Suggestions/budget advice on possible HD projector?

[mjl5007]

We're currently in the research stage of replacing our main video projector, and I'm hoping to get some input and advice on whether we should seriously consider moving to an HD-capable projector despite having no HD content at the moment, as well as how much we might expect to spend and some specific manufacturer and model suggestions (depending, of course, on the answer to the HD question).

The projector we're replacing is used almost exclusively for showing a DVD recording of the sermon when our pastor isn't in attendance (preaching live at another campus or out of town). The existing projector works just fine, but we've been struggling for way too long with a washed out image on the screen due to insufficient light output from the projector -- we have to deal with outside light coming in through 4-foot-high windows covered with white vertical blinds around the entire perimeter of the room just below the ceiling, as well as keeping the lights in the room on bright enough that the congregation can see to read their bibles and/or take notes.

The existing projector is a Panasonic PT-F100NTU, which is XGA and 3,200 lumens. Screen size is 180" diagonal 4:3 (9' x 12'), throw distance is approximately 33'. Closest viewers are around 14', farthest are approaching 60-65'. I've seen the various formulas for calculating amount of light required... I seem to remember something like 5 times the ambient light per square foot of screen? We do not have a light meter at the moment so I can't quantify exactly how much ambient light we're trying to overcome, but I would guess that we need at least 4,500 lumens, but would much prefer 5,000-6,000 if it's in the budget.

As for the question of whether to stick with XGA or go to HD (either 720p/WXGA or 1080p/WUXGA), I'm torn on that. As I said, we currently do not have any HD material that would benefit from an HD projector, although we are considering replacing our main camera (Sony DSR-PD170) soon as well and may go with an HD camera (something in Sony's HVR- line, or possibly up to an EX1 or EX3). My question is whether having the extra resolution will be worth the cost at the viewing distances I mentioned earlier. There is also the possibility that the new projector could move to our new building in 2-3 years, but we have no idea what the physical parameters of that space will be, so it's hard to predict what sort of screen size, throw distance, or light requirements we'd be working with.

Any and all input is greatly appreciated! Thanks!

[Brad Weber]

Thanks for providing so much information, it really helps!

The issue with HD is often not just the resolution but the 16:9 versus 4:3 format. Since the screens are apparently already existing and you are looking at the possibility of a new venue, I would guess that you'd prefer to stay with the existing screens 9' high by 12' wide screen. If you used a 4:3 format projector you would then have a 9'x12' 4:3 image and a letterboxed 6.75'x12' 16:9 format image. With a native 16:9 format projector you would be able to have a 6.75' high by 12' image for 16:9 format content and 6.75' high by 9' wide pillarboxed image for any 4:3 content.

One related factor is that the rated brightness of a projector is based on using the full image area, thus the rated brightness of a projector does not directly apply when there is any letterboxing or pillarboxing of the image as the unused portions of the image also have to be considered. Basically, when you display anything other than the native format then typically only part of the overall projector brightness is applicable.

On the brightness, the recommended image contrast ratio, the ratio of the peak white level to the full black level at a viewer, has traditionally been 10:1, although the recently developed Standard specifies 7.5:1 for 'passive viewing' and 15:1 for PowerPoint type presentations. The black level is typically determined by the ambient light off the screen, so control of the ambient light levels is often a major component as it is possible to have an uncomfortably bright image that thus sets a maximum peak white level.

From a simple practicality perspective, for the same price you can probably get more in terms of brightness in a 4:3 projector than a 16:9 projector. But you might also want to consider a 16:10 or 1280x800 native projector as that will support letterboxed 1280x720 for 720p HD and slightly better than XGA 1067x800 for 4:3 images.

[mjl5007]

Thanks for the quick response, Brad! Great information about the brightness and contrast ratios, and loss of light output when only a portion of the full image frame is used. All of your comments regarding the change in aspect ratio with HD have flown through my head at one time or another as well, so we're on the same page. And yes, you're correct that we'll keep our existing screen -- it's actually one very tall 12'-wide screen, and we project two images stacked vertically; if you want more details, I have another post from a few weeks ago that describes our setup in more detail: Upgrading a live-to-DVD workflow and SD live projection system to HD

There are actually even more considerations to be taken into account here that I didn't mention in my OP for fear of turning people off with a wall of text (I'm guilty of that more often than I care to admit). For instance, the recorded sermon is distributed via DVD to 3 other campuses each week and they are all using 4:3 screens and projectors as well, so the ramifications for those campuses of a change to 16:9 format need to be considered. At this point I don't believe our budget would allow us to upgrade the projectors at those sites as well, and one of them is in a school auditorium using the school's screen and projector, so upgrading the projector there isn't really an option anyway. On the other hand, having them display the recording as 16:9 letterboxed on their 4:3 screens probably wouldn't be a very big deal.

Another minor concern is that the sermon recording is shown on an LCD TV in the lobby simultaneously along with the projector in the Worship Room, but in split-screen mode where the left half is the sermon recording and the right half is the sermon notes via PowerPoint (also 4:3, and also shown by a second projector in the Worship Room). Putting a 16:9 letterboxed image into a split-screen like that would make the net physical image quite small and squeezed, so we'd obviously want to avoid that. A simple solution would be to just get a second TV and use one for the sermon recording (full-screen 16:9) and another for the sermon notes (4:3 pillarboxed) and do away with the split-screen idea entirely.

The other item I've been pondering over is whether to explore the addition of some sort of hardware scaler/switcher to our setup, rather than sticking with the composite-via-coax that we're currently using. One suggestion I heard is to look into the possibility of feeding SDI/HD-SDI to the projector(s) since it can be run over the existing coax cabling and is cheaper and easier to deal with than HDMI.

I'm hoping to get some of our tech folks together to sit down and hash out all of these issues sometime in the next week or two. However, regardless of whether we choose to go HD/16:9 or stick with SD/4:3, we still need to make sure the projector we end up getting has sufficient light output for our environment. How do you suggest we approach the task of determining exactly how many lumens we need? Should we look into getting a light meter to accurately measure the amount of ambient light we need to overcome, or is there some other process for figuring that out?

Thanks again!