Projection Environment Conditions

[BarkingGhost]

Do you plan on or have already bought a front projector, AND based strongly on the purchase decision the advertised Contrast Ratio performance?

Simple On/Off Contrast Ratio is a measurement of peak white output in full field without blooming, divided by the measurement of lowest black output in full field without crushing.

For instance, an example would be a hypothetical projector can display a full-field peak white that isn't blooming of 1000 lumens, and its uncrushed lowest black light output is 1 lumen. 1,000 / 1 equals a 1,000:1 Contrast Ratio.

Now, my concern is let's say another hypothetical projector claims 10,000:1 Contrast Ratio. Without knowing what the non-blooming peak white or uncrushed black value was, it would be hard to know how the projector is actually performing.

Business projectors typically are used in working environments with a lot of ambient lighting measuring well into the hundreds or thousands of lumens. As such, a business projector typically doesn't care about the uncrushed black light output of a projector and focuses on the non-blooming peak white output.

On the other hand, in a home theater environment the typical working environment is usually light-controlled. I light controlled environment can be quite strong in its ability to control, or even eliminate, all light not coming from the projector itself.

As a result, a typical home theater projector needs to advertise its Contrast Ratio performance in terms of how well it can control light output when it is not wanted. For instance, a fade to black scene in a movie scene that was pretty dark already may lead to a 'black field' that is really more dark gray then true black.

The display technologies currently in production in mass market are all based on blocking, or hiding, light output from their respective light sources. Old technology like Cathode Ray Tube, and future technologies like SED/FED simply do not generate light when it is not called for.

Now imagine, a business projector will an uncrushed black level output of, say, 100 lumens to that of a home theater projector at 0.1 lumen. But the threshold in which the viewer determines his or her desired acceptance of what 'black' is can vary, both in general, and from movie scene to movie scene.

It is not uncommon, though, for manufacturers to make rather outrageous claims in the performance of On/Off Contrast ratios. Why is it so easy to make these virtual-lie claims? Because, most folks do not have access to, nor financial resources to accommodate the necessary equipment to measure the lowest light output from a projector.

Another hypothetical projector may be marketed as having 30,000:1 Contrast Ratio, but a peak, non-blooming white output of 750 lumens. This would mean the marketing is suggesting a uncrushed black light output of 750 / 30,000, or 0.025 lumens. But if you or I didn't have a means to measure that little of light then there would be no way to call the manufacturer out on it.

Now some would say they couldn't tell the difference between 1 and 0.025 lumens, and that may be the case. I could also suggest I couldn't tell the difference between 0.025 and 0.000001. But if I claimed my 750 lumen non-blooming peak output project had a Contrast Ratio of 750 Million to 1 how much worth or value would you place on the aspect of the projector?

First, since I do not know of any measuring device that can measure 1/1,000,000 lumens. As such, I can feel comfortable knowing no consumer can prove that I am lying in my market of Contrast Ratio. I could claim whatever I want, and many manufacturers do, and no consumer protection is there waiting to protect you, or me.

So keep this in mind what the store's little buddy tries to sell you on the more expensive or top of the line product when you may never get the actual performance in the first place. Also, and MORE importantly, what good is a projector capable of 0.025 lumens uncrushed black light output if your environment has 10 lumens of ambient lighting present?

[Disky76]

...but I will give it my best shot.

I got involved with FP about a year ago. I researched the FP world for several months before taking the plunge and purchasing my projector. I bought it sight unseen and, from the moment I set it up, have continued to be pleased with its performance.

I believe the HC-1600 operates with 1600 lumens and a 2500:1 contrast ratio. Bear in mind, my room has become a dedicated theatre that is in total blackness 24 hours a day unless the projector or lighting is turned on. The picture is very, very bright and sharp, and I keep the setting in low mode.

I don't know what a 30000:1 projector would look like in my theatre - because my projector is brighter and sharper than the local cinema.

Honestly, I would imagine that 30000:1 is a ratio that would be needed for a very, very large room with ambient lighting. Our projectors can project into theatres much larger than ours, therefore the projectors will most likely offer more than what we would ever need unless using the projector commercially.

I think my picture is about 18fL or so - and I believe if you go to the ProjectorCentral website and use their calculator, it will tell you how many fL you will be getting based on the variables that you enter into the calculator.

[BarkingGhost]

Originally Posted by Disky76

...but I will give it my best shot.

I got involved with FP about a year ago. I researched the FP world for several months before taking the plunge and purchasing my projector. I bought it sight unseen and, from the moment I set it up, have continued to be pleased with its performance.

I believe the HC-1600 operates with 1600 lumens and a 2500:1 contrast ratio. Bear in mind, my room has become a dedicated theatre that is in total blackness 24 hours a day unless the projector or lighting is turned on. The picture is very, very bright and sharp, and I keep the setting in low mode.

I don't know what a 30000:1 projector would look like in my theatre - because my projector is brighter and sharper than the local cinema.

Honestly, I would imagine that 30000:1 is a ratio that would be needed for a very, very large room with ambient lighting. Our projectors can project into theatres much larger than ours, therefore the projectors will most likely offer more than what we would ever need unless using the projector commercially.

I think my picture is about 18fL or so - and I believe if you go to the ProjectorCentral website and use their calculator, it will tell you how many fL you will be getting based on the variables that you enter into the calculator.

For digital projection, one seeks out peak ANSI lumens to overcome ambient lighting conditions. One focuses (no pun) on contrast ratio to achieve lower black levels in the projected image. You know, to see the detail in low-light scenes.

[victorvondoom88]

ANSI contrast measures the dynamic range potential in a given frame of video, or the actual difference between black and white at the same time. ANSI contrast numbers are always much lower than Full On/Full Off numbers, so they are not typically published in official specifications.

Full on/off measurements measure a full white screen vs. a full black screen. This is what manufacturers always use since it makes the product sound more impressive.
There are many other factors when it comes to projectors and contrast some have "dynamic" iris that open and shut rapidly during scenes to artificially boost contrast or perceived contrast. Some projectors however are poor at doing so and the image will look like the light it's pumping or fluctuating which can also be distracting. Kind of like the lights in a movie when someone is being electrocuted.

Here is a good read on why you cant rely on manufacturer specs

http://www.projectorcentral.com/contrast_ratios.htm

And here is a review that compares a new 200,000:1 Contrast ratio projector to the previous model 75,000:1 from the same manufacturer!

http://www.projectorcentral.com/epso...tor_review.htm

Excerpt from review

Contrast. Though 200,000:1 sounds like a huge increase in contrast over last year's 75.000:1, it really isn't. We are now into a range of high contrast performance where small changes in black level can have an enormous swing in the statistical measurements. It is easy to suppose that the 8500UB must be "more than double" the contrast of the 6500UB, and that sounds like a huge thing. What it actually means is that black, which was already quite black on the 6500UB, is a shade blacker on the 8500UB. The difference is noticeable in a very dark room, on images that are predominantly black, like rolling credits, or images of stars in the night sky. With this type of imagery, the 8500UB achieves a black that is unsurpassed in this price range.

The increase in contrast has been achieved with further refinement of the auto iris system. While this has a noteworthy effect on black levels and on/off contrast specs, it has less impact on visible contrast in most scenes with average light levels. In scenes of a sunny day, or characters talking in a restaurant, the 8500UB's actual improvement in contrast over its predecessor is marginal at best. In short, while there are several solid reasons to buy the 8500UB, the fact that it has a 200,000:1 contrast rating isn't one of the big ones.

And for the record I'm not saying either of these projectors is a bad one it just illustrates the fact you can't really rely on the specs.