Home Theater Forum and Systems banner

61 - 80 of 96 Posts

·
HTS Senior Moderator
Joined
·
8,367 Posts
Discussion Starter #61
Well you've made a good start Jack, with a 2.4:1 screen..:T

More and more people are going this route now for their standard 16:9 projection..
It does make life a bit easier with just side masking for 16:9, or not bothering with it at all..
I've never found the need to mask my 2.4:1 screen..

However, you are missing out on full image quality, when you zoom to fill the screen..The pixels are being stretched horizontally and vertically, which degrades the image to some degree..

To give you an idea of how much better it would look, when you use an anamorphic lens..
Next time you have a 2.35:1 movie up on the screen, take a close look at how sharp and detailed it is, prior to zooming..
This is almost the same detail you will see, when a lens is used to expand the image..

If you go the DIY way or buy a lens kit assembly, it's not all that expensive to have a very reasonable anamorphic lens..
 

·
Premium Member
Joined
·
370 Posts
Hey Prof, there's no doubt the anamorphic lens is the way to go
currently, I have a 720 projector, and I sit just beyond the point where I would see screen door when the image is 10 feet wide (thats how wide my screen is)

I've sat on the lens sidelines watching people with more disposable income than myself enjoy some really spectacular setups.

What are the DIY lenses costing these days?
 

·
HTS Senior Moderator
Joined
·
8,367 Posts
Discussion Starter #63
Hey Prof, there's no doubt the anamorphic lens is the way to go
currently, I have a 720 projector, and I sit just beyond the point where I would see screen door when the image is 10 feet wide (thats how wide my screen is)
That's very nice wide screen and it would look absolutely brilliant with Anamorphic projection..

What are the DIY lenses costing these days?
OK..There are two ways of going DIY..

1. Buying prisms from someone like this http://www.crystalfactory.com/CWD46-CWD57-CWD68.asp
The 5"x7" is the size you need, and if you have just rudimentary carpentry skills, it's very easy to make a case for them..
Mark and myself can give you all the info. you need to do this..

2. You can buy a lens kit from HT Brothers or CAVX..I have the CAVX lens..http://cavx.blogspot.com/2007/04/4-prism-lens.html
Just scroll down for pricing..

As you can see, a considerable saving on buying commercial lenses..
 

·
Premium Member
Joined
·
33 Posts
This is a really useful thread, thanks :)

I don't even have a projector but when I do I would like to do it 'properly' and go for a CIH setup. This thread has helped me understand what actually happens and the benefits.

Can someone tell me the downsides to this approach?

Assuming I have a 2.35:1 screen, do I need to remove the lens when using some sources or can you just put up with black bars at the sides? I expect most of my movies will be HD and at least 2.35:1 but some DVDs will be 16:9, the only 4:3 I have will be something like Star Trek on HD-DVD.

What I would prefer is a setup I don't have to keep fiddling with each time I want to play a disc; I use an HTPC as a source so have to jump through enough hoops already :foottap:

Thanks,

Adam
 

·
HTS Senior Moderator
Joined
·
8,367 Posts
Discussion Starter #65
Assuming I have a 2.35:1 screen, do I need to remove the lens when using some sources or can you just put up with black bars at the sides? I expect most of my movies will be HD and at least 2.35:1 but some DVDs will be 16:9, the only 4:3 I have will be something like Star Trek on HD-DVD.
Adam,

I leave my lens place for 1.78 :1,1.85:1 and 2.35:1 aspect ratios..
I don't bother about any black bars at the sides.. and with my current screen the blacks are so good that it almost looks like it's masked anyway..
Some people do however prefer to mask the sides when showing 1.78:1 movies..

The other thing that helps to minimize adjusting procedures is that some 1.78:1 movis can be shown in 2.35:1 AR..I do this with a number of my movies..
 

·
HTS Senior Moderator
Joined
·
8,367 Posts
Discussion Starter #67
Hi takumi and welcome..

The best projector for Anamorphic projection will depend on several things..
Firstly, we need to know whether you prefer DLP or LCD..
What your projection distance and throw ratio will be..and whether you need a projector with vertical stretch, or whether you have a scaler or DVD player that will do the vertical stretch..
I presume your looking at getting a 1080p projector for that budget..
 

·
Registered
Joined
·
100 Posts
thanks, now i will search for the difference between dlp and lcd projector. the only info i can give u is that i have 16'x23' media room with french doors in the back, its also pre wired for 5 speakers.
 

