Some of us since to think otherwise!! If my screen can look even close to that of "elken2004" with just a 150W lamp, I'd be mighty happy. Some of us love efficiency.

Hey elk, I must thank you for the good research you've done with that lamp. I'm looking forward to try the same. Problem is, nobody seems to carry it here in the "states," nor do I know what type of ballats to use. Can you enlighten me with some detail about your set up please??

This is another very important thing about this design. You can eliminate a heat shield and I believe that it's safer to run. You can probably use smaller fans and also because it doesn't double as a heater it can be used in a smaller space without gasping for oxygen. I noted that some larger watt models had to be vented outside because of the heat. More heat might be ok in the cold Canadian winters but I don't think it's the most efficient way to produce it.

So many new (to me) things have been tried and tested by elken that deserve recognition. Two different 150 watt ceramic bulbs, tests with the standard lens and a mod to the triplet lens, homemade fs mirrors which seem to outperform store bought fs models, a few different fresnels, software adjustments still not fully determined etc... I would have to go back and reread the whole thread to find all the good stuff. That's why a recap would be so good in helping to eliminate some of the older stuff that you've discarded elken.

I've been keeping my eye on various designs to minimise the box size and that is why although in time a completed pj would be nice to see, the box of this pj is the least of my interests right now. It's more about how the various components go together to make it work. If later, I could incorporate this into LL folded 17" design that would suit me fine.

17" monitors are reasonably priced in my area right now. A new one sells for about $170 to $185 can. I could also go for a 19" with a lowest price of about $249 plus taxes. But that is putting the cart before the horse. I'm still fuzzy brain around this stuff and I need much greater detail about this design and the availability of suitable pj parts in my city (Ottawa Ontario Canada).

Another thing I've seen thrown around is that commercial projectors are rated at very high lumens.

I don't think it's improper to compare elken's findings to moderately priced commercial units.

Please hear me out.

Many svga and xga office projectors use 135, 170 and up to 200 watt bulbs. They rate their projectors on the highest light producing spectrum. So it may be rated 1000 to 2000 lumens but that is not it's normal operating brightness. A number of professional reviewers have found that those PJ's rarely meet the stated lumens and often miss by 20% to 30%. After about 100 hours of operation there is also a significant drop-off due to the burn in of the bulb.

When reading text, charts etc..., you may want the full brightness because business projectors are used in boardrooms where it is often impossible to dim them properly but you wouldn't really watch video that way. I don't know if elken has pulled back on the lcd brightness control but if he did then he too could do like the commercial units and open the gate to the max.

When you measure one of those commercial units to compare it has to be done when it is properly set for watching video. This is the greatest surprise. I checked around and was shocked by the actual total lumens (lux, foot candles whatever measure you prefer) that are available when properly adjusted for video. You can see for yourself using projector calculators like those available on projectorcentral.com (not affiliated with this site but they have an online calc that adjusts by model, use, size of projection and distance.) Most models become dark room use only when used in video mode and projected at the size we are discussing here. If you test it out you will see that in video mode, most can't handle ambiant light unless the projected image is about 60" or less (1.5 metre) diag.

I don't have or need personal measurements. I let their calculator do the figuring for me. I wanted to buy a commercial unit but couldn't understand the brightness dropoff when a unit was adjusted for video. Some higher (3500 to 4500) lumen and wattage models fare a bit better in ambiant light but the cost is about 3 times higher and the bulbs are 2 to 3 times more expensive. Even at those higher ratings, they are still showing that when operating those in ambiant light in video mode the suggested image size is only a bit larger (maybe 72" diag ) but look at the much greater operating cost for that gain.

This is why I say that I believe elken's design compares well with any of the $1000 to $1800 can. xga models but at a lower cost with cheaper bulb replacement and I'll bet it even exceeds some of the lower end models.

If you are talking about using one in an auditorium then I would probably agree, look elsewhere.

Time will tell if there is another ceramic bulb rated at 200 or 250 that does a better job. Who knows elken may try that himself later on, but right now this seems to be the best bang for the buck when it comes to home video in a home theatre setting. It just needs tweaking to obtain the maximum settings and then a parts list so we can make our own pj.

Nervous times again

stepped upto a 19" panel. currently undergoing A/G removal,, looks like it will be a half hour breeze, absolutely no issues with strip,, and perfect config for PJ usage

single row FFC's, and these are bonded heavily within glass and epoxy,, only prob is if you tear them, really good single enclosed power module and smarts unit, just lock and load into PJ,, LVDS2 connector brilliant... I am in love again...

