Sim2 Lumis Owners Thread - Page 6

Originally Posted by gamelover360

I am actually thinking of going 100 inch diagnol since the Lumis T1 offers a short throw of 1.3. That may allow me to deal with room contstraints and still throw a 100 inch diagnol image.

I don't know the furmula you are using but if I assume that the numerator is the light output and the denominator being the square footage of the screen......then....

At 92 inch : 1800\\25= 72 lumens

At 100 inch: 1800\\29.5 = 61 lumens


Can't I close the iris, or adjust something to get less light output? I don't want to watch the sun!

Originally Posted by gamelover360

Could someone please comment on any differences between the PQ on the Lumis and a C3x 1080......black levels, shadow details, motion, depth & dimensionality, etc.

I will only be getting a 92 inch screen (complete light control) due to viewing distance restrictions (10 feet away feet away), so any thoughts on how PQ may compare in that environment is appreciated as well (T1 lens....about middle of the throw range, iris closed down pretty far due to the high lumen output at this distance, low lamp, etc.)

Originally Posted by Ian_Currie

In my opinion, the differences aren't huge: Lumis is better in low lit scenes (because of the dynamic iris) and it's also much brighter, which it sounds like you don't need for a screen that size. Also, with that size screen there are other projectors that are valid alternatives.

Originally Posted by Ian_Currie

In my opinion, the differences aren't huge: Lumis is better in low lit scenes (because of the dynamic iris) and it's also much brighter

Originally Posted by gamelover360

I am actually thinking of going 100 inch diagnol since the Lumis T1 offers a short throw of 1.3. That may allow me to deal with room contstraints and still throw a 100 inch diagnol image.

I don't know the furmula you are using but if I assume that the numerator is the light output and the denominator being the square footage of the screen......then....

At 92 inch : 1800\\25= 72 lumens

At 100 inch: 1800\\29.5 = 61 lumens


Can't I close the iris, or adjust something to get less light output? I don't want to watch the sun!

Originally Posted by GetGray

Anyone tried a high end ND filter on one of these yet? Would *really* love to see soem measurments on it's effects.

Originally Posted by coldmachine

Have you actually own, or have you spent any significant time with, a Lumis? The low light performance is NOT simply due to the DI....Its due to the whole combination of relevant techniques. The lamp modulation is a major factor here too. The Lumis is also significantly better in brighter scenes too.

Having spent some time with a Lumis and a C3X1080 on the same screen, I would have to say the difference is significant. Those who have done the same agree.

1.The brightness difference is major.

2.The CR difference is huge.

3.The black level difference is night and day.

4.The ANSI CR is certainly noticeable.

5.The connectivity is massively better (if you need it).

6.The install flexibility is superior.

Mine was sharper, but that may simply be luck of the draw.

The C3X1080 produces a fine image indeed. The Lumis I used was simply the best image I have ever seen.

Hope this helps.

Originally Posted by Ian_Currie

Hey, I'm not trying to say the Lumis isn't a good projector - I think it's the best you can probably get for a *huge* image; my earlier post was directed at a screen size of 92"; in my humble opinion you can do better at this size.

Originally Posted by odyssey

I don't have measurements, but I think that it would be about a 10% loss of ANSI CR with a very high quality ND filter.

The best solution is to use the excess light output to improve the image. Using a 0.5 gain screen instead of a 1.0 gain can increase the ANSI CR from the screen by 50%.

Originally Posted by coldmachine

I think it was Odyssey who mentioned that Schneider do a top notch one.

I would also be interested to see some results.

Originally Posted by GetGray

Sorry, I gave you the shorthand version...

The formula is (Lumens / Screen Area ft^2) * Screen Gain = FtL

You can find FtL recommendations in a fairly wide range. I thing SMTPE is 16FtL but that might be without film. A lot of people looking at these PJ's, myself included like a much brighter image. Once I had bright I could never go back to dim(mer). Personally I like about 25FtL, maybe more.

So as others mentioned, depending on your preferences, you may find the Lumis too bright. As CM pointed out, you can get a lower gain screen which will help some as the formula shows. I'm leery of the ND filter, too.

HTH, Scott

Originally Posted by Ian_Currie

I don't own a Lumis, but I spent some time with one recently.

