clckworang

If it makes you feel any better, I still don't really know what those terms mean but am really happy with my projector's performance.

Joe Schmoe

Good to know. I'm probably overthinking the whole thing.

Spiky

You need to get a perfect square-cornered picture on the screen. These 2 things can help that happen by adjusting the shape/positioning of the picture. Lens shift does it optically, keystone does it digitally. Optical is far better, of course. Keystone generally damages the pic and the resolution. BTW, "Lens Offset" is another key term in this.

Here's the deal: A projector with no lens offset or lens shift (or keystone) would need to be placed in the exact center of the screen both vertically and horizontally. Now, that would be a horrible place to put the projector, imagine the problems with it hanging 4.5' off the ground in the middle of the room. So they generally all have offset, meaning the picture is projected through the lens at an angle so it should be positioned near the top or bottom of the screen. Shift allows it to have a range of position possibilities.

If you look at setup diagrams in manuals, they show the angles necessary. More expensive PJs generally have better options, or for the cheaper models (sub $2K), LCD tends to have more options than DLP. Not exactly sure why that is, but it means LCD is better for certain rooms.

kvrdave

Spiky pretty much nails it. I have my projector on the ceiling and it projects onto a 122" screen about 13' away. Without lens shift, the image produced would be trapezoid in shape with the bottom being wider than the top. That trapezoid is referred to as the keystone effect. With a flip of the button on the remote the projector will digitally widen out the top of the screen until you have a rectangle. But in doing that you are really stretching out the pixels at the top. You likely wouldn't notice it a great deal, but you are dropping your overall resolution.


Lens shift, on the other hand, has the ability to take the rectangular image that would be directly in front of a projector, and let you shift it to where you want it without any loss of resolution. Some shift both horizontally and vertically, but vertical is the most common.



A 100% shift would be what you see in the first vertical shift picture. The top of the true center can be shifted to the bottom. Effectively, if you could end up with 3 full screens, you'd have 100% shift. The horizontal shift in the bottom part of the picture would be 50% shift, where the left (or right) side of the true center picture can shift to the middle. So if you get room for 2 full pictures, it is a 50% shift.

The LG projector has a lens shift of +/-70%. That make sense?

kvrdave

Oh, and I forgot to use the coupon code "super" for $50 off. I could call, but probably won't.

Spiky

That picture reminds me. The screen and projector should be perpendicular to each other. The screen should be perfectly vertical and the projector perfectly horizontal. So that picture showing keystone would be a poor setup, with the projector aiming downward. That's what caused the need for keystone.

When you see all these diagrams and have people try to explain it to you, it can seem a lot more complicated than it is. It's true there are several rules to follow since the PJ must be in a certain place to project properly and you have to consider all 3 dimensions of both the screen and PJ, but if you look at them one at a time, it isn't that bad. A lot of these are pretty obvious, really:

• Screen should be perfectly vertical, use a level.
• PJ should be perfectly horizontal, use a level.
• PJ must be a certain distance from the screen depending on how big the screen is, use a calculator for your model to figure out the potential zoom range you have.
• Lens must be centered horizontally on screen, many PJs have no horizontal shift, so it must be perfectly centered. Others have a bit of shift range, but not usually very much. Note that some PJs have the lens over to one side, not in the middle. That can make the measuring a little trickier. It means the mount will not be centered on the screen.
• Lens must be vertically within the PJs shift/offset range. Some low end DLPs have no shift at all. Their lens must be placed at a specific height in comparison to the screen, and the manual will give this info. In contrast, the Panny AExxx series has a large lens shift, you probably wouldn't even need to worry about measuring, it will fit anywhere, any room.

If you have some tight room dimensions, it is best to look at these beforehand to make sure the PJ you want will fit. The DLPs with no shift don't fit in my room, for instance. I only have a 7' ceiling, and many of them would have to be 6-10" above the screen to work. I just don't have space for that unless I want a smaller screen, which kinda defeats the purpose.

Spiky

You are not helping my wallet!

kvrdave

Joe Schmoe

Thank you, kvrdave and Spiky, for the info! Sounds like lens shift is very important. I guess that means consumers who buy projectors without it either have their projector lined up with the screen to get a perfect rectangular picture or they live with a trapezoidal-shaped picture (or with compromised resolution due to keystone). I'm a stickler for picture quality, which is why I'm thinking of selling my 73" Mits DLP 3D TV. The 1080p resolution is cut in half in 3D mode and it drives me nuts, so most likely if I were to get a projector without lens shift I'd be unhappy with the image quality. I was thinking of getting the Optoma HD33 because I already own 4 pairs of Optoma DLP-link glasses, but now I'm going to consider some higher priced DLP projectors with lens shift. Hopefully, the Optoma glasses will work with other brands of DLP projectors.

kvrdave

If you are a stickler, you'd want lens shift. My first projector (not HD) didn't have it and I had to use the keystone fix. It wasn't awful, but there are so many good choices with lens shift that it is hard to imagine not getting it unless you are looking to stay under $1,000. If you go with DLP, make sure you check it out live rather than blind buy. Some people get a rainbow effect with them where they essentially see rainbows (hence the name). I could see it on my old dlp if I violently shook my head from side to side, but that was the only time. But, in general, DLP is better than LCD, in my opinion.

