C3X1080: Effects of aging bulb

This is the normal behavior of this type lamp. On my first lamp I got the following ageing data:

Attachment 100078

I retired this lamp to spare status and my second lamp is following the same ageing curve. I've got about 650 lumens at d65 after 875hrs with my second lamp. This is roughly half what it was when new. Not bad at all since it started so bright.

The color characteristics of the lamp change over time especially when you get many hundred hrs on the lamp. After about 700hrs both my lamps started running out of Red and I had to dial the contrast back a notch or two in order to keep d65 in the 90-100 IRE range. This is also normal for this type of lamp.

I think you are just getting used to the image.

Bob

I thought you were being specific to the 1080.

Other than the HT5000 (previously discussed)I will always replace lamps, at least until the technology changes, around the 500hr mark.

How are you switching between bulbs? Swapping out the lamps and firing the pj back up? If so, I would expect to see some differences in the image. After a recalibration with the new lamp, I would expect the differences to be only brightness-related.

I see no reason to do this with a C3X (either the 720 or the 1080) In my case, as I said, I'm getting 650 calibrated lumens after 875hrs. This still produces well over 20 ftL on my 1.3 gain 110" diagonal screen. As long as I keep it calibrated over time, I see no need to replace the lamp. If I put a new lamp in, I'll have to resort to using a ND filter again.

Also, with the Lumagen RadianceXD color management feature, I am able to correct for the over-saturated colors of my C3X 720 to achieve virtually perfect primaries and secondaries x,y and Y.

I'm going to wait until the lamp blows, then put my backup back in play.

There's nothing wrong with replacing the lamp at 500hrs, but I'm too frugal to do that.

Bob

New lamp and recal.

This data shows 50% light output at 550 hours is that about right.

Art

I didn't measure lumens when the lamp was new, so you can't really tell when it hit 50%. My educated guess is that it was somewhat lower hours than that - probably 300-400hrs.

Bob

Yes, I have a C3X 720. I hadn't realized the C3X 1080 was so much lower in lumens than the 720 unit. I knew the larger panels cost some light output, but it appears that it is 3-400 lumens less than the 720 version. I did a little web searching and the only real data on light output from the C3X 1080 I could find was from Coldmachine. He said the 1080 is around 1100 lumens at d65. The C3X 720 is around 1400-1500 at d65 when new. Both are capable of much more is you're willing to settle for a higher color temp.

I believe the lamp ageing would be similar between the two units, declining rapidly in the first two or three hundred hours before leveling off to around 40% until it blows.

When I say calibration I mean full color calibration, not just brightness and contrast. I'm a nut in that I calibrate mine every 100 hrs or so. Keeps me in practice.

Do you leave your ISCO in place when watching 16:9 materiel? My screen is a little smaller (127x54) than yours and I remove my stretch lens when watching 16:9 due to its bad affect on ansi contrast.

Bob

Yes there is a big difference unfortunately. You can get around 1350 on the 1080 if you trash the temp. I never would so its an 1100 lumen machine.

The WORST C3X ive seen was 1300 at D65, 1400+ is more typical.

I remember Jason saying that his C3X installs were hitting 1400ish.

If only they'd done away with that case for the 1080.

So are you satisfied with the current lumens on the C3X. I was told the loss of lumens was help create a richer black level. I have a 110 screen would that still be plenty bright. Thanks greg

The C3X1080 has plenty lumens for most apps and a 110 screen wont tax it in any way. You couldn't use it on max power.

Are you talking 16:9 or 2:35 with ISCOIII and is it 110" diagonal or 110" wide?

I am about to pull the trigger on my screen, as my projector will be here shortly and I wanted to check it all out and be careful before I ordered the 2:35 screen re size (with an ISCOIII ceiling mounted). This thread has reiterated the concern. I like going big but I want to ensure that as the bulb ages that I have adequate light output and the DLP "pop" to the picture. I am willing to not go as big as say The Bland so that I get that "pop" to the picture. Screen gain will be 1.3. Dark, light controlled room. Assume projector will be mounted towards rear of throw range, T2 lens. What width 2:35 screen do you recommend, Coldmachine, for this purpose? What will be the expected fl of the screen size that you recommend?




Thanks.

At 110 wide 16:9 and 1.3 gain you will start at 30fl.

I have an 8ft wide 1.3 that unmasks to 10.5ft and need to dim it. It was 40fl and 30fl when unmasked.

Personally i would put the limit at 12ft wide for this machine, and consider my 10.5 to be perfect. That will give 23fl or 21fl if using a typical AT screen

I firmly favor Stewart screen but also look at SMX. DaLite are also good and cost a lot less. I had one of their masking screens (Multi Mask Imager) and it was flawless.

I hope you don't mind if I give you my opinion.
I would plan your screen size to give you 20ftL after your lamp has reached 50% reduction. If you start with 1100 lumens and plan for 550, then I would recommend a 110" diagonal screen in 1.78 aspect ratio, or 127x54 in 2.35 ratio. This would provide you with (550/36)x1.3= 19.9 or approx 20 ftL at half brightness with a 1.3 gain screen.

You might prefer using a ND filter when new to reduce ftL, but at least you have that option.

That's my opinion.

Bob

Good points. The latest bulb data, however does not support a 50% drop.

HT5000's are hitting 25-30%loss and the 1080 is around 35% loss.

I welcome all opinions of Sim2 experienced users.

My screen will be solid, not AT, and will be Stewart Studiotek 1.3 gain.

Does this change your opinions at all?

Thanks.

I assumed that was the screen you were getting (1.3 gain) so my opinion remains the same. If coldmachine's info on lamp ageing for the C3X1080 is true (and I have no reason to doubt it), you could go a little larger than 110" diag (1.78 aspect) of you wanted to.

Bob

I finally got mine installed yesterday and as everyone says there is that wow factor that is indescribeable until one experiences it. Mine is a humble (according to Steve who now might be going smaller) Stewart CineV 130 2.35 and it is plenty of screen for me. Today ISF calibration on the projector and final calibration on the Isco lll and Cineslide

COOL!!! But you my good friend ain't humble. HA!!!!

Congrats.

The concern is whether the WOW factor will continue after the bulb fully burns-in. Thats what I want to base my 2.35 1.3 gain solid non AT screen with ISCOIII width on.

OB, I just hope your mounting distance works ok with the ISCOIII in consideration of Healthnut's reporting of his very poor experience in this regard with the T1 lens and a short throw ratio of 1.5.

Steve I learned my humility from you

I will let you know this afternoon about the Isco and any problems. It is mounted the way GetGray recommended with the extra hardware he supplied and it is rock solid. Preliminary viewing yesterday seemed OK. I would anticipate the loss of "wow" factor more quickly with the largest of screens such as the one you are buying than with mine which IMO is just perfect for my needs.

that is where mine is for now and even with the iris closed it is very bright with great contrast

The 1080 figures need to mature a bit will more units, but indications are that they are close.The HT5000's are good, with some even better.

Steve. I am using a 140" wide 2.35:1 ST 130. I have only 95 hours on the bulb, but the picture is fantastic. I use the low lamp setiing with the Iris open. A smaller screen will give you a brighter picture, but at the expense of the "wow factor" of the larger screen. I am planning to increase the wattage as the bulb ages. Just put the darn thing up already and enjoy it!

J

It started with 20fL at 16:9 and about 15-16fL at 2.35:1.