·
HTS Senior Moderator
Joined
·
8,367 Posts
Discussion Starter #71
scaler? vertical stretch? i have a lot to learn.
OK..so it looks like you're starting from scratch..
This makes it a simple choice if you follow what a lot of people have done, who have an anamorphic system..

DLP projectors have a number of makes that provide vertical stretch..and is generally the preferred type of projection system..

Vertical stretch is where the projected image is electronically stretched vertically by the projector, which makes people look tall and skinny..and then the lens expands the image horizontally to restore the correct geometry..
Without going into all the other aspects of this..I suggest that you have a good read of my "16:9 vs 2.37:1 CIH Screen" in this forum..as well as the postings by Mark Techer..
You will find all you need to know about Anamorphic projection..

As far as the makes of projector to look at..These would be my choices..

Benq
Optoma
Sony
Panasonic

All have the vertical stretch facillity..but some of the earlier models may not..

I see your theatre room is 23' long..so I would get a projector that has a fairly long throw lens, to help reduce pincushion effect..
 

·
Registered
Joined
·
613 Posts
A long throw can be determined by two methods -
1. The Throw Ratio where the native 16:9 image width is divided into the distance from the screen to the projector.
2. How many image heights the projector can be back from the screen.

If we take my BenQ W5000, at the min zoom (smallest image) the TR (from 1) is about 2.2) or 3.1 times the image height. Therefore I would really consider the BenQ W5000 to me a mid range throw device, not a long throw device which would be closer to 3.7x the image height...

Mark
 

·
HTS Senior Moderator
Joined
·
8,367 Posts
Discussion Starter #74
If we take my BenQ W5000, at the min zoom (smallest image) the TR (from 1) is about 2.2) or 3.1 times the image height. Therefore I would really consider the BenQ W5000 to me a mid range throw device, not a long throw device which would be closer to 3.7x the image height...

Mark
Mark...At a 2.2 TR..do you notice much difference in pinchusion effect over your previous Sony projector..which had a much lower TR I believe.?

I always thought that the earlier BenQ projectors had a fairly short throw lens, but I'm at 3.5 times the image height, with a 1.8 TR.!!
 

·
Registered
Joined
·
613 Posts
Mark...At a 2.2 TR..do you notice much difference in pinchusion effect over your previous Sony projector..which had a much lower TR I believe.?

I always thought that the earlier BenQ projectors had a fairly short throw lens, but I'm at 3.5 times the image height, with a 1.8 TR.!!
Prof,

Maybe I have got the math wrong...and it looks like your right...

My screen is 949mm high x 2.37 = 2250mm.

1st row 2000mm.

2nd 3000mm (a bit tight).

Projector, just behind that at about 3200mm.

Therefore TR should be 3200mm / (949 x 1.78) = 1.89:1

Sorry for the confusion about the 2.2TR...

So anyway, the pincusion was less than the 1.3:1, but not totally reduced. My screen is adjustable, so I can compensate here.

I am however looking to extend the Throw Ratio, so will most likely go to a VC lens next.

The TR won't change as TRs for VCs are taken off the Scope Image width, not the 16:9 image width, but the projection distance will increase 3200mm to over 4250mm allowing better spaced seating.

Also with a VC, you don't get pincushion at all and I can actually go back to a flat screen. What you get is "barrelling" but the barrelling is much less than the pincushion.

CA that normally runs vertcially with a HE will now run horizontally, but I am not expecting to see any CA with my new lens (a shamless plug :D) that is under development right now and will use achromatic doublets.

Lastly is the focus issue where typically a DIY prism lens tends to loose a bit of shapness towards the edges, the VC maintains sharpness all the way and this is why Panamorph used the VC design for so many years. If there is to be any loss in sharpness with the VC, it will be seen at the top and bottom of the image not the sides.

My lens is also cylindrical, not prismatic, so I have designed anstigmatism correction into the design as well...

The only problem with using a VC is that the lens must remain in the light path all the time or the 16:9 image become much taller. This is not really a problem (with 1080 anyway) as the light levels, pixel density and colour all remain the same when leaving the lens in place - which I have been doing anyway with my HE lens. Removing the lens may even reqire two (or more) calibration settings...

Mark
 

·
HTS Senior Moderator
Joined
·
8,367 Posts
Discussion Starter #76
Prof,

Maybe I have got the math wrong...and it looks like your right...

