Clear me up: JVC does CIH w/o lens?

Yes, most of the current JVC models will do CIH without the need for a lens using the zoom feature. So long as the throw distance allows it, this means you simply zoom the 16:9 image out to fill the 2.35:1 screen. When doing this without an anamorphic lens the black bars at the top and bottom of the screen will still actually be projected, they just fall off the screen. Because the JVC's have such good black this usually isn't much of an issue.

As to the question of why some still choose to use a lens with the JVC, it's because of those black bars. Without a lens a 16:9 image is still being projected, not a true 2.35:1 image. By using an anamorphic lens you "gain" the extra pixels and lumens that those black bars otherwise consume. This results in roughly 1/3 more pixels being used in the image and brightness increases as well (not sure if it's a full 1/3). If you are trying to fill a very large 2.35:1 screen, or have a lower gain screen those extra lumens can be important to maintain brightness. Others, I'm sure, choose not to sacrifice the pixel resolution.

For reference I use an X30 on a 120" 2.35:1 screen (1.4 gain) at a throw of about 15'. i have about 250Hrs on the bulb and I can still keep the aperture at around -7 in low lamp mode. My room is not a bat cave. To be fair though I haven't checked that this is truly enough lumens to be at 12-14 fl at the screen but it is bright enough for me.

The latest JVCs actually have the ability to do both zoom and VS, so you can project CIH either with or without an A-Lens.

Quite right - the UH480 is an outstanding lens, so if you (the OP) already have one I'd highly recommend keeping it with the RS65. I have an Isco 3 with my RS55 and, given my close seating distance (about 1.2 screen widths), the lack of pixel structure (most notable on high-contrast boundaries) in high-quality material is noticably better with vs. without the lens. My visual acuity is around 20/15, so YMMV depending upon your acuity, seating distance, and type of material.

Given that you already have the lens, the increase in image brightness and CR alone would be worth using it.

Good points all around. I glossed over the fact that the OP already has a lens. The JVC's can indeed make use of the lens and would likely benefit from the increased brightness and vertical pixels.

I have the New RS45 and prefer the image with the lens in place it is just sharper and cleaner image.

Given I'm about to buy a Panamorph UH480 A-lens for my system, I'm wondering how much brightness increase you actually get using this lens on a JVC projector.

I have the JVC RS55 projector with it's E-shift, hence I have no need for added pixel density (I never saw a need even with my previous RS20 projector). But since my room is a bit depth challenged - my throw distance is only 13 1/2 feet from the screen, max - I've always considered adding an A-lens simply to get an even wider scope image.

As I remember from the controversies about the brightness advantage of adding A-lenses, some projectors increase light output as you zoom out the lens - essentially giving you the same effect as adding an A-lens to a smaller zoomed image. And in some projectors it ends up being a "wash" in terms of actual brightness difference between zooming out or using an A-lens.

The JVC projectors apparently increase brightness when zooming larger, so I'm wondering in practical terms if there actually will be a visible difference in a 124" wide image on my screen using the A-lens vs zoomed.

Thanks.

Perceived brightness prob negligible the projector produces more brightness as you zoom out for the same picture size with shorter throw ratio but if the throw stays the same and zoom the image that much bigger it does eat up some light. Where you are maxed on throw you could leave a smaller image and gain contrast and sharper image while keeping the light output constant.

My wife is extremely happy (which is all that counts, of course) with my 55 doing CIH on a 136" Carada BW. The 55 is 17ft from the screen. We sit 11 ft from the screen. Yes, I know everything says that won't work, but it does and looks awesome, and we like the screen that close. Not the easiest configuration for the projector to handle, but even then I never use High Lamp on 2D images and generally don't on even 3D Scope stuff. Again, if my Doubting Thomas Wife brags about it... it's pretty good. And we've had some pretty good hardware for her to compare to, prior to this HT thing happening. Nice not to have to invest in the A lens. More money for other HT stuff!

Thank you. If I understand correctly then, since my throw will remain the same (as is typical for any set up with an A-lens) I should see some measure of higher brightness using the A-lens for my widest images, vs zoomed-only to the same size.

That you should and slightly better contrast at the same time.

Update Lens tested with was an ISCO III.

A UK dealer (who sells panamorph) did some A/B comparisons with joe public JVC X30 and all said no need for the A-lens.

http://www.avforums.com/forums/proje...quality-3.html

Here's the ACTUAL quote:


Regarding the brightness issue - without a direct side-by-side comparison, the difference in brightness between an anamorphic lens setup and a zoom setup may not be readily apparent, depending upon the aggressiveness of the iris that's engaged when the projector's zoom is used. However I have yet to see a single report of a projector with an iris so aggressive that one would get equal or more lumens by zooming as compared to using an anamorphic lens.

The poster didn't really comment on any of the other myriad of variables that can make the difference between a lens and zooming apparent (or not): screen texture, quality of the material being watched, viewing distance, visual acuity, image brightness, etc. Lump on top of that that the effect of all of these variables may be readily apparent to an enthusiast but not a casual observer...and what we can conclude from the above quote is of little to no use.

Understand that I'm not for or against one CIH method or another; different budgets, personal preferences, design constraints, and other variables can drive an individual to favor one method over another. However the quote above is anything but definitive as to which method is "better" - not that such a black and white statement could be made in the first place.

Anamorphic lens vs lens shift/zoom

Anamorphic lens pros
- Higher pixel density (but not higher resolution/more details since image is just scaled)
- Slightly higher light output (extra lens will also "consume" some light)

Shift/zoom pros
- No extra lens related image distorions
- No need for aditional lens (Saves a bunch of $)
- No manual handling when moving between 16:9 4:3 2.40:1 (except push button for aspect change)
- No need for curved screen (cheaper)
- No issues for 3D (related to lens distortion)

Both solutions cons:
- Subtitles might land off screen depending on material (easily solved with i.e. Oppo BDP-93/95 and/or HTPC)


My preferance: JVC DLA-X30 and a 2.40:1 screen

You missed another pro which is higher contrast retainment (esp with the jvcs) since you're not dropping your throw as significantly when zooming. Before when I was zooming I would actually physically move the projector a few feet back just to minimize zooming as much as possible. Maybe I'm just sensitive to the effect but I can could clearly see the lost of contrast going from min to wide, and I wouldn't call it trivial by any stretch.

I am in the design phase of new contruction that will include a new home theater (woohoo!). My wife has given me pretty much cart blanche to pursue whatever design I would like. I will most likely be looking at about a 16'X26' space. I would like to get to about a 130"-140" CIH diagonal screen. I am not sure it is realistic in terms of light output.

What size diagonal screen is the point of diminishing return in terms of light output for an RS45 when using an anamorphic lens in a totally light controlled room?

Thanks,

Willie

So it has a memory function?

Hi All,

Yes the JVC's have lens memory. You can do CIH with any projector and process it for 16:9 HD broadcast sources with a Lumagen processor. That's what I do with my Samsung 900B. The image is superior to one using an outboard lens due to the lack of another piece of glass in front of the primary lens and no addtional processing.

Good to know.