Constant Image Height 2.35:1

[AnalogueMan]

When reading about the benefits of CIH here I needed no convincing.

I've seen the same principle at work on my Loewe CRT TV when using its 16:9 mode versus 4:3 with letterboxing. The resolution difference is about as dramatic as SD versus HD television on a 720p projector. A projector with 2.35 cinemascope DVD and anamorphic lens is much the same thing.

I considered the Aussiemorphic lens described here (all power to Mark Techer), but my pj is set up each vewing on a flimsy folding wooden stool, http://somethingindifferent.blogspot.com/, so I wanted a minimal size/weight solution. As a toe in the water, I ordered two trophy crystal prisms discussed in www.diyaudio.com/forums.

http://www.evright.com/showproduct.asp?P=CB8A

It's very simple to set up. I just plonked them in front of my AE700, put on a 2.35 DVD, toggled the PJ aspect, and fiddled briefly with the prism positions and angles.

My initial impression was the image looked good, with tolerable rectangular distortion, chromatic aberration which was not distracting, and comparable sharpness to direct view.

However, the image seemed to take a hit in terms of brightness. On paper, the image should be brighter of course. The naked mounting of the prisms provided a clue. Three ghost images were present and comfortably viewable on the left, right, and rear walls, due to reflections from the prisms. My experience with astronomy optics and the fetish with that gear for fully multicoated lenses on all surfaces suddenly made sense. The prisms were uncoated glass, and as a result I was leaking a lot of light.

The other surprise was the theoretical vertical resolution increase didn't jump out at all. In fact, I had some trouble convincing myself it was there. And I know that the same comparison with my CRT in 16:9 anamorphic mode is night and day, as is 576p SD versus 720p HD for me.

Worse still, when viewing one of the Lord of the Rings DVDs, the subtitles (for elf talk etc) appeared in the black horizontal bars, so you lose them if you go anamorphic. (Does this mean that these DVDs are just letterboxed 16:9?)

I'll keep experimenting, and post any further findings. I had limited time and it was getting late (isn't always with HT? :-) Comments, relevant threads, articles etc welcome.

[AnalogueMan]

PS

Bare glass loses about 4% per surface due to reflection, therefore total loss with 4 surfaces is 96%^4 = 85%. Brightness increase = 9/(16/2.35) -> 32%.

Therefore, net brightness increase should be ~ 17% - absorption/scattering losses (small?). I.e., it still should look brighter...but it really doesn’t. I need to double check with a light meter or camera with fixed exposure.

Actually, that 4% figure applies for perpendicular incidence. In this application the sharp angle of incidence may be further increasing this loss. Must try Fresnel calcs http://en.wikipedia.org/wiki/Fresnel_equations

Incidentally, even basic single layer coating such as magnesium fluoride (MgF2) can cut reflection to 1% http://en.wikipedia.org/wiki/Anti-reflective_coating

Anyone know who does this sort of optical coating? I’m guessing vacuum deposition on large chunks of glass aint cheap.

[CAVX]

Anyone know who does this sort of optical coating? I’m guessing vacuum deposition on large chunks of glass aint cheap.

Yes been down that road...

Mark

[mgrobins]

as long as I can block the ghost images on mine I think I'll be happy. My pj has more brightness than I need thankfully.

Interesting read though..... let us know how you go with your calcs (I make a concerted effort to stay away from mathematics nowadays lol).

After all of the analysis do you actually like the change to CIH?

[Foggy]

Mark has gone to some effort to absorb stray reflections with his Aussiemorphic Lens kit, and it certainly makes a huge difference over the "naked" prisms.

As far as subtitles go, this is something that is at the mercy of the DVD player manufacturers. They can choose to place subtitles wherever they like on the screen, and some even give you options of where you want to place them.

The cost of optical non-reflective coating would make the final solution prohibitive in terms of cost. I think it's unreallistic to expect perfection in this price range, as the world of optics requires plenty of $$$$'s to achieve a high level of precision.

Overall, the effect and impact of a CIH setup is not something that is obvious when looking at numbers and specifications, it is something that needs to be experienced.

