Thinking of a Runco Q-750i - Looking for advice - Page 3

irjs >>> Since you appear to be so interested in Runco and LEDs may i suggest you google "Runco out-the-box brightness for life" and check out the pdf ?
It's a brief description of the Helmhultz-kohlrausch Effect in which perceived brightness appear to increase due to saturation, that brightness increases due to not only luminance but also chromaticity, that more saturated colors are perceived as brighter than pastel versions at the same measured brightness levels.
According to this Runco brochure, that is the reason why LEDs colors appears brighter than colors from UHP/xenon bulbs and in fact Runco claims a 60% increase in perceived luminosity !

Looking back at the first post I would make sure to view the M150 in person and see if the 3D is up to your standards. For active 3D it is right on the edge IMO of being bright enough. Most people seem to display 3D content in overlap mode, which is brighter but not as color accurate. For the price of the M150 you could easily get a used D-73D which is passive and does have the real light output.

Let us know what you decide.

Cheers.

Hey guys,
Tim here. I want to revive irjs's thread because I also have an opportunity to purchase a "demo" Q750i". I wanted to ask you guys a few questions.
First-I have a darkened theater room with a Stewart Studiotek 123"D screen and throw distance is 18 feet. Will this configuration work?
I have read that my screen (123"D) is too large for the Q750i. I spoke to Runco about my HT specs and was told the Runco Q750 lens are specked for each room. Is this true?
Are the 750"s "lens specific" so to speak? I want to upgrade to a better projector and have always been a Runco fan. I am also looking at the jvc 4805 and the sony hw50 as these are in my price range.
I tend to keep the pj's longer than most (currently using an infocus 7200- dont laugh).
3D is not a priority and am looking for the best 2D picture. (I'm still gonna spend a lot of money for a 3-4 year old projector and want re-assurance ).
Also, this Q750 was used in a store for a couple years so does the brightness level decrease over time? (It will come with the warranty). Are the hours of use for the Q750 a factor or should they be?
Any suggestions would be greatly appreciated
Thanks for your help.

Considering the Q750i is an LED based DLP machine you shouldn't have to worry about light level loss or how many hours are on the unit. The LEDs should last well over 20000 hours with a very small amount of loss in lumen output. The Q750i has two lens choices. One is the stock medium/long throw and the other is an optional short throw lens only needed if the distance between the projector and screen is particularly short.

As far as the screen goes, most people would say that 110" is probably as big as you should go with this projector. I don't know which screen material you have but if it's a higher gain screen it may work out just fine.

123" diagonal is 60.2 x 107w or 44.7 ft2

It should produce about 450 lumens

Assuming you have a ST130 (guessing) it has a gain of 1.3.

Screen brightness will be: 450 / 44.7 * 1.3 = 13ftL

Typical target is 16ftL, but 2 things to consider... The 13ftL will be stable, won't lower like a bulb based that might have gone lower. You will be hard pressed to tell teh difference between 13 and 16 ftL if you were exposed to them independently. The LED's are reported to look brighter than the measured lumens. So, it's close and to some extent comes down to personal preference. I personally like much brighter images. I know people perfectly happy with less, particularly in darkened rooms.

On a 110" (D) screen, same calcs come out to 16.25 ftL.

HTH,
Scott

Did you guys buy the extended warranty (5 years for $500)?
Waste of money or wise investment?

I have it, but it was all part of the sale for me. I guess there really isn't a lot that can happen but not knowing how much a demo was used unless there is something is the service menu to tell you I'd go for it.

Jeremy

I have mine on a 1.1 gain 16:9 at 120" I get a measured 12.3 FL at 100" I get 16FL. You should be fine. Even at 12.3 it was brighter than my Vidikron Vision 75 (Runco RS100 Ultra) which measured out at 14 Fls.

I would not get the warranty, but that is just me.

I forget where I read it, but it seems that the LEDs are actually perceived as brighter at the same foot lambert level compared to a lamp based light source. I'll try to find the source. It has something to do with how our brain/eyes perceives the different light source.

There's a white paper on it on Runco's website.

http://www.runco.com/downloads/Other/Runco%20Out%20of%20the%20Box%20Brightness.pdf

Perfect! Thanks, I was looking for that pdf. Yeah, basically because the LEDs produce more saturated colors (while still maintaining accuracy) our eyes see the colors as brighter.

