16:9 Screen Vs. 2.37:1 CIH Screen

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..

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

takumi said:

scaler? vertical stretch? i have a lot to learn.

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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..

Prof. said:

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.!!

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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 ) 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

Mark Techer said:

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

Click to expand...

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.

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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.

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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.

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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 ) that is under development right now and will use achromatic doublets.

Click to expand...

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.

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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.

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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...

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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.

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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!!

Prof. said:

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..

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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..

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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:

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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..

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Can't have everything

I'm very interested to see the pics of that lens when it's finished..

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There will be plenty of pictures, don't worry about that

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..

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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!!

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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

Prof. said:

I've only ever seen good reviews..What are the negative aspects?

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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.?

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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

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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