comparison of picture quality of HE and VC Lenses

[zductive]

Could some of you speak about the relative picture quality that you can get from the 2 prism HE lenses made by aussiemorphic or Home theater brothers v. the vertical compression lenses eg., u85 by panamorph.

I understand the tradeoffs between the lenses. But, if I use a 1080p projector and a good screen, will I see enough chromatic aberation or change in focus across the image to make one a lot more desirable than the other.

For guidelines assume a throw distance of 2 or a 104" wide 2.35 screen located about 18 feet from the screen.

The issue about pass through capability by moving the HE lens or leaving the vc lens in place is not a real consideration. But, I don't want to soften the image quality of a 1080p epson or a pearl projector.

[CAVX]

I don't have any 1080 projector screen shots, but I have few 720 shots...

720 DLP with Bru-Ray Disc (http://cavx.blogspot.com/2007/05/look-at-blu-ray-disc.html)

Yes some CA is visible, but that is to be expected from a basic 2 prism lens...

Mark

[zductive]

What I am really looking for is an assessment of whether the CA from the 2 prism lenses causes any discernible pixel level color fringing away from the center of the frame.

I have seen many full frame shots that do indeed look great. But, I haven't seen any close shots. I expect the ca to be similar to the distortion caused by edge enhancement. Its not very visible but its there. The question is - how critical do you need to be before you would notice it.

[CAVX]

What I am really looking for is an assessment of whether the CA from the 2 prism lenses causes any discernible pixel level color fringing away from the center of the frame.

What you see in the shots from the link are as real as it gets. In the case of the Aussiemorphic Lens, both prisms are the same material - BK7 with an AR coating. They therefore have the same RI. In multi element lenses, materials with different RI are used to further reduce the CA, but you pay more for those products.

I have seen many full frame shots that do indeed look great. But, I haven't seen any close shots. I expect the ca to be similar to the distortion caused by edge enhancement. Its not very visible but its there. The question is - how critical do you need to be before you would notice it.

EE and CA are not the same. The CA is a bi-product of bending light (from the lens) and will show up as a colour fringe on high contrast parts of the image edges increasing towards the edges of the image (meaning that is is not always visible all of the time even at the edges), where EE can be see anywhere within the image when ever it is used to enhance the edge of an object...

Mark

[dj7675]

I too am in the same boat... RS1 1080P projector and a Carada BW 52 X 122 inch screen. I think I can get the throw to around 1.8 with the Panamorph U85 lens + lumagen scaler. With the price of the U85 B stock going for $395, is it a good quality lens? How is it compared to the HTB or CAVX models in regards to picture quality? I don't think I want to put the $$$$ for the FE1500 right now and am trying to decide on if I should go with a budget lens, or just zoom the RS1. Any thoughts?

Thanks

Darin

[CAVX]

Any thoughts?

The Panamorph is a VC, where the other two you have mentioned (CAVX and HTB) are HE. Therefore any artefacts that you may see would differ between the two types - CA being just one. With a HE the CA is seen on (high contrast - IE black on white) vertical lines and gets progressively worse towards the edges and I find that generally it is not an issue in the centre 2/3rds of the image.

With a VC, the CA runs the other way, but because the VC also compresses the image, is less likely to be seen. The limitation is that for CIH, you have to leave the lens in place all the time...

Mark