[Foggy]

http://www.evright.com/showproduct.asp?P=CB8A

These guys are crooks!!

Just over a month ago, they were selling these prisms for around $50 each. Since they realised it's for HT they have doubled their pricing with no justification. This is the main reason why I started the powerbuy, so that we could get enough numbers to achieve some slight price relief by virtue of a bulk order.

Unfortunately they are currently sole importer of these prisms, so they think they can get away with it.

There are other, cheaper prisms available, but they are wildly variable in their quality and specification, and thus not suitable for any sort of optical application such as CIH.

[AnalogueMan]

These guys are crooks!!

Just over a month ago, they were selling these prisms for around $50 each. Since they realised it's for HT they have doubled their pricing with no justification. This is the main reason why I started the powerbuy, so that we could get enough numbers to achieve some slight price relief by virtue of a bulk order.

Unfortunately they are currently sole importer of these prisms, so they think they can get away with it.

There are other, cheaper prisms available, but they are wildly variable in their quality and specification, and thus not suitable for any sort of optical application such as CIH.

I did notice that after buying a pair a week ago for about $80 each, the price had jumped to the current $104.

Crooks? Nah, just free-marketeers. You're free to import the same prisms and sell them at a "fair" price.

[AnalogueMan]

Mark has gone to some effort to absorb stray reflections with his Aussiemorphic Lens kit, and it certainly makes a huge difference over the "naked" prisms.

What is the huge difference? The reflections I'm seeing with naked prisms don't hurt the screen image, apart from light loss.

Adding a non-reflecting housing does nothing to reduce loss, and because it will not be perfectly non-reflecting, it will potentially add secondary reflections which will show up in the screen image. At least the distracting ghost images on the walls disappear though.

As far as subtitles go, this is something that is at the mercy of the DVD player manufacturers. They can choose to place subtitles wherever they like on the screen, and some even give you options of where you want to place them.

Is it the DVD player? On the same player with a different DVD, the subtitles were in the picture. It seems to be disk dependent.

The cost of optical non-reflective coating would make the final solution prohibitive in terms of cost. I think it's unreallistic to expect perfection in this price range, as the world of optics requires plenty of $$$$'s to achieve a high level of precision.

Agreed.

Overall, the effect and impact of a CIH setup is not something that is obvious when looking at numbers and specifications, it is something that needs to be experienced.

I'll make up a housing and watch few movies right through before passing final judgment. I must say, removing the distraction of the black bars alone is very nice.

[Foggy]

What is the huge difference? The reflections I'm seeing with naked prisms don't hurt the screen image, apart from light loss.

Adding a non-reflecting housing does nothing to reduce loss, and because it will not be perfectly non-reflecting, it will potentially add secondary reflections which will show up in the screen image. At least the distracting ghost images on the walls disappear though.

Yes, you're right in that the image quality or sharpness won't change, but as you said the improvement is in not seeing the reflections. Considering the objective of CIH (i.e. to remove the black bars), having other stray light being reflected around the room detracts from the overall effect.

Is it the DVD player? On the same player with a different DVD, the subtitles were in the picture. It seems to be disk dependent.

The HTPC guys are often discussing locating the subtitles wherever they like using Zoomplayer & FFDshow, so I'm fairly certain that it can be done in the decoding of the DVD. Perhaps there's a default position specified by the production house, but it can be overidden by the player.

[CAVX]

The HTPC guys are often discussing locating the subtitles wherever they like using Zoomplayer & FFDshow, so I'm fairly certain that it can be done in the decoding of the DVD. Perhaps there's a default position specified by the production house, but it can be overidden by the player.

And players like the Samsung HD-950 have ezview that shift the subtitles up...

Mark

[RodN]

These guys are crooks!!

Just over a month ago, they were selling these prisms for around $50 each. Since they realised it's for HT they have doubled their pricing with no justification. This is the main reason why I started the powerbuy, so that we could get enough numbers to achieve some slight price relief by virtue of a bulk order.

Unfortunately they are currently sole importer of these prisms, so they think they can get away with it.

There are other, cheaper prisms available, but they are wildly variable in their quality and specification, and thus not suitable for any sort of optical application such as CIH.

