Read on to follow this real-world example. - Anthony D. Coppedge, CTS, CAVSP

CHURCH

"...The projector needs to be at the back of the sanctuary, which is about 72 ft from the screen.
Our current projector isn't bright enough to see unless all the windows are closed and the lights
are turned off. So we are in the market from a new projector."

Anthony D. Coppedge

OK, first question: Why does it need to be at the back of the sanctuary? Sometimes there isn't a
way to get it closer. Yet many times, it's an assumed place to put the projector - with no other
reasoning.

In order to install a projector a long distance from the screen a long-throw lens will be required.
Just like a camera needs long ‘zoom' lenses to see objects far away, the projector needs a longthrow
lens to ‘shoot' the image that far away without filling up the entire wall.

Here's the first fact: Nearly all long-throw lenses allow less light to leave the projector because of
the increased F-stop of the lens. There are very few exceptions to this, and those that do are
very, very expensive. So that "really bright projector" may lose up to 50% of its brightness with a
poor quality long-throw lens.

Therefore, by using 'less glass' (shorter throw distance lenses), you will have more light (lumen)
at the screen. And an easy way to do this is to physically get that projector closer to the screen.

CHURCH

"...I've gathered the kindergarten fact that the more lumens you have.... the brighter the projector
is."

Anthony

"The more lumens you have, the brighter the projector." Well, almost.

Here's your second fact: In terms of measured lumen (how "bright"), yes, the more lumen, the
more luminous (intensity of light output) the projector. However, brightness is perceived by the
mind.

Our eyes do not respond in a linear fashion to increased light output. For example, if light output
increases by a factor of 10, our eyes do not perceive a ten-fold increase in brightness. In fact the
human eye senses changes in light output on a logarithmic scale, which allows our eyes to be
sensitive over an extremely wide range of light levels. If you double the number of lumen, then
the subjective perception will be that the "whites" get 25% brighter.

A simple demonstration of this is a darkened room with only a candle. You can see, but barely.
Yet your eyes can adjust to a bright summer day outdoors just as easily. If our eyes responded
linearly, we would either be able to see in darkened conditions or in bright conditions.

Let's use an example of two projectors, based on the American National Standards Institute's
(ANSI) facts:

PROJECTOR 1 - with 1000 lumen and a contrast ratio of 400:1 (ANSI);

PROJECTOR 2 - with 1300 lumen and a contrast ratio of 150:1 (ANSI).

PROJECTOR 1 with only 1000 lumen will appear 'brighter' (to your eyes) than PROJECTOR 2
with 1300 lumen. To understand this, read on.

Since a video projector cannot project "black" light, control over the ambient (room) light is critical
to attain an acceptable contrast ratio (white-to-black ratio). In reality, contrast ratio performance
and screen dynamics are just as important as light output when it comes to displaying satisfactory
images. So when looking at the projectors, the ANSI (not On/Off) contrast ratio can be very
important.

Therefore, a projector with a higher ANSI contrast ratio will look brighter than a similarly ‘bright'
projector with less contrast ratio.

CHURCH

"We want to keep the price as low as possible - if possible, under $5000. I was kind of wondering
if 800 or 900 lumens would be ok...because I found a projector for $2000 that had a 900 lumen
rating."

Anthony

And we come to the #2 issue that churches typically bring up: price.

ANSI has come up with mathematical equations to determine the size of screen needed, the
viewing angles required, the brightness requirements and even the defined ratios based on the
type of content. What does all of that mean? That a given room will have unchanging math to
measure exactly what type and size of screen you'll need, the minimum requirements for
projector resolution and brightness as well as other essential information.

In the above quote from the church, we can give the $5,000 dollar figure (or any figure, for that
matter) proper context. I offer the following analogy:

If a church realized a need for a larger sanctuary, do you think they would hire an architect with
the statement, "We've raised $500,000. Say, what kind of sanctuary can we buy for that?"
WHAT?!? Of course they wouldn't!

Factors such as attendance, worship style, denominational structural issues (placement of a
cross, altar, pulpit, etc.), land availability, growth studies, etc. will be carefully considered to give
the architect an idea of the scope of work. With that type of information in hand, the architect
would begin defining how the church would use the room and what limitations were involved.
Only at that time can the architect come back with a budget figure.

So it goes with technology. To assume a random dollar amount (budgeted through random
guesswork or otherwise) for a technology upgrade is EXACTLY the same as the above example
for building a sanctuary on a pre-assumed, non-researched dollar amount.

To summarize this thought: The NEED determines the budget, not the other way around. And, as
an added freebie bonus thought: "If you can't afford it, then ask yourself ‘can you adjust the
need?' If not – wait and budget!" The church was asking the wrong question: it didn't matter if 800
or 900 lumens was "bright enough". Also, the $2,000 budget may have been way too much or not
nearly enough. It would be impossible to answer their question without knowing at least the above
mentioned facts.

CHURCH

"We need the sanctuary fairly bright, and a lot of light spills on the screen. So the projector needs
to be bright...what would you suggest the lumens to be?"

Anthony

We now come to the typical #3 problem most (but not all) churches face: bright rooms.

Allow me to illustrate the importance of light control on the screen. If you've been to the local
movie theatre, and watched the trailers play with the lights still on – before the movie begins –
and then noticed how much brighter the movie looks when the lights are off - you've seen this
effect firsthand. A projected image will always look better when the light is kept off the screen.

Controlling the light on the screen can save significant amounts of cash on a projector.
How is this so? If the screen is protected from lots of direct or indirect (bounce) light, it is possible
to use less bright (read: less expensive) projector.

In determining the type of projector, and its needed brightness (lumen), the size of the screen and
the amount of light on the screen will have to be taken into consideration.

While I'd like to give the church a direct answer (like "3000 lumen"), it would be inaccurate to
guess. There are additional math and light meter readings that are needed to answer this
question, and we do not have those variables. A consultant or qualified design/build firm with the
necessary metering equipment and mathematical equations is required to accurately detail the
exact needs of the church in our examples.

SUMMARY

I applaud this church for asking questions instead of spending foolishly. They are asking with
limited knowledge and need the help of a professional to know what are the right questions to
ask, and, more importantly, what it will take to provide a solution for them.

Over and over again in my work with churches, I find these same types of questions. The
answers are found through educating the churches in their technology purchases. The more
information they have to make informed decisions, the better stewards they will be with God's
money.

I wish this stuff were simpler. The facts speak for themselves: to do it right, you must take all of
the factors into consideration and look at it as you would a new building program. To do less
would be poor stewards of the money God entrusts to you.