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Boilermaker
Joined: 21 May 2006
Posts: 527
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| Posted: Wed Feb 01, 2012 12:39 am Post subject: |
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| Quote: | | I would have a hard time choosing a CRT over the JVCs if I didn't have a five CRTs already |
If you saw a blend, the decision would be easy especially since you already have the CRTs. It would cost you about 1/2 the cost of a new JVC with a good anamorphic lens to just blend what you already have. It really isn't that hard to do. Just takes time.
Bob
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Spanky Ham
Joined: 22 Mar 2006
Posts: 5643
Location: Comedy Central
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| Posted: Wed Feb 01, 2012 1:59 am Post subject: |
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No that is one thing I haven't seen is a blend. Unfortunately, I don't have the house to do a blend at this time.
As for 9" vs 8", I would think the greater MTF and better lenses with a 9" would make a nice difference with a blend. At roughly 1200x1600, a 9" is going to give you a much sharper image than an 8" especially in the corners.
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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| Posted: Wed Feb 01, 2012 3:27 am Post subject: |
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| Spanky Ham wrote: | No that is one thing I haven't seen is a blend. Unfortunately, I don't have the house to do a blend at this time.
As for 9" vs 8", I would think the greater MTF and better lenses with a 9" would make a nice difference with a blend. At roughly 1200x1600, a 9" is going to give you a much sharper image than an 8" especially in the corners. |
You Just gave me an Idea, but most will cringe at the thought. I have 8" Tubes right now. I know form what I see in the blend zone that the AC optics is the downfall of blending. But if I go to 9" LC i would have to move the PJ's if I maximize the raster.
But maximizing the raster reduces edge focus on the Phosphor and in the lens. Also light drop off towards the edge brings
non uniform gamma across the image where it rises towards the edge needing the use of contrast modulation which affects then the central part of the phosphor making it very difficult to keep things even gamma wise. So if I leave my Chassis where they are and swap in the 9 inch tubes I might be able to get away with it and achieve a better blend zone. Im tired form work right now but would the raster be smaller and or image be larger or smaller moving from HD 145 lens to HD 10 and larger tube face? I have plenty of lee way in screen size since I am not utilizing the entire 13 foot screen.
Ok On my way home, get your thinking caps on and figure out what would happen tube face wise and screen wise.
Athanasios
_________________
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Spanky Ham
Joined: 22 Mar 2006
Posts: 5643
Location: Comedy Central
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| Posted: Wed Feb 01, 2012 4:30 am Post subject: |
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I would have to look at the throw distance numbers of the two lenses. If you have the same image size on both the 8" and 9" tubes, then it would come down to the lens throw distance. Of course the image on the 9" tube will cover a smaller percentage of the overall tube area. I know Paul (elaine benes) mentioned in his testing how much sharper the image is reducing the size on the tube. As a matter of course, I think this is why the industrial sim installs did this. You would have to ask tse what the best size/sharpness ratio would be on the tube. In yours and Bob's case and probably all blends, this is a time when you probably wouldn't want to maximize the raster.
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Boilermaker
Joined: 21 May 2006
Posts: 527
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| Posted: Wed Feb 01, 2012 10:56 am Post subject: |
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| Quote: | | As for 9" vs 8", I would think the greater MTF and better lenses with a 9" would make a nice difference with a blend. |
I wasn't aware that there was any functional difference between the two sizes of lenses.
Also, I forgot - What is MTF?
| Quote: | | At roughly 1200x1600, |
While the final resolution each projector would see is 1064X1600, I agree that if you want to go to "line doubling" of 1600 lines, then the 9" clearly would be the choice. That is certainly the ideal configuration and actually superior to what the 4K projectors are doing. I restricted it to 1200 lines (800X1.5) which the 8" handles easily.
| Quote: | | I don't have the house to do a blend at this time. |
Just curious - What is there about your present room that would stop you from blending?
Bob[/quote]
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Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
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| Posted: Wed Feb 01, 2012 12:58 pm Post subject: |
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Don't confuse blending with any other projector layout; all you need room-wise is to set a second projector next to the first and get a 50% wider screen. The throw formula with blending is typically around 0.95 so it is the largest screen size for the smallest footprint.
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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Boilermaker
Joined: 21 May 2006
Posts: 527
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| Posted: Wed Feb 01, 2012 1:25 pm Post subject: |
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We are not smart -just clever.
Just move your 9" around until you get the same width as you are getting on your blend and see what happens.
