Black Level and Gamma of DLP budged projectors - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 7 Old 02-25-2014, 12:39 PM - Thread Starter
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Hello, I'm new to this forum so I apologize if this question was already answered some were here. I have Benq W1080ST projector in a fully black room (wall and ceiling). I calibrated it with Spyder4 and HCFR. Picture quality is very good with one problem, black levels are weak especially in the mostly dark scenes.

I played around with Gamma switching it from 2.2 to 2.4 and up and it does make significant improvement to the black levels but at the cost of shadow details. So here's my question. Why DLP suffers from weak black levels to begin with, and why can't i improve black levels of the projector without changing the Gamma setting? It's clear that projector is capable of deeper blacks when I increase gamma. Thank you in advance.

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post #2 of 7 Old 02-25-2014, 12:52 PM
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No advances in DLP chips have been made in years. Prices have come down, builds gotten cheaper with lower quality.
Black is made by pointing the DLP mirror to a black light absorbing material, the lamp is still pumping out light. The brighter the lamp, the more light there is to escape out the lens. Changing gamma does not change the MLL output of the unit when displaying a video black, such as a fade to black or black bars in a wide screen movie.
You may have something set wrong with your HDMI levels so the do not match your input device, or possible you did not set brightness and contrast properly, or you are just not happy with the capability of a sub $1000 projector...

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post #3 of 7 Old 02-25-2014, 02:44 PM - Thread Starter
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well that's the thing i set brightenss correctly using calibration BluRay disc. e.g. blacker than black does not show and +1% over black is barely visible. But even if i put a pure black field on the screen and then change gamma from 2.2 to 2.4 i see it get darker. if i just reduce brightneess it does not. So my question was why would that be the case? Since gamma adj doesn not change physical properties of DLP and light leakage.

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post #4 of 7 Old 02-25-2014, 03:01 PM
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My guess is you have a level missmatch between your input device and your projector. Are you using a BR player or a Computer / media player for input?

Try downloading the AVS 709 Calibrations disk from the Calibration forum to set the brightness and contrast.
You may also want to search benq in the calibration forum as there were some post from another owner who had level issues.

Doug
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post #5 of 7 Old 02-25-2014, 04:08 PM - Thread Starter
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Thank you, I'll try that. I'm using blu-ray player as input. Also that's the disc I used to set brightness and contrast. Actually followed calibration guide that uses hcfr and that disc.
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post #6 of 7 Old 02-25-2014, 04:24 PM
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There is a trick you can do to set brightness with a DLP.
Display a 0% full field pattern
Stand very close to the screen
Turn brightness up and you will see tiny dancing dots on the screen almost like insects.
Now turn down brightness till the stop moving, it should be very apparent.
You now have brightness set so with video black the micro mirrors are off, that is your lowest level of light output.
If you turn it down lower you will see the mirrors start to move again.. you don't want that.
Now put your brightness pattern up and see if 17 is flashing, it should be, if it is not, bump it up one or 2 clicks till it is just visible flashing

Please note, you need to recheck brightness after contrast is set .. and vice versa.

Good luck!
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post #7 of 7 Old 02-25-2014, 06:17 PM - Thread Starter
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Thank you for this piece of info.I didn't know that about DLP i'll definitely give it a try.

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