Resolution?

1440

DAZZZ that eye still looks pretty bad....

have you chewcked out how it scales 720p? should have black bars at top and bottom if it scales it correctly...what about 4:3? pillar boxed or stretched? what monitor?

elken did you ever try a 600> fresnel in your setup ?
I got my parts, 330/630 fresnels with a 22" triplet (stilllll looking for an lcd) ... I am curious how the image is going to be with the 150 powerball ...

also you mentioned about a zoom lens contraption, with an additonal mirror zoom in can be achived but can you also zoom out (make the image smaller) ...

Not trying to support or refute those claims...just provide additional information:

most of those commercial PJ's put out about 300-400 lumens in their best video optimized modes - as measured by the reviewers. That won't tolerate any ambient light. Some of the newest models can greatly exceed that and still project excellent video. Hence they are touted as better able to handle real-world environments such as a Sunday football party. The extra brightness also helps combat any loss in lamp efficacy over time - which are said to be much better now as well - don't die off as quickly.

Someone can get there with a low-lumen DIY PJ (100-150 lumens) and a high-gain screen - if you can live with the limited viewing angle (some can...some can't).

There's two kinds of comparisons people can make:

1. Subjective - in which anyone can say anything they want and probably should be allowed to, if they truly believe it - without offending anyone of course in the process.

2. Objective - in which measurements are the criteria, such as lumens or contrast or color fidelity, etc.

We seem to do well when we rely on the objective comparisons. The subjective ones can really cause a lot of debate and heated discussions. All of us must be careful dipping into those waters....

But if someone is getting great results - like elken, they should be allowed to say how much they like them...

Sometimes however, the only way to verify those claims is to either try to duplicate them, or ask for objective measurements to support them. But we must be careful when doing so as to not make the person think we are calling them dishonest, etc...

dajyn are you in Politics?

Learn how to adjust the shutter speed of your camera and it very well can.

Yeah , i have a giant suede wrap around L couch. I would rather not have to explain how all but 3 seats are useless.

Edit: Okay, I'll remove the sarcasm/joking/kidding and just simply and plainly state my opinion of some comments.



It truly does not matter why a high-gain screen wouldn't work for you. That doesn't add anything to the CDM150 experimentation. The size, shape, or material of your couch has no bearing here.



Accusing Elken of publishing misleading photos that don't represent his real experience is also out of line. If for no other reason than that it makes no sense for him to put this much time, money and effort into duping everyone. Why would someone do that? You don't have to believe his results. At least he is contributing something.

From another thread:



I'm all for diversity and tolerance, but pretty soon you're going to "tolerate" yourself into a forum full of these guys.

we can all get a little sarcastic at times...(except perhaps Dazzla )

or a lot...in some cases.

But I think Mikelish was just trying to explain (in a negative tone perhaps) why a high-gain screen wouldn't work for him. It doesn't work for me either, because of my seating arrangements and personal preferences.

But I believe that high-gain screens can work for a lot of people...and may be one of the only ways to overcome the illumination problems of many DIY PJ's.

A little bit of sarcasm can probably be tolerated in these forums. But personal attacks should never be. I don't know all that's been said here - thankfully it was edited/deleted out before many of us got a chance to read it all.

But I do sense this is getting personal for some people. That's why we should all try to moderate our own comments (lest the moderators will do it for us ).

I think it's good and interesting to have opinions - it would be pretty boring if we all thought the same. But let's try to leave an opening for someone else's perspectives or experiences. Except for a few basic laws of physics, there are no absolutes in this universe. And even those laws might be changing as our understanding of them grows...

No, I'm not a politician. Do I sound like one? Am I full of a lot of hot air - or tend to say the same thing three different ways?

That I may do sometimes. But we all think and view the world differently - and sometimes respond to different messages. Let's respect and value our differences (now I really am sounding like a politician ).

I've found that the most beautiful forest is also the most diverse...

I believe there's a lesson there about life...and people.

I agree, unless one of the trees keeps bursting into "flames." Maybe the forest could do without that tree.

we'll just keep pouring water on that tree...

eventually it will become so soggy - it will be quite pliable and flexible.


we all can use a little dousing from time to time...

and no one should get ostracized because of it. I know I wouldn't want to be.

@dajyn

Getting past my use of many words........