I was reading a review on the Q750i and came upon this quote: ..."because of their findings as to the Q-750i's true performance, Runco doesn't recommend using the Q-750i with a screen larger than 108 inches diagonal"....
Could someone explain this quote to me? Is it because the lumens ( and hence brightness) will decrease with a larger screen?

I have it on a 110" hp 2.8 and it is brighter then the 572 lumens my previous projector had. Both are mounted with the lens even with the top of the material with 18' throw and seats 12.5 back so I'm not taking advantage of all the gain.

If you have a screen up already I would see about an in home demo depending on how good you are with your dealer.

Jeremy

When when get this one calibrated I'll post the lumens as well.
Edited by agrsiv95 - 1/18/13 at 5:49am

I'm not familiar with that directive from Runco. Per my calcs shown previously, and with the defacto Stewart Studiotec 130 reference screen, a 110" will yield a 16ftL image, which is generally considered, just right.

Lumens don't change except for projectors with variable aperture (VA) lenses that stop down the light path. I believe the Q750's optics are Minolta constant aperture (CA) like what's in my 3 chip, but I have not verified this myself. For PJ's with VA lenses, they are brightest at their shortest (widest) throw.

Screen brightness is measured in
illuminance - this is the measure of light coming from the projector, using a illuminance meter. Measured in foot candles fc (or lux)

luminance - this is the measure of light coming off of the screen if you will, using a luminance meter. Measured in foot Lamberts ftL

The (il)luminance changes as you spread a given amount of lumens over a larger area. So as the screen gets bigger, for a given projector output, in lumens, the image will get dimmer (lower luminance)

HTH,
Scott
Edited by GetGray - 1/18/13 at 6:37am

timatraw >>> I purchased a store demo Runco Q-750D and over the past 15 months i have used it for over 4.000 hours without any problems or any noticeable change in onscreen luminance level, which is a lot to say concerning long term reliability of projectors in light of all those posts right here at AVS of so many owners complaining of light engine failure within 400~800 hours, the "pink stripe" LCOS curse, the "green-yellow" Sony SXRD optical block failure, owners demanding class action suites against manufacturers, damage from light bulb explosions, etc, etc.
From my experience, just by using LEDs instead of UHP/zenon bulbs you would be saving yourself a whole bunch of concerns and incoming headaches and the price to pay for that is to carefully match the size and gain of your screen of choice to the more limited luminance output of those Luminus Devices Phlatlight LEDs.
Home Theater Magazine measured a clone of the Runco Q-750i (Digital Projection M-Vision Cine LED) at 17.2 ft-L and minimum black level of 0.002 ft-L on a Stewart Studiotek 100 unit gain screen 100" wide (112" diagonal), which is excellent light output as recommended by SMPTE and keep in mind that contrary to what so many people think, the complete LED R/G/B chipset from Luminus Devices used in these projectors, Phlatlight PT120, can be purchased for less than $250 and from pictures posted online very easily replaceable as they are screwed on a metal board.
Considering your projector comes with warranty the other questions i would have asked the dealer would be how much of a discount from msrp, the physical condition of the unit and, out of curiosity, estimated hours of use.

Hey MCaugusto,
What type of screen are you using with your Q-750D?

Well, i am embarrassed to say it and i am sure you guys are gonna "roll your eyes" (and i agree !) but the screen i am still using with my Q-750D is a 76" diagonal curved silver screen (gain of 10:1) leftover from the late '80's manufactured by Electrohome which i've owned since my last CRT projector.
I have checked again and again for reviews and opinions concerning screen choices and got samples from some manufacturers that made me decide between the Da -Lite High Power 2.4 and the Mocom Technologies Mega Brilliance silver material - i am sucker for high gain silver screens - but when i read some reviews posted here at AVS concerning imperfections in the fabric of the High Power 2.4 as well as the pricing for the Mocom Technologies, i have literally been "frozen" with indecisiveness.
In this day and age when one can walk into Walmart and buy a Vizio 60" LCD/LED HDTV on sale for $699 it is hard to justify spending the same amount of money on a screen and besides i now find myself considering the eventual purchase of a 80"~90" flat panel LCD (preferably UHDTV 3840x2160) within the next year or so and spending over $1.000 for a screen that i might have to sell within one to two years gives me pause.
Meanwhile, since these top-of-the-line projectors using the DarkChip4 0.95" diagonal DMD chip from TI offer the sharpest projection image available, i move my chair to within 5 feet from the screen, make sure that my Darblet is on, and just enjoy those amazing LED colors and best-in-class ANSI contrast ratio.
Edited by MCaugusto - 1/21/13 at 7:49am

Scott,
Thanks for the education on luminance, lumens and foot lamberts.
It took me time to figure out what you were explaining in post #65.
I think Im starting to understand the terminology better.
I didn't realize how little I knew about these important factors.