My screen is 949mm high x 2.37 = 2250mm.

1st row 2000mm.

2nd 3000mm (a bit tight).

Projector, just behind that at about 3200mm.

Therefore TR should be 3200mm / (949 x 1.78) = 1.89:1
It looks like your screen size and TR are almost identical to mine.:bigsmile:..except I don't sit quite as close as you do..don't have the same resolution as the W5000..


So anyway, the pincusion was less than the 1.3:1, but not totally reduced. My screen is adjustable, so I can compensate here.
I'm guessing that with your current set up now, you probably have about the same amount of pincushion that I'm getting..
It would seem that the W5000 would fit nicely in my room..

The TR won't change as TRs for VCs are taken off the Scope Image width, not the 16:9 image width, but the projection distance will increase 3200mm to over 4250mm allowing better spaced seating.
WOW!!.I had no idea that VC would increase the projection distance by that much!!..which would put my projector outside in the yardl!!:bigsmile:

Also with a VC, you don't get pincushion at all and I can actually go back to a flat screen. What you get is "barrelling" but the barrelling is much less than the pincushion.
That would be nice to have but unfortunately I don't have the length in the room..

CA that normally runs vertcially with a HE will now run horizontally, but I am not expecting to see any CA with my new lens (a shamless plug :D) that is under development right now and will use achromatic doublets.
I'm very interested to see the pics of that lens when it's finished..

Lastly is the focus issue where typically a DIY prism lens tends to loose a bit of shapness towards the edges, the VC maintains sharpness all the way and this is why Panamorph used the VC design for so many years.
That would be nice to have..


If there is to be any loss in sharpness with the VC, it will be seen at the top and bottom of the image not the sides.
I would find that annoying, because I'm more aware of the sharpness, top and bottom of an image when watching a movie, rather than the sides..and it's only when I specifically look at th sides that I notice it in some scenes..

My lens is also cylindrical, not prismatic, so I have designed anstigmatism correction into the design as well...
Cool!!

The only problem with using a VC is that the lens must remain in the light path all the time or the 16:9 image become much taller. This is not really a problem (with 1080 anyway) as the light levels, pixel density and colour all remain the same when leaving the lens in place - which I have been doing anyway with my HE lens.
Likewise for me...I'm even leaving the lens in place for all AR's of the movies I buy or rent, so everything is viewed in cinemascope...even if the occassional head gets chopped off!!
 

·
Registered
Joined
·
613 Posts
It looks like your screen size and TR are almost identical to mine.:bigsmile:..except I don't sit quite as close as you do..don't have the same resolution as the W5000..
1080 rez allows you to sit close as you simply do not see the pixel structure. 2x the image height is actually quite good, but until I saw this for myself, I didn't believe it...



I'm guessing that with your current set up now, you probably have about the same amount of pincushion that I'm getting..
It would seem that the W5000 would fit nicely in my room..
Probably would...I like the BenQ despite the neg reviews it got from around the world....

WOW!!.I had no idea that VC would increase the projection distance by that much!!..which would put my projector outside in the yardl!!:bigsmile:
I want the projector behind the seating and not above it, so this is the only way to do that...
That would be nice to have but unfortunately I don't have the length in the room..
Can't have everything :D


I'm very interested to see the pics of that lens when it's finished..
There will be plenty of pictures, don't worry about that :D

I would find that annoying, because I'm more aware of the sharpness, top and bottom of an image when watching a movie, rather than the sides..and it's only when I specifically look at th sides that I notice it in some scenes..
And the reason I am going cylindrical this time too - you can adjust the focus of the lens to be razor sharp corner to corner - prisms will never allow that..


Likewise for me...I'm even leaving the lens in place for all AR's of the movies I buy or rent, so everything is viewed in cinemascope...even if the occassional head gets chopped off!!
I won't chop heads. I use eithe the 4x3 mode or the letter boxed mode to ensure that I have true CIH for those ARs...

Mark
 

·
HTS Senior Moderator
Joined
·
8,367 Posts
Discussion Starter #78
Probably would...I like the BenQ despite the neg reviews it got from around the world....
I've only ever seen good reviews..What are the negative aspects?

And the reason I am going cylindrical this time too - you can adjust the focus of the lens to be razor sharp corner to corner - prisms will never allow that..
So, still no possibilities for marketing the new lens.?