My point is that even commercial pj's with high lumen ratings are said to work best in low light conditions or near darkness when viewing video.

When asked about the prebuilt pj being sold by LL, Brainchild said this:



here is the whole text in case someone wants more info:

Brains comments

No one can argue about which model has more overall lumens but in a home theatre situation where screen size may not often exceed much over 100" diagonal then the question could be asked, is it really of much benefit to go with a higher rated bulb?

Let's say that for argument sake the answer is yes, then for a similar ceramic bulb where do the benefits stop: 175 watts? 200 watts? 250 watts? And remember you'll still have to dim the lights to get the blacks in your picture. I'm sure someday soon someone will test this out also. It's probably a natural progression of things to answer nagging doubts. I suspect that the gains if any will not be dramatic for a normal home theatre setting and screen size.

Not quite sure what you are asking here, but too answer if more brightness affects daylight watching, the answer is 100% yes. Ogo and i am sure others will back me up on this. At 400 lux, (not lumens, but actual lux) on the screen, average, you can watch comfortably during daytime at 100 lux in the room without any projection. 100 lux is about what you would expect with your shades open, and no sun, or sun and white shades turned to shut. If you have a 100 lumen projector, you will not see anything, since you are at 100 lux. At 400 lux, you are still 300 lux above and beyond that. You are still 200 lux above a projector like what we have been talking about. I'm kinda lost on what Brain said. The black pictures are able to project to the wall? Even though they are grayed somewhat, you still can see when the film goes to a dark scene. As you ask about watts, remember, many theatres are at something like 4000 watts or something crazy like that. AV is gonna test a 2000w. I think for my goals, 1200w small arc, double ended does the job. In my case, heat is not an issue, but as for some, it may be. My box is very large, and a designed airflow that keeps it cool. The air coming out of my projector is only luke warm.

gumshoe - I understand your point. My PJ puts out 150 lumens at most and even in a completely dark room with dark walls I still feel it's not bright enough for my tastes projecting on a smallish 1.0 gain screen.

That's one of those purely subjective opinions. Each person needs to decide what is good enough for them...or not.

I feel that if I had another 150 lumens, then I would likely be satisfied - while watching high quality video - DVD movies, etc. - in a dark room.

But someone else may not need that additional brightness. However, many people are now using high-gain screens, like Elken is I believe, and this effectively bumps their perceived lumens up near the 300 range or more - if they are positioned to receive maximum benefit from it.

And so the 300-400 lumens number may not be quite an absolute (there are none ). But it could be very close to a common denominator of some kind. Until you get there, you might not be satisfied. And even then, there will always be some who want even more....Lumahn

I think I measured about 100 lux or so in the center of my screen and 60's in the "squares" surrounding it.

This averages out to about 75 lux, which is less than a movie theater. They recommend 16 lumens/sq ft. or about 170 lux. (I've read that most theaters probably only achieve about 100 lux on average.)

If I had that much (170 lux) I would be up in the 300 lumen range and matching a good movie theater - in a dark room.

I'd love to have even more power, when I needed it...for the reasons that mideo mentions - combating ambient light.

that 100 lux has been questioned by some here. I don't have an opinion on it. My personal guess, is maybe it was the old days theatres at 100 lux, and more now, but who knows. I think we are all too chicken to go up and test it.

give us teh lumahn ffs

next week I'll get my powerball's and MichaelJ's luxie-meter so ph34r

ummm just to clear up a point

my screen is not high gain,, it used to be,, be in house move got scuffed,, so it is a plain straight white screen now,,

Yes sir, I don't understand why we have to be negative toward a member just because he/her is stating something that most people would find hard to belive. I'm a newbie here and I surely appreciate every little bit of detail and info that someone can post. I make choose not to believe it, but this does not give me the right to hammer that person or be that sarcastic in my responses. I want to learn from the members here, not fight with them.

hey whoa guys,,, tis ok,,, I had a little spat der other night,,,

miedo's is entitled to his opinion... as is everyone,,,

so lets nots let this get out of hand again..

different strokes different folks,,, to be or not to be.. that is but the question..

in this day and age photo's now can lie,, it all depends on how they are delivered.. and the perspective of understanding of the viewer as to what is really is what. etc etc ect..

well... I did it... 150W ceramic (Philips CDM150/T6/942)...