Bob
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overclkr
Joined: 08 Mar 2006
Posts: 4227
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| Posted: Wed Feb 01, 2012 1:35 pm Post subject: |
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| Nashou66 wrote: | Ok so what would the outcome be if I left the PJ's where they are and replaced the 8" with 9 Inch tubes ? Would the raster be larger or smaller to get the same image size?
Come on guys, your all smart here.
Nashou |
I'm not 100% sure but I will say this. I do not run my rasters to the edge of the tube face for the very reason you stated. The closer to the edge of the tube face, the more you suffer on edge/corner focus, so yes, I definitely think you would benefit. Not to mention the LC is going to be a huge jump over AC (not like you didn't know that already) 
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Boilermaker
Joined: 21 May 2006
Posts: 527
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| Posted: Wed Feb 01, 2012 1:50 pm Post subject: |
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| Quote: | | The closer to the edge of the tube face, the more you suffer on edge/corner focus, so yes, I definitely think you would benefit. |
I agree completely, which is why I built the huge structure that holds the projectors the way I did. I just loosen 4 bolts and I can slide each projector back and forth as far as I want. I actually moved them back about 4" from the original position just for the reason you mentioned. Right now I'm running about 3/8" away from the edges and am pleased with the focus I am getting.
Bob
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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| Posted: Wed Feb 01, 2012 1:53 pm Post subject: |
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| Boilermaker wrote: | We are not smart -just clever.
Just move your 9" around until you get the same width as you are getting on your blend and see what happens.
Bob |
I know I can make it work in the current locations but.... how much smaller would the raster/image need to be
on the tube face. I am thinking if its close to size it is now on the 8 inch i'll move the PJ's . If its a bit larger maybe 1/4-1/2 inch on either side but still far enough away from the edge of the tube then I'll keep the current locations. Also if it makes it
larger on the screen it will stay. I guess I can cart the 9500LC i have lying around into the theater and set it up to see how it looks.
Athanasios
_________________
Don't blame your underwear for your crooked ass~ unknown Greek philosopher
"Republicans believe every day is the Fourth of July, but the Democrats believe every day is April 15." --- President Reagan
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Boilermaker
Joined: 21 May 2006
Posts: 527
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| Posted: Wed Feb 01, 2012 2:12 pm Post subject: |
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| Quote: | | I guess I can cart the 9500LC i have lying around into the theater and set it up to see how it looks |
.
Now you're smokin'. I'll bet you end up tube swapping and now get enough light to handle that humongous screen.
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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| Posted: Wed Feb 01, 2012 2:55 pm Post subject: |
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| Boilermaker wrote: | | Quote: | | I guess I can cart the 9500LC i have lying around into the theater and set it up to see how it looks |
.
Now you're smokin'. I'll bet you end up tube swapping and now get enough light to handle that humongous screen. |
I'm only using 11.5 feet of the 13 footer!! Now i am wondering if I can fill it with the PJ's in the current location width wise.
That is the question. I have them on unistut but having 170lb pj slide easily on that is not easy!! You need two people
one to take some weight off the mount sytem so the other can move the PJ. I was bitchin and swearin every other word
when I first put it up just to move them forward 2 inches. I took me over an hour.
Take a few days Off Bob and get your ass up here!!! You too Cliff!!! I need motivation , actually some feet kickin my ass
to get me moving.
Nashou
_________________
Don't blame your underwear for your crooked ass~ unknown Greek philosopher
"Republicans believe every day is the Fourth of July, but the Democrats believe every day is April 15." --- President Reagan
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Boilermaker
Joined: 21 May 2006
Posts: 527
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| Posted: Wed Feb 01, 2012 3:05 pm Post subject: |
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If I lived closer, I would already be there and you would have a pair of 9" on the ceiling by now.
Actually, If you were to just install a pair of 4" steel tubing on your ceiling like I did, moving them around is easy.
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Spanky Ham
Joined: 22 Mar 2006
Posts: 5643
Location: Comedy Central
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| Posted: Wed Feb 01, 2012 3:07 pm Post subject: |
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Nash,
I can't find the lens info quickly, but like I said it would just depend on the throw distance difference between the lenses if you kept the absolute image size the same on the tube face i.e. 4"x3". Does anyone have a quick lens reference chart?
| Boilermaker wrote: | | Quote: | | As for 9" vs 8", I would think the greater MTF and better lenses with a 9" would make a nice difference with a blend. |
I wasn't aware that there was any functional difference between the two sizes of lenses.