Joe Schmoe

I know some people see the rainbow effect on DLP TV's. I don't (thank goodness), so I hope that means I won't see it on a DLP projector. Why do you like DLP over LCD?

I started looking at Mitsubishi's HC7800D DLP projector since I already own 4 pairs of DLP-Link glasses. It has H & V lens shift and V keystone, manual zoom and focus, 1500 ANSI and a 100,000:1 contrast ratio. Mitsubishi claims its 2D-3D conversion is better than the average conversion algorhythm, and it sells for $2,799 at Amazon. It all sounded great until I read that it uses proprietary glasses that don't come with the projector, and one pair sells for $200. What a joke! Mitsubishi doesn't sell glasses for their DLP TV's, but now they make exclusive glasses for their projector?? If Mitsubishi's glasses are the only ones that will work with the HC7800D, then I'll cross this projector off my list.

kvrdave

DLPs seem to get better reviews overall, so my preference to them probably just has to do with jealousy. But they tend to be more expensive, and for the $3,000 and under projector, there doesn't seem to be a real advantage. They "shine" in their black levels, which used to be a pretty big issue with LCD, but hasn't been for several years. So even though I talk big about the DLP, my last 2 have been LCD and I have been blown away by them.

I love Amazon, but make sure you check with projectorpeople.com as well. They always seem to have the lowest prices, and their customer service is absolutely outstanding. Bought all 3 projectors from them.

Joe Schmoe

Projectorcentral.com gave the Panasonic PT-AE7000U LCD projector really high marks. Some specs:

300,000:1 contrast ratio
2,000 ANSI
4,000-5,000 hrs. lamp life
2.00:1 Intelligent Zoom with Auto Detection (automatically detects 2.35:1 material and fills a screen with that aspect ratio without buying an anamorphic lens)
comes with built-in emitter for 3D (but no glasses)
powered focus, H & V lens shift and V keystone
user can make adjustments to 3D elements like convergence and parallax
480hz LCD panels in the glasses for less crosstalk and a brighter 3D picture

They compared it to the Mitsubishi HC7800D DLP and the Epson 5010 LCD and said the Panasonic has the best black levels in a setting with average illumination, and it does the best 2D-3D conversion. Lowest price I've seen for the Panasonic is $2,975 at PowerSellerNYC. Of course, in the long run it might be cheaper to get a package deal from ProjectorPeople since I'd have to buy a screen, glasses and long HDMI cable. So many choices! So many variables!

Numanoid

I don't know why projector owners always feel the need to hang their projectors. You're right, hanging a projector so that it's 4.5' off the ground would be ridiculous. Fortunately, there's another, far easier and more sensible solution -- setting the projector on a shelf, or table of some kind.

When I lived in an apartment, I had my projector on top of a stereo component cabinet centered just behind my seating area. In my current home, I'm lucky enough to have a deep window at about 4 foot that is directly above and behind my head when sitting in my theater (the couch's back is against the wall under the window). Both setups allowed for perfect projection without having to worry about keystoning and lens shifts. Plus, if I need to adjust the projector's position or lens, or attach/detach some cabling, or clean the filter or lens, I can simply reach up and do it. No getting on a ladder or any of that nonsense. Of course, if your room layout prohibits such a thing, you'd have to go with ceiling-mounted, but I feel like every projector owner thinks it's a requirement of having a projector when there is a far simpler method that is often overlooked.

Spiky

DLP tends towards better sharpness at the pixel level. LCD tends towards a more film-like image. Depends on what you want. I'm not actually a fan of too much sharpness, it can look unnatural. And "film-like" probably just means "not overly sharp". But I've had both, too. They both can be great.

About RBE, it is generally worse on RPTVs than front projectors. I know I found it painful in the first DLP RPTV I saw, I had to leave the room. But I survived a year with a DLP PJ and it was only noticeable with certain scenes, or if I moved my eyes a certain way.

Of course, LCoS is generally said to beat both of those for overall pic quality...that's part of why I broke down and ordered the LG yesterday. I gotta figure out if my current mount can handle 22#.

