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SPL800
Joined: 10 Nov 2009
Posts: 164
Location: Israel
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| Posted: Mon Nov 27, 2017 7:56 am Post subject: changing projecting distance |
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I will need to change my projecting distance
Today my PJ (Barco 1209G) is hanged at a distance of 3.6 meter from the screen.
The picture from this distance is perfect.
I will need to move the PJ from the screen to 5 meter.
Am I going to have a loss in the picture quality due to this?
Thanks
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barclay66
Joined: 27 Jun 2011
Posts: 1304
Location: Germany
TV/Projector: Marquee 9500 Ultra
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| Posted: Mon Nov 27, 2017 8:46 am Post subject: Re: changing projecting distance |
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| SPL800 wrote: | | Am I going to have a loss in the picture quality due to this? |
Hi,
Yes, if You don't find suitable replacement lenses. With the lenses You most likely have (HD-10E/HD-120), the picture at this distance will be too big for Your screen and You won't be able to reduce its size as the CRT lenses don't have any zoom adjustments. Due to this, You will have to reduce horizontal and vertical raster size through the projector's controls (without any guarantee that their range will be sufficient) and will end up with only using a small portion of the CRT phosphor. This will reduce sharpness, brightness and resolution.
As far as I know, lenses for larger throw are HD10GT17, HD10GT26 or HD10GT30. Others may have more experience with this...
Regards,
barclay66
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SPL800
Joined: 10 Nov 2009
Posts: 164
Location: Israel
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| Posted: Mon Nov 27, 2017 9:28 am Post subject: Re: changing projecting distance |
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| barclay66 wrote: | | SPL800 wrote: | | Am I going to have a loss in the picture quality due to this? |
Hi,
. With the lenses You most likely have (HD-10E/HD-120), ,
barclay66 |
Thanks barclay66
i think i might have HQF900
my screen size is also important. forgot to mentioned that is 2.85 meter width.
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cmjohnson
Joined: 03 Apr 2006
Posts: 5180
Location: Buried under G90s
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| Posted: Mon Nov 27, 2017 10:19 pm Post subject: |
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That's a picture width of 112 inches. You're going to be driving the tubes REALLY hard to get a good brightness level, and that means short tube life.
My opinion is that's just too big if you want your tubes to last very long.
I don't recommend a screen wider than 8 feet. But that's just me.
However, since odds are that most enthusiasts are heading for a digital projector in the reasonably near future, go for it. Work
those tubes, get the big picture, and when the tubes show too much wear, time for a digital.
A projector that's retired with pristine tubes was wasted. Use them up!
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SPL800
Joined: 10 Nov 2009
Posts: 164
Location: Israel
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| Posted: Tue Nov 28, 2017 7:32 am Post subject: |
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[quote="cmjohnson"]That's a picture width of 112 inches. You're going to be driving the tubes REALLY hard to get a good brightness level, and that means short tube life.
My opinion is that's just too big if you want your tubes to last very long.
thanks
i'm thinking of keeping the PJ as long as i can.
I will try first to set with the HQF900 lenses.
i live in israel and shipping cost for 3 heavy lenses will be very expansive. therefor I will try first to set with the HQF900 lenses.
if i see that i need to set high levels of brightness / contrast. that means i need to change the lenses?
if so changing the lenses will be easy.
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cmjohnson
Joined: 03 Apr 2006
Posts: 5180
Location: Buried under G90s
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| Posted: Tue Nov 28, 2017 3:38 pm Post subject: |
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As long as the lenses focus on that screen there'd be no reason to change them. HFQ900s are as good as any lenses you can get, and are arguably the best so you probably have no reason to even bother to try other lenses.
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