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Discussion Starter · #1 ·
Well, after finally getting everything set up to calibrate, I proceeded to start CalMAN and was stopped at my first step--contrast. After seeing numerous references to 30-40 ftl for a rear projection here in AVS forum, I was unable to find anything in CalMAN that mentions ftl except for the advanced description of contrast, which is just text, and says as an alternate method, get 30-40 ftl (but, doesn't tell you how to do it in CalMAN).


So, after spending a couples of hours searching everywhere for an answer, I gave up, and here I am.


How do I use my chroma 5 to set contrast in CalMAN (looking for ftl or a figure I can convert (need that formula, too))?
 

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In a calibration window, go to:

Options > User Interface > Units Standard


and change it from (cd/m^2 / Lux) Metric m^2 to (fL / fC) Imperial ft^2



I'm not quite sure why so many people here use fL instead of nits or cd/m². Metric seems a lot more precise, and the ITU/EBU recommendations for video white are 80cd/m² for monitors, 40cd/m² for projectors. (23.35fL, 11.67fL)
 

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Discussion Starter · #5 ·

Quote:
Originally Posted by andrewfee /forum/post/16928691


In a calibration window, go to:

Options > User Interface > Units Standard


and change it from (cd/m^2 / Lux) Metric m^2 to (fL / fC) Imperial ft^2



I'm not quite sure why so many people here use fL instead of nits or cd/m². Metric seems a lot more precise, and the ITU/EBU recommendations for video white are 80cd/m² for monitors, 40cd/m² for projectors. (23.35fL, 11.67fL)

Thanks for that.


I'm still confused, though. What value should I be looking at in CalMAN?
 

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Quote:
Originally Posted by joikd /forum/post/16929919


Thanks for that.


I'm still confused, though. What value should I be looking at in CalMAN?

A capital Y denotes luminance, which is screen brightness' so you want to look at the Y value of a 100% white pattern.

EDIT:




In this imagejust one I had already uploaded for another purpose (sorry, it's using a custom layout I made, and ignore how bad the readings arethey're pre-calibration) look at the grid I have on the lower-left.


You have xyY values for 0-100% grey in 10% steps. So in this case, the projector's brightness is 4054cd/m².
 

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Discussion Starter · #7 ·
Andrew, thanks again for the info.


The only way that I can get Y to over 30 is to set my display's contrast to close to 50 in Bright / High mode. This is a Mits. 73837. If I use Natural / Low, I can only hit the high twenties with Y even with contrast maxed out. Does that sound right? I feel like I'm still missing something.
 

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I'm not that familiar with rear-projection sets, but it looks like that's a 73" DLP? I imagine that one that size probably isn't very bright and it will have dimmed over time.


I'm assuming the low/high you refer to is the bulb brightness. What happens if you use natural/high?


Being a DLP, there shouldn't be any problem maxing out the contrast. (just check there's no clipping)
 

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Quote:
Originally Posted by sotti /forum/post/16936181


OMG what is throwing 4000cd/m of brightness?

My Sony HW10 measured about a foot from the lens. (was actually up to 5800cd/m² when I repositioned the i1Pro)


That translates to about 40cd/m² off my 118" Carada BW screen though.
 

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Quote:
Originally Posted by Federico /forum/post/16957214


"...was actually up to 5800cd/m² "


andrewfee


Do you use your i1Pro facing the projector? Isn't the Measurement range: 0.2 to 300 cd/m2 for the i1Pro? Maybe I'm confused.


Federico

In CalMAN without the diffuser (reading off the screen) it's saying the limit is 3,000cd/m² though I don't know how you would get close to that, and 30,000cd/m² with the diffuser attached. (which I assume cuts out a lot of light and is then corrected in software)


It would be great if someone from SpectraCal could clarify this.
 

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Quote:
Originally Posted by andrewfee /forum/post/16957275


In CalMAN without the diffuser (reading off the screen) it's saying the limit is 3,000cd/m² though I don't know how you would get close to that, and 30,000cd/m² with the diffuser attached. (which I assume cuts out a lot of light and is then corrected in software)


It would be great if someone from SpectraCal could clarify this.

The published spec for the i1Pro is 300 cd/m² but we found it won't give an error until over 3000 cd/m². With the diffuser is about a 10/1 ratio.
 

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That answer one of my question about the difference between softwares using the i1 Pro. With the software I'm using the limit is fixed at about 1000 cd/m2.

I love the fast response from you people at Calman. I think is time for me to try your software. Thanks for the info Derek.


Federico
 
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