In brief:
Small arc (~9mm) and arc chamber (~20mm) are clearly visible in the triplet upon startup... this is much different from previous lamps which "just fit" into the triplet. The entire arc chamber can be clearly seen from all corners of the screen. All of this leads to improved image clarity and improved contrast. Brightness is certainly lacking, but stands up well to some ambient light from lights in the back of the room, but not nearly as well as the higher brightness from the 400W HQI-TS. My panel is currently unadjusted with RGB set to 255/255/255 on my WUX GA2 controller. The image as you might imagine is certainly on the "warm" side... my thinking at the moment is that red might actually need to be knocked down some, but it's a bit premature to say as the lamp has already changed color slightly in the two hours it's been on. Something unique hit me while using this PJ with my son tonight. He typically runs around in front of the screen and previously with other lamps (i'll call them the long arc lamps... HQI, T15 PS, PlusRite T15, etc..) his shadow would only be in focus when he got close to the screen and holding a finger in front of the projection lens would have almost no effect on the brightness... that has all changed with the new short arc lamp... even when halfway or more from the screen (to the PJ), his shadow is clearly visible (although not in sharp focus) and holding a single finger in front of the projection lens will severly diminish the brightness of the projection... there is a reason why commercial units try and get arcs as small as possible...

My setup at the moment is the CMD150/T6/942 lamp, pro reflector, 4.5x6.5" condenser (ss), 3D lens 330 (0.2 pitch) / LL 650 Pro (0.5 pitch) fresnels (unsplit), Sharp WUX (...W12), and a temporarily modified pro triplet (using a 4.125" o-ring from the local hardware store).

More later.
cheers,
gs

GS - can you elaborate on your thoughts regarding the advantages of a small arc size and your son's shadow, etc?...

@miedosoracing
I appreciate and understand your explanation of your normal lux readings and lighting conditions.

I avoided discussing lux, lumens and foot candles etc.. because we have no real measurements of such on this setup. The posted pictures speak for themselves. I used smaller increment bulb watts as an example (175, 200, 250) if such were available because looking at elken's results I find it hard to believe that any adjustment (if I felt I needed one) would ever be in the 1200 to 2000 watt bulb category. I've said before, I'm new here and I have no direct experience on the subject but from reading many posts about lamps those would never have the small arc that the 150 watt bulb has and which I think is one important part of the efficiency equation. Based on elken's pics, the fs homemade mirror seems to be another positive variable. The precondenser, the panel, fresnel composition etc... all have some part to play also but those are not specifically clear to me so I'm interested in getting more info on those.

I do have another point about lamps:

I found two terms when referring to lamp measurement . I'm not sure if outside links are permitted so I won't point to the site but it's simply table of common light terms.
First they speak of "lumens" in terms of the whole sphere of the bulb and then "End lumens" more as a point of light source (without reflection). When lamps are classified they always use the greater lumen value for the whole light sphere but we only use and need the "End Lumens". I know this has been said before using different terms but I believe elken's ceramic bulb has a better "end lumen" to "overall lumen" ratio which is why it is more efficient at using the light. That won't make it as bright or brighter than a 400 watt bulb but maybe the difference is not as pronounced because of this efficiency.

This term "end lumens" is interesting too because it seems to mean direct unreflected light. Those of you with more experience could answer this but is all light going into the precondenser or the first Fresnel useful for projecting on to the lcd? I just wonder if the reflectors used with wide arc bulbs only pick up stray light that does nothing to enhance the image but increases the lux readings at the screen.

[/quote]
nice pic ogo but where is your plog or build or anything on how you got that pic or a pic of your pj or something cuz im not getting it, as in how did you do that.?????????????????????????????????????????
:angry:

I don't have a PLOG here cause I come from a french forum. My (in french) PLOG is HERE. You will also find here many other shots like this one. Those shots are 2.3m base (see the CD on top right), on a dalite 2.8 gain screen, HQI 400W

I'll start a new thread about tweaking, etc, as soon as I will have finished my current mods on the proj ...

Same findings as my tests on the red being a bit strong but at least it is a "true" (ie not orange) red. Don't you find the blue is lacking ?

If watching during the day is your thing..you could always try building yourself an RPTV.

In this space shortly,, very large projection,, in fact whole screen filled,,

just to put to bed about size of image with a 150 watt @ 1440 x 900 res

here..