No Problem. That is the fundamentals on knowing how to properly size a screen for a projector. Given a known output in lumens (not usually what the mfgr specs). Runco is an exception to that, their outputs are usually very close to what I measure.

Thanks for all your input.
I'm getting ready to pull the trigger.
Is anybody using a Q750 with a large (> 120") screen?

[quote name="timatraw"
Is anybody using a Q750 with a large (> 120") screen?[/quote]

---

AVS member rovingtravler has answered that exact question in post # 68 of this thread and member GetGray in post # 65 has posted some calculations that confirm rovingtravler's measurements almost to a tee...

Tim,
Did you end up getting a Q?

Hi Guys

Just wanted to revive the thread and post a reply - I finally mounted my Runco Q750i using a VCM mount yesterday. Needless to say, yes the unit is built like a tank and I spent almost the entire day fastening making sure the mount was strong enough to hold this beast. My test to ensure it could hold the projector? Hang off the mount, yes all 165 lbs of me. After I finally had it mounted, I had trouble calibrating the vertical alignment of the image. I'm sure all my measurements are correct, and I'm about 16 feet away from the top center of the screen. The manual suggests to adjust the vertical lens through the menu (which I did) but I didn't get it far enough down the screen. My projector is still projecting to the ceiling (half way). So apparently there is a manual lens shift (vertical) that can be accessed by removing the bezel and using a hex screw to adjust the vertical lens alignment. It is me or is it should this be easy to do? I'm using the hex counter-clockwise and the lens doesn't seem to be moving. In fact, the screw doesn't seem to be moving. Do I need to use force on top of the lens or inside the cavity to get this thing down or is it time to call Runco/dealer for help/assistance?

If any Runco dealers or owners can reply and offer some tips, it would be much appreciated.

Yeah the panel is a pain to access. Go back into the menu and disable all of the electronic image shifting you did. You'll get better results, picture quality wise, by using real vertical lens shift. If the lens is in line with the top of your screen (that's the way i read that) you should be able to get the image to fit the screen. Try using the Allen wrench in the other direction. If it doesn't move that way either you've got a problem. I had the cogs break on the horizontal lens shift on my planar pd8150. They were made of plastic. The Q750i has the same internal chassis as the planar. I don't understand why they didn't add actual knobs for you to twist for lens shift. I guess its for aesthetic reasons? Don't over tighten in either direction or you can break the cogs and it won't move at all. From the picture it looks like you have the lens all the way shifted vertically.
Edited by Seegs108 - 3/3/13 at 12:26pm

The screw in front holds the cover in place, remove it and slide the bezel to the left to gain access to the two adjustments. There is one on each side of the lens.

Hi Guys

I got it working, The screw that held the vertical shift in place (the plastic piece) was completely dislodged. I removed the screw from the chassis and put it back in and it worked. The vertical shift lens now works like a charm. You're right, the results are much better with the vertical/horizontal lens shift. Also, on one of the HDMI inputs, I'm getting snow on the picture. Is there a setting that I need to turn off or is it likely my HDMI cable?

I purchased a demo unit which also seems to have ISF settings calibrated. I understand it can be quite costly to get these calibrated yourself so I don't want to reset to factory settings. How do I find out if it has in fact been calibrated via ISF?

One other question, in the settings menu it shows firmware. Is there a new firmware or better firmware to improve the picture quality? I'll have to go back and check what it is but I know there was a version number next to the LED firmware/driver.

Thanks

An easy test for the HDMI cable is to just switch ports to see if you get the same results. If you switch and things seem fine you know its the port and not the cable.

As far as the ISF and firmware goes, its best to call the dealer you bought it from and ask about both. They should have an answer for you.
Edited by Seegs108 - 3/8/13 at 11:52am

Hey guys. Late reply but still may be relevant for some. I'm using my Q-750i on a 130" 2.35:1 Stewart Firehawk and brightness is fine. Definitely brighter than my JVC RS20 after a couple of hundred hrs on a lamp and just slightly behind my old LS-5. The size of my screen probably pushes it a bit but I'm getting away with it and the picture still looks awesome on good content.