Film-Tech Forum ARCHIVE: Best Meter for Measuring Screen Brightness?

This is topic Best Meter for Measuring Screen Brightness? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Chris Rasmussen (Member # 3015) on 09-11-2009, 07:43 PM:

Greetings!

A tech who's borrowing my Pentax Spotmeter V says it's insufficient for reading screen brightness due to shutter strobing.

Can someone suggest a better meter or a way of interpreting his readings (he already has the conversion to foot-lamberts).

Thanks!

Posted by Karl Borowski (Member # 5424) on 09-11-2009, 07:44 PM:

You can use lightmeters for reading ft.-L's? I always thought this had to be done with specialized equipment. . .

If you do have formulae available for converting meter readings to ft.-L's, I'd appreciate if you could post some here!

Posted by Steve Guttag (Member # 268) on 09-11-2009, 07:59 PM:

The problem is in the averaging...for working with film projectors, the spot meter must average the light over cycle of the shutter.

Most photographic meters measure incident light. For Cinema, one is interested in what bounces back off the screen (reflected light).

As for meters...the USL PSA is by far the most useful of them. It is like having 45 light meters in one unit...not only will you know what the light level is but also its distribution. They even have the ability to judge flicker and image jump. And when you are done, give you a print out as a reference.

One of the problems I find with most measuring equipment is the people operating it...they often don't follow procedures or realize what they are doing and thus get erroneous readings.

Steve