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more

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only prob was the person using cam,, blurred them also full auto cam

plus optics are not at opt either, just as is..

by my light measurements,, in past I am about 20% down on lumies to screen.. minor issue however

ummm 96 inch diagonal or 80 inch wide

ok,, here's the scoop

I dont know how many people have worked with several different panels

but the fact is is that each one is quite unique in its requirements

every time I play with new one, the old formuals dont apply

simple fact,, so hence why we all seem to differ in what is what etc

I am now going thru a learning curve yet again, with a new panel,,

like quicksand tis it

and another thing,, as it stands,, I dont advise anyone get a 19" widescreen due to the format, issues etc.. unless someone can tell me some secrets

hmmm... what do you mean exactly ? what issues ? ... you're one of the first people to use a 19" WS, it's been my thoughts that trying to get a good "clean" cone of light to cover the 19" is just that much more difficult than a 17" ? is this true (or not) ?

yup. same here. 3 total, what I would call, "very different" panels... soon to be a fourth...(7" 16:9, low res) ... it was my opinion at one time that the electronics and the way they are calibrated had much to do with the differences (and maybe that still is) however, when you started going into examination of the color filters of the LCD's it occurred to me that this may also be a source of differences... and of course the polarizers and "other layers" used... so many variables...

gs

Thank you

elken have you ever measured the transmissivieness of your panels? I would guess the new panel is less transmissive than the last one...

not sure about the blue... i guess I will only know that after I make some adjustments... i'm only doing these by eye, so whatever the results, it will be open to interpretation. A general observation about softwares adjustments.... I use powerstrip as it gives an opporunity to make and save different color profiles... one simple adjustment is adjusting the color temp. (default is 6500K). When using the HQI-TS I would adjust this downward (lower color temp) to help remove blue and add some "warmness" to the image... now with the CDM-T I need to adjust this upwards (increase color temp) to remove red and "cool" the image somewhat. Both of these observations are just fooling around, and with the controller RGB set to 255/255/255. Perhaps I can do the "white screen" test as you outlined and post the results ?

that is one of the nicest photos i've seen of a projection. I don't speak or read french, but i'll give google a shot at translation and see what I can get out of it. Yes, a new thread about how to tweek would be great if it helps get images like you have !

not quite sure what to make of it. I believe because the arc image in the triplet is much smaller, as far as getting light to the screen, we are using much less of the triplet... the light is much more "focused"... less stray light coming from unwanted angles... I believe it all comes back to the arc... i've got something to test with the HQI to see if I can get similar results as with the HQI... all a test about arc size, but basically "stopping down" the arc size on an HQI (or other similar lamp with ~30mm arc or so)...

gs

Now that is an impressive set of pics. Very nice image with a slew of in-room lighting. Hmmm 150W bulbs are looking nicer and nicer......

Why does this happen to me......now I want to get a new bulb!!!

sorry what i meant about 20% down was due to changing some optics, still have A/G on,, was more tangled up with tryingto get panel to behave correctly with drivers and aspect ratios etc..

plus getting used to what waht is what with rgb etc etc

every panel behaves slightly different, but that can translate to big diff in reaction on screen

like learning to drive all over agian heheheh

its funny how you get used to having no A/G and how good it is without it,, thats where a fair percentage of my light loss is,,,

where i got say 38uW centre in past 17" panel this with a/g is about 23uW

and yet it gave the images earlier tonight..

I believe 100% correct. I am the first person who said that here (page 21), that the arc is the reason. That is exactly why the professional commercial units turn their bulbs so the arc is vertical from the lcd. That makes the arc 1mm or something. We are facing the bulb horizontally, so the arc is the length of the arc. So that is why I think a 575w or 1200w could be as sharp, if the arc is turned or even a single ended bulb is used.

I know we're starting to get away from the CDM150 purpose here, but since it was brought up...

I've often thought about this as well. The longer the arc, the harder it is to get a sharp image, would you agree that is accurate?

If so, isn't there a relatively simple way, using a concave lens of some kind I presume, to sort of "focus down" a long arc, but only on its long axis, and yet retain most of the lumens? I mean, if we use a plano convex precondenser lens to enlarge the arc chamber of the CDM150's, could we use a concave lens to focus a 30mm arc down to 5mm?

I'm sure this has been discussed before, being that LL has been around for years.

I am sure others have already gone 19" wide...

here are two shot tonight.. did an oops with flash

full auto on cam again too..


grr hate post double

anyhow,,, I may grow to like this panel,,,, its just new,,, just have to learn its personality

I am sure others have already gone 19" wide...

here are two shot tonight.. did an oops with flash

full auto on cam again too..