I hate that......

You should check out the pro-audio market Foggy. Many of their amps would put some HT amps to shame and they're a quarter of the cost. Same with cables..... same with tradies.... etc

[gobberon]

Yes, you're right in that the image quality or sharpness won't change, but as you said the improvement is in not seeing the reflections. Considering the objective of CIH (i.e. to remove the black bars), having other stray light being reflected around the room detracts from the overall effect.

The HTPC guys are often discussing locating the subtitles wherever they like using Zoomplayer & FFDshow, so I'm fairly certain that it can be done in the decoding of the DVD. Perhaps there's a default position specified by the production house, but it can be overidden by the player.

There are a couple of methods in use. The subs are actually bitmaps. So you can either run them though an OCR and use the text files or split the bitmaps out of the VOB stream and rescale and reposition wherever you want to place them - if you have a HTPC or a Samsung of course.

[mgrobins]

I'm really hoping that the importer of the lenses have their greedy attitude come back to bite them in the arse hard. I'd like to see someone get a deal with the manufacturer and bypass them.

No one will complain about a business making money but profiteering is just bad form. Maybe they also run petrol stations??? :/

Mark showed me a way to get around the subtitle issue on my CIH setup. Basically I still get the correct ratio but end up viewing the movie with black bars again. Given how rare it is to require them I'm happy with the compromise as Marantz don't believe in having cool features on their high end dvd players apparently . Ez-view is a simple yet really handy function. Maybe if CIH takes off it will become more available.

[c912039]

Ive been reading up on the Panamorph UH380 and power sled. I was shocked at how much each of these units costs.

I started doing some calculations on home much it would cost to set up a 1080p projector, together with a CIH lens with aspect ratio change (2.35:1/16:9) such as the Panamorph Power Sled.

It works out that for less than the cost of say a Mitsubishi HC5000 1080p projector, Panamorph UH380 and Power Sled, you could buy the HC5000, Mark's CAVX lens ... AND a second HC5000 projector (without CAVX lens) just for playing back 16:9 media.

IE 2 HC5000's sitting side by side - one with the CAVX lens used for playing back 2.35:1 material, and the other for playing back 16:9/4:3 material.

And you would end up with change in your pocket as well, not to mention how wicked the setup would look in the HT room!

Regards

David

[Foggy]

I like the way you're thinking David

I was thinking about doing a similar thing with motorised screens, it's cheaper than motorised masking options.

[The_Preacher1973]

It works out that for less than the cost of say a Mitsubishi HC5000 1080p projector, Panamorph UH380 and Power Sled, you could buy the HC5000, Mark's CAVX lens ... AND a second HC5000 projector (without CAVX lens) just for playing back 16:9 media.

IE 2 HC5000's sitting side by side - one with the CAVX lens used for playing back 2.35:1 material, and the other for playing back 16:9/4:3 material.

And you would end up with change in your pocket as well, not to mention how wicked the setup would look in the HT room!

Regards

David

It might be even more cost effective than that because after reading reading through the HC5000 manual it's not very clear whether or not it will do the vertical stretch (I would lean towards the fact that it can't - can any owners on here verify please?).

As such, you'll need to add another $2000 at least for something like a Lumagen HDP to do the required vertical stretch.

Also, a lot of us already have a projector. So maybe you don;t need to buy two anyway.

So following on from both yours and Foggy's post regarding masking, a good solution would be to buy a 1080P projector and keep your existing 720P projector. Use a fixed screen 2.35:1 screen that can be covered up by curtains and have a 16:9 screen drop down in front of it. One porjector is set up for the 2.35:1 screen, the other is set for 16:9.

Doing things this way, you'd probably get the best possible result using something like an 8720 with the aussiemorphic lens for 2.35:1 (as it has the vertical stretch built in and as previously discussed you won't benefit as much from an anamorphic lens with a 1080P PJ as it has to upscale above the resolution of the source) and use the HC5000 for 1.85:1/16:9 viewing. As the HC5000 has excellent processing of interlaced video material , it would probably be more suited to day to day TV/off air broadcasts.

