I'm assuming that they only require the housing upgrade because the screw configuration of the FE does not match their old housings. If we were to build our own housing from scratch, we could easily accomodate the screw config by tapping our own holes. But, I still agree with you, I would rather find a complete diy method (as long as it is cheaper)😀 .
Not to put a spanner in the works, but I am going to hold off until I get my optic coated prisms and then go from there...
I honestly think that we need to look at the surface of our prisms - ie right now they are flat...
Mark
I honestly think that we need to look at the surface of our prisms - ie right now they are flat...
Mark
WAAAAAAAAAAAA Mark put a spanner in the works!
Just kidding...you're implying the prisms should have a curved surface?
Bud
Just kidding...you're implying the prisms should have a curved surface?
Bud
front lens element
Now that our prisms are finished I am thinking about improvements, too. I am intrigued with the possibility of a diy front lens element.
My brother-in-law is a retired optical systems engineer with some NASA experience. I will ask him tomorrow about his thoughts on the cost and viability of a front focusing lens. I already checked out a couple of USA based lens manufacturers and found one or two that will produce small quantity production runs. I have no idea about the cost effectiveness of this approach yet. It might be cheaper to buy and adapt a Prismasonic lens. If so, I will probably pass on it.
Anyway, I'm with you guys...and I have the list of avs group purchasers from the L&L dealie in case we get that far with another lens element.
Richard G.
Now that our prisms are finished I am thinking about improvements, too. I am intrigued with the possibility of a diy front lens element.
My brother-in-law is a retired optical systems engineer with some NASA experience. I will ask him tomorrow about his thoughts on the cost and viability of a front focusing lens. I already checked out a couple of USA based lens manufacturers and found one or two that will produce small quantity production runs. I have no idea about the cost effectiveness of this approach yet. It might be cheaper to buy and adapt a Prismasonic lens. If so, I will probably pass on it.
Anyway, I'm with you guys...and I have the list of avs group purchasers from the L&L dealie in case we get that far with another lens element.
Richard G.
Mine didn't turn up today (delivery company's fault, not manufacture), so how long before you can start to document the benefits?
I am told tomorrow, so we'll see...
Mark
I am told tomorrow, so we'll see...
Mark
4 prism lens
Mark, Can you tell us how you are going to orient the prisms, i.e. all four horizontal or two horizontal and two vertical? Any particular spacing or angles that you will use? Are you trying to do more than just horizontal expansion?
hnshaw
Mark, Can you tell us how you are going to orient the prisms, i.e. all four horizontal or two horizontal and two vertical? Any particular spacing or angles that you will use? Are you trying to do more than just horizontal expansion?
hnshaw
In this case, each prism is thin (custome ground for me) and two fit in the same place as one regular prisms.
All 4 were therefore horizonal...
Mark
All 4 were therefore horizonal...
Mark
Just FYI, I have ditched the 4 prism design and gone back to a 2 prisms lens as I found it gave better images.
What you are now seeing in the link is the latest new 2 prisms lens and screen shot...
Mark
What you are now seeing in the link is the latest new 2 prisms lens and screen shot...
Mark
Yes I did, and it didn't really make a difference as I an now told (actually this mentioned a while back in this tread) that K9 is BK7...
Mark
Mark
Reducing CA
Hi All,
I am wondering if CA can be reduced by using prisms with different refractive indexes. This has been discussed earlier (much earlier) in this thread - see post #45.
BK7 is (or is near to) crown glass and crystal has a higher RI which varies depending on the lead content from around 1.6 to 2.0.
So by using a BK7 prism with a crystal trophy prism a lens with reduced CA should be achieved.
Has anyone tried this?
Hi All,
I am wondering if CA can be reduced by using prisms with different refractive indexes. This has been discussed earlier (much earlier) in this thread - see post #45.
BK7 is (or is near to) crown glass and crystal has a higher RI which varies depending on the lead content from around 1.6 to 2.0.
So by using a BK7 prism with a crystal trophy prism a lens with reduced CA should be achieved.
Has anyone tried this?
Yes I did try this - one optically coated BK7 prisms + a standard cystal prism. The result was the same. Earlier (not too sure of the post number) the material each trophy prisms was made from was discussed. It seemed that we were under the impression that the material was K9. I have since been informed that K9 is BK7, so would have the same RI.
Are you suggesting that differnt batches might have differnt RI due to the lead content?
Mark
Are you suggesting that differnt batches might have differnt RI due to the lead content?
Mark
Hi Mark,
That's exactly what I was thinking.
The prisms are advertised as crystal which to me means lead cyrstal not crown glass (BK9 and K9).
If anyone as crystal prisms that are made of lead crystal, they will have a higher refractive index.
Lead crystal is a type of flint glass and BK7 (or K9) are types of crown glass.
Using one of each type of prism in the lens should form an achromatic doublet. Ideally the prism angles should be calculated but it might still make a worthwhile difference in reducing CA.
Greg
That's exactly what I was thinking.
The prisms are advertised as crystal which to me means lead cyrstal not crown glass (BK9 and K9).
If anyone as crystal prisms that are made of lead crystal, they will have a higher refractive index.
Lead crystal is a type of flint glass and BK7 (or K9) are types of crown glass.
Using one of each type of prism in the lens should form an achromatic doublet. Ideally the prism angles should be calculated but it might still make a worthwhile difference in reducing CA.
