# Ruby and Brightness

14005 Views 141 Replies 38 Participants Last post by  OzzieP
After testing a new Sony VPL-VW100, Darin and I came to these brightness calculations. This is only one unit and should only be used to estimate light output.

http://home.comcast.net/~tryghoff/Ruby.jpg

Testing:

Tested unit is â€œstockâ€ out of the box with no calibration.

Projector was measured from Minimum to Maximum throws in one foot increments from screen. Measurements confirmed the relationship in light output drop-off is linear. Tested unit was brand new with less than 100 hours on bulb. 100 IRE test pattern (full white) with Iris fully open.

http://home.comcast.net/~tryghoff/RubyLumens2.JPG

The graph below gives an idea of how many foot lamberts to expect off a Matte White (1 gain) 10 foot wide 16:9 screen. Bulb new and "broken in". Iris open (turned off) measures approximately 3000:1 on/off Contrast Ratio. Iris closed (turned on) measures approximately 5000:1 on/off Contrast Ratio. Dynamic Iris in auto can only be assumed.

30% brightness reduction is an assumption of light output from this style of xenon bulb after â€œbroken inâ€ or 300+ hours. This is an assumed brightness level from ~300 to ~1500 hours on the bulb.

Maximum throw = Far from screen

Minimum throw = Close to screen

Foot Lambert â€œBrightnessâ€ Calculations:
Lumens x Screen Gain / Square Feet of Screen = Foot Lamberts

http://home.comcast.net/~tryghoff/RubyMatteWhite2.JPG

The graph below gives an idea of how many foot lamberts to expect off a Da-Light High Power (2.8 gain) 10 foot wide 16:9 screen. Bulb new and "broken in". Iris open (turned off) measures approximately 3000:1 on/off Contrast Ratio. Iris closed (turned on) measures approximately 5000:1 on/off Contrast Ratio. Dynamic Iris in auto can only be assumed. These calculations only give you an idea of the approximate foot lambert brightness if you are within the optimal viewing cone for the High Power (within a 5 degree angle of the projected image).

http://home.comcast.net/~tryghoff/RubyHighPower2.JPG

Reminder: These are optimal brightness measurements. Calibration of units, bulb usage etc. can all reduce these numbers. Sitting outside the optimal viewing angles for these two screens can also reduce these numbers!
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Thanks Darin for hosting me for Ruby viewing! Simply a stunning projector. The best that digital projectors have to offer from what I've seen. Amazing image!

For those wondering how far your projector needs to be from the screen to be within the "throw ratio". I made this graph of Minimum and Maximum distances. Closer to the Minimum distance the brighter the image.

All you need to know is how wide you want your image

http://home.comcast.net/~tryghoff/RubyThrowRatio.JPG
Fantastic work Tryg! No kidding. This will help a lot of people.

I can now sleep soundly, knowing everything will be fine.
Tryg,

What are the actual distances for min and max throws?
Thanx Tryg,

Any chance to hear a more in depth review on what you saw from the Ruby?

What did you think of the DI?

Black level?

How did it compare to other stuff you saw at Darin's?

Thanx

Ran
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Quote:
 Originally Posted by kraigk Tryg, What are the actual distances for min and max throws?
Now included in above graphs

Now, i'm headin over to Costco to see if they have Ruby's yet

I'll write a review of my impressions later. I still need to organize my thoughts. Basically it's the best digital projector I've seen. Darin and I compared it to his specially modified Optima H79 (9000:1) last night. The image of the Ruby was of course was much much brighter. The 3 dimensionality of the Ruby image was in another league. The Optima was indeed impressive (probably the best on/off and ansi CR of any DLP in the nation/world). But the dimensionality and depth of the Ruby image was simply stunning. more to come...
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With regard to the brightness measurements; what is considered the lowest acceptable levels in a light controlled room?
Brightness is relative. Light controlled room is relative.

All I know is I haven't seen an extremely bright image I didn't like. Brightness is VERY seductive. But with extreme brightness there can also be issues. Many projectors can hide flaws in the projector and source material by being dim. This can be good, and bad.

Theaters are usually about 12-16 foot lamberts

Direct view CRT TVs are about 40-50 foot lamberts.

Plasmas are as high as 50-70 foot lamberts.

Also, most dont have a clue what their projector really produce for lumens. Specifications from the manufacturers are poor representations of real world lumen output.

I prefer and recommend anything over 20 foot lamberts. 30 and above simply looks mind blowing if done properly.

Let me also couch this with "it depends on your seating distance". Generally the further you sit from the screen the more you will enjoy more brightness. Closer to the screen may feel annoyed by too much brightness in addition to the additional artifacts that may be visable.

Give me 30 or more!
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Tryg

I have read a couple of tv reviews in WSR. Both plasma and crt about 35-45fL when calibrated.
Tryg,

In my theater my seating distance is about 12' for a 110" diagonal Stewart Studiotek screen. I am considering replacing my Sony 10HT with a Ruby and, possibly, increasing the size of the screen to 120". I am trying to figure out whether the Ruby will be bright enough?

My current 10HT has been tweaked with "Smart" and consequently has a 30CC filter. Still, it's brightness is OK (although getting somewhat dim with 1500 hours on the bulb).
Well you came to the right thread! Seriously though read screen reviews below and understand what brightness is best for you. I imagine anything you're buy is gonna be brighter than what you are describing.
Quote:
 Originally Posted by Ohlson Tryg I have read a couple of tv reviews in WSR. Both plasma and crt about 35-45fL when calibrated.
Yeah, I was wondering about this too. I view often view movies on my plasma with the lights out and feel fairly comfortable doing so (it's calibrated). Actually, the last time I demoed the Ruby on that high-gain screen I sometimes felt like squinting (I'd zoomed the image to a 92" diag).
We watched the Ruby at near 45 foot lamberts last night(10 foot high power). I was in heaven
We watched the Ruby at near 45 foot lamberts last night(10 foot high power). I was in heaven
Tryg,

I read your 'White, Grey, or Silver' article and was wondering about your thoughts of pairing the Silverstar with the Ruby now that you have seen the Ruby.

Thanks,

Duane
I recommend it. Although the largest Silverstar you can get is 123" diag.

This is what I use. It's my favorite high gain angular reflective screen.
Quote:
 Originally Posted by Tryg We watched the Ruby at near 45 foot lamberts last night(10 foot high power). I was in heaven
Wow, I was watching "Earth, Sunrise" and almost got a sunburn, using a 15 ft. wide ultra gain silverstar and I was to close to the "cone of instant blindness" when the sun came up! Thank GOD for the DI, it save my irises from bursting into flames! It was almost like having LASIK! What's really weird is when watching "Earth, Twlight" it never got dark......but it did look almost 3D
Quote:
 Originally Posted by Tryg I recommend it. Although the largest Silverstar you can get is 123" diag. This is what I use. It's my favorite high gain angular reflective screen.

Thanks. My seating would be eleven feet. So I was thinking something in the 100-108" diagonal range.

Duane
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Tryg,

Those are amazingly straight lines. One rarely gets such perfection in the real world. Just out of curiosity, how many data points did you take for each line?
thats more or less what i found and post on the "my ruby test at home" thread

in the early beginning on page 2 or 3.

the biggest picture you can adjust 652 lux. Compared to the

maximum tele position (the smallest picture you can adjust) one loses more

than 40% of the light 368lux.
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