[Foggy]

It might be even more cost effective than that because after reading reading through the HC5000 manual it's not very clear whether or not it will do the vertical stretch (I would lean towards the fact that it can't - can any owners on here verify please?).

Not an owner Preach, but I had a very careful read of the the HC5000 manual the other day because another member asked me the same question, and I'm certain that it doesn't do the appropriate vertical stretch for CIH.... although, it wouldn't be the first time that the manual doesn't match the firmware :fingers crossed:

As such, you'll need to add another $2000 at least for something like a Lumagen HDP to do the required vertical stretch.

Also, a lot of us already have a projector. So maybe you don;t need to buy two anyway.

So following on from both yours and Foggy's post regarding masking, a good solution would be to buy a 1080P projector and keep your existing 720P projector. Use a fixed screen 2.35:1 screen that can be covered up by curtains and have a 16:9 screen drop down in front of it. One porjector is set up for the 2.35:1 screen, the other is set for 16:9.

Doing things this way, you'd probably get the best possible result using something like an 8720 with the aussiemorphic lens for 2.35:1 (as it has the vertical stretch built in and as previously discussed you won't benefit as much from an anamorphic lens with a 1080P PJ as it has to upscale above the resolution of the source) and use the HC5000 for 1.85:1/16:9 viewing. As the HC5000 has excellent processing of interlaced video material , it would probably be more suited to day to day TV/off air broadcasts.

OMG... how on earth would I ever get the wife to understand how to use that!! ....I like it

[The_Preacher1973]

OMG... how on earth would I ever get the wife to understand how to use that!! ....I like it

Hey, if I can teach my wife how to use a CRT for her karaoke parties, then the aforementioned setup should be a breeze!

OK. I had to write down step by step instructions for her to follow, but in fairness to her, there were quite a few remotes to chose from:

My Remote Collection

[norpus]

I like the way you're thinking David

I was thinking about doing a similar thing with motorised screens, it's cheaper than motorised masking options.

Me too Foggy - great minds and fools...

[benthx]

Not an owner Preach, but I had a very careful read of the the HC5000 manual the other day because another member asked me the same question, and I'm certain that it doesn't do the appropriate vertical stretch for CIH.... although, it wouldn't be the first time that the manual doesn't match the firmware :fingers crossed:

OMG... how on earth would I ever get the wife to understand how to use that!! ....I like it

Hey Fogster and Co.

The Mit hc5000 doesnt do the the required stretch. I looked at one in operation and the guy in the store didnt really understand. I told him give me the remote and lets explain. We both concluded after going throught the settings etc... it doesnt have this ability.

Vertical stretch I can do that I only wished other PJs could do this as well but perhaps they are asleep.

Ben

[CAVX]

Hi,

Thanks to mgrobins for the use of his room today. It was good to meet Bocca as well.

With all the earlier chat about "stray light and no extra resolution, check THIS LINKout...

Mark

[Bocca1503559681]

Hi,

Thanks to mgrobins for the use of his room today. It was good to meet Bocca as well.

With all the earlier chat about "stray light and no extra resolution, check THIS LINKout...

Mark

WOW, Mark the pics look terrific and thanks so much to you and mgrobins for the chance to appreciate first hand wot will certainly now be my set up.

I am very impressed with CIH now having experienced first hand and can't wait to get the pj and screen from oztheatrescreens and of course your am' lens

thanks again to you both for your time and sharing your knowledge

bocca

[CAVX]

WOW, Mark the pics look terrific and thanks so much to you and mgrobins for the chance to appreciate first hand wot will certainly now be my set up.

I am very impressed with CIH now having experienced first hand and can't wait to get the pj and screen from oztheatrescreens and of course your am' lens

thanks again to you both for your time and sharing your knowledge

bocca

More than welcome Bocca

Mark

[gobberon]

More than welcome Bocca

Mark

The pics coming out of the Benq look amazing and the widescreen looks great .. like in a theater, I'm expecting to see someone's silhouette walk across the bottom.

[CAVX]

The pics coming out of the Benq look amazing and the widescreen looks great ..

Yes I was very impressed with how simple it was, so added a small bit to the title so it now reads "Beauty And The Beast - A Perfect Match"

Mark