CurtPalme.com Home Theater Forum

[that1crzywhtguy]

Hi there! I'm setting up my beloved Runco again in my new place, and the throw distance is really kinda cramping my style. According to Barco (this is a rebadged Cine 7), the lens calculation is this: PD[inch] = 1.2642 x SW[inch] + 8.48. So, 127" for a 94" wide screen. This means in order to stay behind the projector on it's table, the couch has to be much further back than is ideal. If it would help, I can update the thread with some pictures of the setup (I'm at work atm).

So, are other CRT lenses compatible, maybe some with a shorter throw distance? Any advice would be GREATLY appreciated!

Cheers
Sterling

[kal]

Don't go by throw distance calculators. Many are way too conservative and don't use enough tube face. See the instructions I have here for the correct way to figure out throw for any projector:

http://www.curtpalme.com/TubeCondition_PoorInstall.shtm

Kal

[kal]

Don't go by throw distance calculators. Many are way too conservative and don't use enough tube face. See the instructions I have here for the correct way to figure out throw for any projector:

http://www.curtpalme.com/TubeCondition_PoorInstall.shtm

Kal

[that1crzywhtguy]

Thanks so much for the recommendation!

I actually have used that very guide many times. When I get my unit it had less than optimal tube wear. I used a guide here to fix it (https://www.curtpalme.com/forum_archived/viewtopic.php@t=23374.html

So I took a measurement, and with my current lenses, it's 129" to the screen.

If I could just get it closer....

[kal]

That's one of the issues with CRT projectors: 3 giant lenses that are fixed focal length. There's no zoom. That said, you wouldn't want one on 3 lenses. Not only would that hurt the image quality (a fixed focal length lens is easier to build better than a zoom) but at that size and times 3, it would cost a stupid amount of money (and CRT projectors were crazy expensive when new to begin with).

Everything about CRT placement was ensuring proper throw and working the room around that. Some will go as far as knocking a hole in a wall if they have to, using a high quality mirror, etc. There's only one place that projector wants to be if you want the best tube usage/light output. No idea what lenses the Barco Cine 7 shipped with but generally speaking alternate lens options where not available for CRT projectors.

Kal

[kal]

That's one of the issues with CRT projectors: 3 giant lenses that are fixed focal length. There's no zoom. That said, you wouldn't want one on 3 lenses. Not only would that hurt the image quality (a fixed focal length lens is easier to build better than a zoom) but at that size and times 3, it would cost a stupid amount of money (and CRT projectors were crazy expensive when new to begin with).

Everything about CRT placement was ensuring proper throw and working the room around that. Some will go as far as knocking a hole in a wall if they have to, using a high quality mirror, etc. There's only one place that projector wants to be if you want the best tube usage/light output. No idea what lenses the Barco Cine 7 shipped with but generally speaking alternate lens options where not available for CRT projectors.

Kal

[virusc]

I have a Runco/Barco cine7 as well. I think they are HD145 lenses but you could retrofit any 7"crt lens in its place but I would not do it. Also, any lens that has shorter throw in general is lesser quality. I would do what Kal said first. The TAC3 lenses that are the shortest throw are all plastic and terrible edge focus and all the good short throw lenses for RP are too short for this application. The factory throw uses a much smaller raster on the CRT but you have to stay within the wear area if you have any, this will be your major problem I would think.

[that1crzywhtguy]

Thanks for the additional info. I was curious if there was a shorter throw option available without a quality loss, and I knew I'd figure that out here pretty quickly!

Like I said above, the raster is maximized already and my wear has been evened out and I can use the whole tube face.

I will likely mount it on the ceiling this summer. For now I'll be happy with it as is!

Cheers

[kal]

I'm going to make up some numbers but the higher quality (all glass) CRT lenses back in the day used to cost a few thousand each. It was a major part of the price behind the units. These days high end digitals with all-glass often cost thousands more and they're MUCH smaller lenses. Again back in the day, the CRT positioning was integral to room design. You worked that in. It was cheaper to move a couple of walls than to possibly spend $10K on different lenses (even if they were available).

Kal

[kal]

I'm going to make up some numbers but the higher quality (all glass) CRT lenses back in the day used to cost a few thousand each. It was a major part of the price behind the units. These days high end digitals with all-glass often cost thousands more and they're MUCH smaller lenses. Again back in the day, the CRT positioning was integral to room design. You worked that in. It was cheaper to move a couple of walls than to possibly spend $10K on different lenses (even if they were available).

Kal

[that1crzywhtguy]

That's interesting and makes a ton of sense! Thanks as always for the perspective.

[virusc]

HD-10 lenses were for the most part $2k - 3k each from 3m. Very special versions were more. I had a price list from the late 1990's at one time during the peak. I don't remember the smaller lenses but they were not cheap either, not even HD-6 lenses so I would say KAL is right. Its been a long time but so I might be off on the exact numbers but the HD10-L's were near the 2k mark. Their was a option for OEM's to order the project chassis without lenses and I remember it was 6-8k less so that is what we did and often used, used lenses.