Greg
massillonplaque prisms
Hi Guys,
I just came across this thread today and have been reading all the pages. I am going to order 4 massillonplaque prisms and test it on my Sharp XZV-12000 Mk II projector. Currently I have a DIY prismasonic lens (spent over US$800), it is great, but they are small lenses (works well with Sharp, but may not work with other projectors) and there are some CA.
Currently I am looking to upgrade my projector to Optoma HD81, so my question to DIY lens experts here is if anyone tested anamorphical expansion of 1080p material (HD-DVD or Blu-Ray) using these massillonplaque prism (ideally 4prism lens).
Also I am building a 14foot wide 2.35 Curved screen. Just received 'b-a deals' 16'x9' screen material.
Any latest info ordering massillonplaque prisms?
Thanks
Hi Guys,
I just came across this thread today and have been reading all the pages. I am going to order 4 massillonplaque prisms and test it on my Sharp XZV-12000 Mk II projector. Currently I have a DIY prismasonic lens (spent over US$800), it is great, but they are small lenses (works well with Sharp, but may not work with other projectors) and there are some CA.
Currently I am looking to upgrade my projector to Optoma HD81, so my question to DIY lens experts here is if anyone tested anamorphical expansion of 1080p material (HD-DVD or Blu-Ray) using these massillonplaque prism (ideally 4prism lens).
Also I am building a 14foot wide 2.35 Curved screen. Just received 'b-a deals' 16'x9' screen material.
Any latest info ordering massillonplaque prisms?
Thanks
Re: massillonplaque prisms
Welcome to the Forum 🙂 What Prismasonic model have you got? You've mentioned some CA, so I have to assume H600D as the H1200D didn't have much if any CA when I was given the oppertunity to test it. I like their design, but it is a shame the prisms are just 85mm high.
The mp prisms, are they the ones that are 1.5"?
Yes I have, but not with a 4 prisms lens. The interesting thing I found with the 1080 projector was that the pixel structure is so fine, it isd hard to tell if the image is being blured by the prisms. On 720 projectors, you can usually still see the pixels, and can adjust the sharpness of the image with an on screen menu...
HERE is a link to some screen shots I took using Blu-ray Disc through a Vantage scaler and projected by the Sharp Z10 000 720 DLP.
Remember this is only a two prisms lens, so yes some CA is visible. The image was about 10 feet wide...
14 feet is a big screen. The Sharp should light that OK though...
There is some feed back to the guys that got their prisms coated on AVS. One guy has even posted soem very impressive screen shots as well...
Mark
PrabhatB said:
Welcome to the Forum 🙂 What Prismasonic model have you got? You've mentioned some CA, so I have to assume H600D as the H1200D didn't have much if any CA when I was given the oppertunity to test it. I like their design, but it is a shame the prisms are just 85mm high.
The mp prisms, are they the ones that are 1.5"?
Yes I have, but not with a 4 prisms lens. The interesting thing I found with the 1080 projector was that the pixel structure is so fine, it isd hard to tell if the image is being blured by the prisms. On 720 projectors, you can usually still see the pixels, and can adjust the sharpness of the image with an on screen menu...
HERE is a link to some screen shots I took using Blu-ray Disc through a Vantage scaler and projected by the Sharp Z10 000 720 DLP.
Remember this is only a two prisms lens, so yes some CA is visible. The image was about 10 feet wide...
14 feet is a big screen. The Sharp should light that OK though...
There is some feed back to the guys that got their prisms coated on AVS. One guy has even posted soem very impressive screen shots as well...
Mark
DIY prisms
Hi Mark,
Thanks, my prismasonic is a DIY kit lens, probabaly model no. H700. These prisms are merely 2.5x2.5 inch (small) and 3x4 inch (big)and they are AR coated. On the other hand, the smallest mp prisms are 4x6 inch. I also read about the AVS thread and interested doing it. But I think I want to try 4prism assembly and mp prisms are cheaper alternative. I will try to reduce the AR in some other method.
I wish Bud or someone can post side/side pictures of CA using 2prism and 4 prism. I know 4prism makes a lot of difference.
Mark, thanks for the link - your aussiemorphic lens used with 1080p source works great with very neglible CA (as per the photos). Regarding CA, with best adjustment my DIY Kit lens can match yours, but cannot surpass it. The issue is for a screen as wide as 14feet, you oughta get some CA with two prism lens, hence my quest for 4 prism lens.
Sharp is pretty good lighting up this huge screen size and picture quality of this projector is really great.
Hi Mark,
Thanks, my prismasonic is a DIY kit lens, probabaly model no. H700. These prisms are merely 2.5x2.5 inch (small) and 3x4 inch (big)and they are AR coated. On the other hand, the smallest mp prisms are 4x6 inch. I also read about the AVS thread and interested doing it. But I think I want to try 4prism assembly and mp prisms are cheaper alternative. I will try to reduce the AR in some other method.
I wish Bud or someone can post side/side pictures of CA using 2prism and 4 prism. I know 4prism makes a lot of difference.
Mark, thanks for the link - your aussiemorphic lens used with 1080p source works great with very neglible CA (as per the photos). Regarding CA, with best adjustment my DIY Kit lens can match yours, but cannot surpass it. The issue is for a screen as wide as 14feet, you oughta get some CA with two prism lens, hence my quest for 4 prism lens.
Sharp is pretty good lighting up this huge screen size and picture quality of this projector is really great.