Also, I forgot - What is MTF?
| Quote: | | At roughly 1200x1600, |
While the final resolution each projector would see is 1064X1600, I agree that if you want to go to "line doubling" of 1600 lines, then the 9" clearly would be the choice. That is certainly the ideal configuration and actually superior to what the 4K projectors are doing. I restricted it to 1200 lines (800X1.5) which the 8" handles easily.
| Quote: | | I don't have the house to do a blend at this time. |
Just curious - What is there about your present room that would stop you from blending?
Bob |
[/quote]
I will start with the last question. My living situation changed, as I rent the house I am in. The owner moved down from S.C. and was supposed to buy another house but it fell threw. He is now living here for the time being. Not sure how long this will last, but I am not optimistic. I remember him asking me what I was going to do in the big bedroom and I just smiled and pointed to the 909s. Oh well.
As for 1600 being superior to 4k digital pjs, I am not sure. The JVC just doubles a 1080p image, so it is 1 to 1. Not sure what the Sony is doing, but I think it has multiple configurations.
MTF is modular transfer function. Scott had a thread on it a couple of years ago on AVS. I would think the 9" lenses would have much better sharpness especially in the corners. I remember the whole 8" 1080p debate and the 8" was resolving it in the center fine, but out towards the edges is where it became soft.
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Boilermaker
Joined: 21 May 2006
Posts: 527
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| Posted: Wed Feb 01, 2012 3:29 pm Post subject: |
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| Quote: | | As for 1600 being superior to 4k digital pjs, I am not sure. The JVC just doubles a 1080p image, so it is 1 to 1. Not sure what the Sony is doing, but I think it has multiple configurations. |
I agree: But to make use of a CIH, the JVC (or whatever) has to scale the video's 800 lines to 2160 which will create issues and then use an anamorphic lens which also has transfer function issues. With the blend, everything is linear. Did I miss something on this?
| Quote: | | I remember him asking me what I was going to do in the big bedroom and I just smiled and pointed to the 909s. |
Damn! I didn't know you had a pair of 909's. If you figure out a way to get them blended, you will become my new hero.
Bob
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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| Posted: Wed Feb 01, 2012 4:04 pm Post subject: |
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Ok MTF, from the famous TSE post on AVS back in 2006;
http://archive2.avsforum.com/avs-vb/showthread.php?t=633597
MTF. Modulation transfer function.
It's a way to put a number on resolution. It looks good. I can barely see it. It is real sharp. Any of these statements can mean different things to different people.
Imagine a light meter that only looks a small slit a few thousands of an inch tall (or a tenth of a mm). If you put up an alternating line on line off pattern at 320 x 240 resolution you would see a bunch of horizontal lines. Now take your light meter and measure the light between the lines and the light at the peaks of the lines. You would measure something like what is shown in 100%.bmp drawing attachment. Because the light between displayed lines would be "0" (or something near zero) your MTF reading would be 100%.
Now increase your resolution to 1600 x 1200. The lines are much closer together now. In fact they are overlapping to the point where there is no longer "black" in between the lines. If the "black" you measure is now one half what you measure at the peaks your MTF is 33%. If you now go to 1536 lines you can imagine the "black" is even a higher light level and your MTF might only be 15%.
10-15% MTF is obvious. When you get down to 3-5% MTF it is getting hard to see with your eye.
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_________________
Don't blame your underwear for your crooked ass~ unknown Greek philosopher
"Republicans believe every day is the Fourth of July, but the Democrats believe every day is April 15." --- President Reagan
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Wed Feb 01, 2012 4:05 pm Post subject: |
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Hey, if I throw you a lead for someone wanting a CRT setup in Greece, you can go pick it up...
Frankly after tweaking one of my late model Oct 2002 9500 Ultras yesterday with all new tubes, I'm pissed that I didn't keep two for myself for a stack!
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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| Posted: Wed Feb 01, 2012 4:07 pm Post subject: |
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| Curt Palme wrote: | Hey, if I throw you a lead for someone wanting a CRT setup in Greece, you can go pick it up...
Frankly after tweaking one of my late model Oct 2002 9500 Ultras yesterday with all new tubes, I'm pissed that I didn't keep two for myself for a stack! |
If I go this spring I might!! What PJ will they be using?
You can still get another Marquee I am sure Curt!!!
Athanasios
_________________
Don't blame your underwear for your crooked ass~ unknown Greek philosopher
"Republicans believe every day is the Fourth of July, but the Democrats believe every day is April 15." --- President Reagan
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