I won't chop heads. I use eithe the 4x3 mode or the letter boxed mode to ensure that I have true CIH for those ARs..
.
I'm afraid I've been utterly spoilt with cinemascope images..to the point where I'm very reluctant to watch any movies in 1.78...It just seems so boxy!!..almost like the old 4:3 box TV..:R
 

·
Registered
Joined
·
613 Posts
I've only ever seen good reviews..What are the negative aspects?
Where to begin? I don't want to come across as negaitve, but there are many issues with these projectors. BenQ have done the right thing and arranged repair or exchange when faults are reported so well done to them for that. The 8720 was a beast of a projector, and I had just hoped that quality would have been carried into the new models. It seems that was not the case and that legacy ended at W10000.

Some of the issues are simply manufacturing - the have done the right thing by keeping prices low, but QA did drop a touch - it had too. Take the lenses for example. Many (not all, as mine seems to be one of the good ones) have silicon contamination. I am told that this means that the sand used to make the glass was not pure silcon sand, and I have even seen artifacts such as "blue blobs" (like dust blobs on LCDs) projected on screen from several W5000s and a W20000.

Light leakage is a concern and it too can be seen on screen in some instances because of the way the vents are aligned.

FW updates - BenQ have been really good here updating FW for free and even arranging pick up and drop off of the units for people - talk about great customer service here!!!

But for the money, this product is still one of the best projectors out there and allowing true HD for that price is something BenQ have done well...


So, still no possibilities for marketing the new lens.?
No, I have the ZEMAX designs now :) Just looking for manufactures that can make that diameter lenses. As soon as I get glass, I will be posting images - lots of them :)


I'm afraid I've been utterly spoilt with cinemascope images..to the point where I'm very reluctant to watch any movies in 1.78...It just seems so boxy!!..almost like the old 4:3 box TV..:R
Scope is great, but not everythig was filmed that way, so in the name of "preserving the art" I will watch the smaller ARs when such films are presented as such.

For me, AR change is easy. I just switch from Letterbox to the 4 x 3 mode. For you, you would also have to toggle the EZ View mode taking the player back to WIDE first, then switching the projector to 4 x 3...

Mark
 

·
HTS Senior Moderator
Joined
·
8,367 Posts
Discussion Starter #80
Where to begin? I don't want to come across as negaitve, but there are many issues with these projectors. BenQ have done the right thing and arranged repair or exchange when faults are reported so well done to them for that. The 8720 was a beast of a projector, and I had just hoped that quality would have been carried into the new models. It seems that was not the case and that legacy ended at W10000.

Some of the issues are simply manufacturing - the have done the right thing by keeping prices low, but QA did drop a touch - it had too. Take the lenses for example. Many (not all, as mine seems to be one of the good ones) have silicon contamination. I am told that this means that the sand used to make the glass was not pure silcon sand, and I have even seen artifacts such as "blue blobs" (like dust blobs on LCDs) projected on screen from several W5000s and a W20000.

Light leakage is a concern and it too can be seen on screen in some instances because of the way the vents are aligned.

FW updates - BenQ have been really good here updating FW for free and even arranging pick up and drop off of the units for people - talk about great customer service here!!!

But for the money, this product is still one of the best projectors out there and allowing true HD for that price is something BenQ have done well...
That is surprising!..I had no idea they were having so many problems..and no FW update is going to fix light leakage problems, or contaminated lens elements..and I can't see BenQ looking for a replacement lens, that doesn't have any contamination!!..

I would have to seriously re-think about getting one, when I upgrade to 1080p..
Pity really, as they looked to be a good choice for Anamorphic projection..:sad:
It's good to hear at least, that BenQ are doing the right thing by their customers..

Have you had this problem of light leaking onto the screen..or does the lens help to block this off.?


No, I have the ZEMAX designs now :) Just looking for manufactures that can make that diameter lenses. As soon as I get glass, I will be posting images - lots of them :)
Probably your best bet would be China..I had the name of a lens manufacturer in China who would make up any type of lens..and in relatively small quantities..I'll see if I can dig it up..


For me, AR change is easy. I just switch from Letterbox to the 4 x 3 mode. For you, you would also have to toggle the EZ View mode taking the player back to WIDE first, then switching the projector to 4 x 3...
Actually it's the same for me...The player stays on WIDE all the time and I just have to press 4 x 3 on the projector remote to go to 16:9..:bigsmile:
 
61 - 80 of 96 Posts
Top