But also, plan ahead on the positioning. It's certainly possible to do so, although I see comments all the time from people that don't. I find that a little funny, but I do own a high-tech device called a "tape measure", so maybe I'm special. As I mentioned, I have a tight fit. When I planned mine I weighed not just the lens offset and shift, but screen size and position, ceiling height, my height (so I don't hit my head), mount size/design, even speaker size and position. Worked it all out, bought a PJ with no shift at all, hooked it all up according to my measurements, and it worked beautifully.

Or just buy the AE7000 and you'll be fine.

Spiky

Well, that was the point, for purpose of illustration.

Ceiling mount is just a good way to get it out of the way for many, shelf is certainly viable. Since they often have to be upside down when high in the air, some hang them underneath a shelf. I don't have a back wall close by, hanging it from the ceiling is basically my only option.

kvrdave

I think the 7000 is probably one of the best around from everything I have read. But I don't use 3D, so I didn't really consider it. But if I were looking for overall, plus 3D, I doubt there is anything that would make me look away from the 700.

Some times you have to. 30' room with stuff towards the back, couch in the middle, and screen at the end. I could go with a table, but I've got kids, including a 5 year old, so a ceiling mount is really the only way to keep it in one piece.
Good for you. I picked up a ceiling mount from monoprice for around $15 (I love that place) that had great reviews and can handle 50 pounds. My current mount has never made me very happy, though. Figured for $15 I can't go too wrong.

Spiky

I also love Monoprice and snagged one. I've bought several mounts from them over the years. Decided my old mount has a couple weak links suggesting a low weight rating, didn't want to chance a PJ 3x heavier than my current one. I'm going to reposition this PJ, anyway. I should have years ago with my AE900 to get it more out of the way, now I must with the bigger unit.

Next weekend should be most enjoyable.

kvrdave

Mine just showed up. It is HEAVY. I may wait until tomorrow to install it so that I can go up into the attic and see if I can shore up the rafters. I scabbed in a 2x6 between the rafters for the last one, but it still feels heavy for something on a ceiling mount.

Sdallnct

I disagree with importance of lens shift unless you want to put on shelf behind you.

Yes, with no lens shift you have to square both the pj and screen. But in most cases you can move either or both!

For example, when I upgraded to my HD70 I actually moved my screen about 1/2 inch so my pj wouldn't be to close to the ceiling.

But remember with careful planning, measuring and getting "just perfect" only happens once. So spend the weekend getting it right and you are good to go till you replace the projector. I built my mount so it has some pretty fine adjustments and can raise or lower it pretty precisely.


Yes, I'll agree there are some extreme situations. And I certainly won't argue it is "easier" with lens shift. But again, on both my projectors (X1 and than HD70) I just spent the time to get it right and that was that. Never have to do it again. And I certainly would consider my room normal. It does have 8' ceilings and I put in two rows of seating (one on a riser). But it is not overly large or anything.

Sdallnct

Surprised you didn't just build a mount.

Sdallnct

Just how heavy is the thing? And you got the Panny, right? So it has lens shift. No rafter close?

Joe Schmoe

I'm not sure where I'll end up putting the projector. I think I'll have to try it in different places to see what works best as far as image quality and practicality. For instance, I don't know if a ceiling-mounted projector would work because there are 2 ceiling fans in the room. I suspect they'll block the light from the projector unless the image can be directed below their path. Sitting on a high shelf/cabinet/bookcase on the rear wall is a possibility. And, if need be, I could sit it on a coffee table in front of the seating. I want to make sure I have plenty of flexibility. I guess that's why I'm interested in lens shift now.

Sdallnct

Well just don't forget that lens shift is NOT a crutch that can fix anything. You need to decide where you will put the projector. Period. Then you need to compare the projectors you are looking at for their zoom length (they are not the same), throw (no where close to the same from projector to projector), amount of lens shift (yes, different by each maker), brightness for the size screen you want, etc, etc.

There are a lot of calculators and such out there to help you. But you cannot expect any single projector to work in every location of any (your) room. So you need to decide where you want to put it. Sure, hopefully you have a few inches in all directions to work with.

I took my ceiling fan down so that I could ceiling mount my projector. I added a fan to the top of a built in book cased (a long thin one) if I want some air movement in the room. It came with a remote so all good. I than added track lighting to the outside of the room for lighting. This was great as I can aim it on movie posters and such and have them on a dimmer to turn up or down as the situation dictates.

I see I've messed up some of the photos somewhere. But you can get an idea of my set up in the link of my signature.

Spiky

A sheet of metal strong enough to hold this bugger was going to cost over $20. The Monoprice mount cost that much shipped. I actually have never built a PJ mount. I have done many DIY things including parts of speaker mounts, but mounts are so cheap, now.

But this one is almost too big for the PJ. Despite its size, the mounting holes are actually very close together. I was hoping to have a cm of play or so for final adjustment since there is zero horizontal lens shift, but I'm going to have to measure perfectly, instead. Bout half done.