buying Guide, at least, to get a sense of what the strengths and weaknesses of flat panels are.
ok. any reason i shouldn't be interested in a plasma?

edtyct
10-14-2005, 04:02 PM
Plasmas do some things better than LCDs, like show black, and are larger on average. The pixel count doesn't generally reach LCD levels, however, until the 50" size, though most people wouldn't know the diffference just by looking. However, those who use their TVs for games, watch 4:3 material with black bars on the sides--even when they have the option of removing them with a stretch mode--and/or insist on cranking up their contrast/brightness to dangerous levels, either out of preference or ignorance, might do well to avoid plasmas. Uneven wear on the screen, or burned logos and legends, are a reality with plasmas, though paranoia about them is unnecessary with a little caution, especially now that most of them incorporate some sort of protection. Panasonic and Pioneer plasmas are definitely worth a long look if you're going in that direction.

pizzakid13
10-15-2005, 12:51 PM
i did look yesterday and they are beautiful no doubt, but i am gonna get the bigger samsung DLP. save myself a grand.