1. Agreed.

2. Disagree. I was disapointed to find the CR wasn't much improved over the C3X1080. In fact, isn't the native CR pretty similar? Everyone is touting the high CR when you measure a checkerboard screen, but that's with DB engaged. When it's not engaged - and remember, it's 'dynamic' the CR looks to be the same as my C3X1080. High contrast isn't just desired when black is on screen. I used a lot of professional test videos that required high contrast to give the picture any sense of depth but did not necessarily involve a lot of black (e.g. close ups of fruit or wine glasses etc) and to my eyes, I was simply seeing native contrast. I've seen these same images many times on both my projector and a higher contrast projector and know the difference.

Now, if resolving the image requires a lot of black (for edges, bumpy textures etc) and there's enough black on screen for DB to be engaged, the Lumis looks smashing. So what I'm trying to point out here is that the Lumis doesn't seem to perform like a projector with high native CR.

3. From what I saw it was definitely improved and I want one myself for that reason.

4. Agreed - at least with DB engaged.

5. Agreed.

6. You got me on this one, but I'll take your word for it.


Hey, I'm not trying to say the Lumis isn't a good projector - I think it's the best you can probably get for a *huge* image; my earlier post was directed at a screen size of 92"; in my humble opinion you can do better at this size.

Originally Posted by Art Sonneborn

This is literally the first time since I've been in this hobby and have seen too much light as a topic. Pretty cool really.

Art

Originally Posted by gamelover360

PFL = (Projector Lumens / Screen Area in Sq.Ft.) X Screen Gain

That is what I found online....so I would be at anywhere from 30-35 ftl with a 0.5 gain screen. Is that way too high to be comfortably viewable? I do not feel like the filter route would be something I would want to do.

Originally Posted by GetGray

Well, Schneider, per se dosen't, I don't think. But, Schenider bought B+W who makes high end filters. I've used them in the past in photography work and they are nice. But I don't think there is anything particularly different from them and other high end filters (i.e. Tiffen ultra, etc.). Edmunds Optics has some high end ND filters, but none of these are designed for this task I don't think.

Anyway, would be good to know how much effect these would have.

Originally Posted by Ian_Currie

2. Disagree. I was disapointed to find the CR wasn't much improved over the C3X1080. In fact, isn't the native CR pretty similar? Everyone is touting the high CR when you measure a checkerboard screen, but that's with DB engaged. When it's not engaged - and remember, it's 'dynamic' the CR looks to be the same as my C3X1080.

Originally Posted by Ian_Currie

I used a lot of professional test videos that required high contrast to give the picture any sense of depth but did not necessarily involve a lot of black (e.g. close ups of fruit or wine glasses etc) and to my eyes, I was simply seeing native contrast. I've seen these same images many times on both my projector and a higher contrast projector and know the difference.

Originally Posted by millerwill

I don't know how the Lumis behaves in this regard, but it's common for pj's to loose half their brightness within ~500 Hrs on the lamp. So keep this in mind, as it would bring your 30 ftL down to 15.

Originally Posted by odyssey

It's actually Century Optics, acquired by Schneider. This is a product line for the movie and video industries.

Originally Posted by coldmachine

Bill,

The Lumis wont drop anywhere near half if it behaves like the others.

SIMs drop around 25-30%. Some are actually under 20%.

The power management is a bit more sophisticated than other domestic units, hence the lamp lives normally being double.

Originally Posted by sierraalphahotel

Like gamelover360 I will be limited to a similarly small screen in my room. I too would prefer the excess lumens of the Lumis. I had been recommended a GrayHawk RS G3 material and while I'm far from an expert; I'm sure the image would look satisfactory.

Sean

Originally Posted by coldmachine

Do you have any sort of rough idea of the performance of these filters?

Originally Posted by brain sturgeon


I recall that Alan was using an ND 0.9 with his-- maybe he could chime in with some measurements...

Originally Posted by millerwill

Tx, CM; didn't know that (as well as many other things).

Originally Posted by Alan Gouger

I went to a larger screen size (1 foot wider) and using a negative Grey screen from Carada. I have over 100 hours and I am showing no light loss as of yet.
Ive never encountered this before. Ash or anyone else Id be curious what you find after you put some hours on your Lumis. I am sure I will see a drop sooner or later.