[CINERAMAX]

What would be the relative merits of using these projectors with either iteration of the DNP optical rearscreen in sizes of 110" 16x9?

DNP Rearscreen - New wide angle. Look for Products then New Wide Angle

PDF New Wide Angle

 

[CINERAMAX]

nice..... writing to the blind.....

 

[JimmyR]

 I saw it but didn't know what to say.


Ok, isn't that material simalar to VuTec high gain SilverStar and Prismatec for rear view ?


Last I heard you were going to maybe beta the SilverStar and play with making it retractable. We heard nothing from YOU


I would like to hear much more Peter..

 

[CINERAMAX]

Jimmy, please welcome to the forum Mr. Henrik Mikkelsen of DNP, denmark.


I am sure Alan is going to get swamped for DNP rearscreen orders after Mr.Mikkelsen answers all your questions.

 

[MrWigggles]

I was very impressed with DNP screens last time I saw them at a tradeshow in 2001.


The interesting thing was they were mainly going after the comercial market with dual vision type screens and not home theater specific models. But at the time, I said to myself, "these would make some great home theater screens". Sounds like that is going to pan out for them.


Their stuff looked good back then and I'm sure it looks even better now.


-Mr. Wigggles

 

[noah katz]

Trouble is, a HT sized DNP screen will cost more (>$5K) than most people will pay for a pj.

 

[H. Mikkelsen]

The screen choice depends very much on the level of ambient light. The higher level of ambient light the higher demand to the screen’s ability to maintain the contrast level generated from the projector.


To help you choose the right screen I have calculated the output with the two different projectors based on a 110†16:9 screen.

The ambient light level used for the calculations is based on 30 Footcandle coming into the screen surface.


Screen: dnp New Wide Angle High Contrast

Projector: MarantzS2 (700 ANSI lumen / 2600:1 Contrast)


Result:

Display brightness: 21.34 Candela /ft2.

Display contrast: 36:1



Screen: dnp New Wide Angle High Contrast

Projector: Infocus 7200 (1000 ANSI lumen / 1400:1 Contrast)


Result:

Display brightness: 30.48 Candela /ft2.

Display contrast: 50:1


Please be aware that the contrast ratio stated from the projector manufactures is stated as “ Full on/off†contrast. The contrast level measured by the ANSI standard is typical much lower due to flare in the optical light path.


As the result show, the contrast ratio of the screen is of much bigger importance than the contrast ratio of the projector.


The dnp screen is based on optical lenses, which allow the light to be distributed in a controlled direction.

On the backside of the screen is a high precision Fresnel lens, which redirect the projected light and sends it forwards at a right-angle to the image forming element. This construction secures a very uniform brightness level on the whole screen surface.

If you use a plain diffusion screen the light will just pass trough the screen in the same angle as is enter into the screen. The light in the corners of the screen continues and eventually hit the floor or ceiling. (lost)


The resolution of the optical screen is very high. dnp has developed screens especially designed for single lens projectors, (No color correction needed) the pitch of the Fresnel lens is variation from 4.4mil to 9.8mil

For the Lenticular the dnp pitch range from 5.5mil (UCS) to 9.8mil (New Wide Angle)


The pitch of the Fresnel and the pitch of the Lenticular are carefully engineered based on our long experience from our consumer TV business. With the entire screen developed for single lens projectors you will never see any interference between the projectors LCD panel or the DLP’s mirrors.

 

[CINERAMAX]

Noah:


Just like we helped (to borrow Bretts term) democratise the TORUS screen, I have discussed with Henrik the potential of POWERBUY through Allan. The screen is the most overlooked component of home theater, if people , replace their expensive Audio Budgets with more cost effective DVD-Audio systems, that sound better on DVD-Audio, for 20,000 less, then they can truly have a wonderful home theater experience.


We seldom if ever used a regular front projection screen in our high end installs, we either used White Curved screens (Torus, Biener=rip) or DNP screens, there is no excuse to use these cheap screens, AFAIK. Too much is wasted.



Henrik:


For my calculations of TORUS screen image brightness compared to regular front projection screens we use Foot Lamberts instead of Candela per....



Assuming an ilumination in the room of 5 foot lamberts, what is the Foot lambert equivalent of the above numbers.

 

[noah katz]

Mr. Mikkelsen,


"If you use a plain diffusion screen the light will just pass trough the screen in the same angle as is enter into the screen."


Wouldn't this mean that there is no diffusion occurring?


Noah

 

[H. Mikkelsen]

5 Footlambert = 1.563408 Candela / ft²

1 Footlambert = 0.312682 Candela / ft²

1 Candela / ft² = 3.198141 Footlambert



For a good luminance/iluminance converter use the link below
http://www.onlineconversion.com/luminance.htm

 

[noah katz]

Peter,


As I alluded to in a related thread, I think what is needed is a diffusion screen with lenticulations. Most screen mfgr's say that a Fresnel element is needed only for throw ratios

 

[CINERAMAX]

340 foot lamberts. There is never too much light.


This is almost like a good plasma.

 

[H. Mikkelsen]

Noah,


The light will be diffused in a diffusion screen, but the major axis of light direction is still the same as if youre drawn a line from the projectors lens to the corner of the screen.

Compared to a screen with a Fresnel lens, you will independent of your viewing position always have a bigger deviation between the most bright area of the screen and the less bright area. Because the angle between your viewing angle, and the major axis of the projected light is bigger on a diffusion screen without a Fresnel.


All screen contain diffusion particles, whether the have a Fresnel or not, but the Optical screen has a much lower amount of diffusion material, because they use lenses to direct the light instead of the diffusion agent. This secures a better yield of the light, because the loss of light is limited in a lens compared to a diffusion particle. This allows us to concentrate the energy on the contrast enhancement.


dnp produce screens without Lenticular. The Alpha Screen has a Micro Filter inside the screen, very close to the fresnel, this secure a screen with the same contrast level as the New Wide Angle screen, but a better Vertical Viewing angle.

 

[CINERAMAX]

Henrik


One day later I find out that there is a new affordable 3chip dlp from Panasonic.


I would like to see your revised brightness and contrast numbers with the new panasonic 7600.

http://projectorcentral.com/news_story_464.htm

http://www.fowlerinc.com/catalog/pro...p?prod=ptd7600


Also since the projector is soo bright 2500 on a single lamp, for the 122 diagonal 16x9 NWA , then adding the anamorphic lense, what could be done to maximise black level, would the special 1.3 gain be more appropiate?


The anamorphic adapter probably would be the Professional 4:5 to 16:9 Panamorph, which reduces vertical height but leaves width intact.


Although that type of prism lens may not work with a short throw lense due to the wide angle. The problem with the isco is cost.

 

[H. Mikkelsen]

Peter

Here is the calculation based on a 122†16:9 screen.

The ambient light level used for the calculations is based on 30 Footcandle coming into the screen surface.


Screen: dnp New Wide Angle High Contrast Gain 3.5

Projector: Panasonic 7600 (5000 ANSI lumen / 600:1 Contrast)


Result:

Display brightness: 396.25 Footlambert

Display contrast: 62:1


Screen: dnp New Wide Angle High Contrast Gain 3.5

Projector: Panasonic 7600 (2500 ANSI lumen / 600:1 Contrast)


Result:

Display brightness: 198.13 Footlambert

Display contrast: 33:1


Screen: dnp New Wide Angle High Contrast Gain 1.3

Projector: Panasonic 7600 (5000 ANSI lumen / 600:1 Contrast)


Result:

Display brightness: 147.18 Footlambert

Display contrast: 36:1