I am sure this is different depending on the projector (or is it?), but what is typical of UHP bulbs in reguards to brightness loss? Is it say 10% every 100 hours and it plateaus once it gets to a 50% loss approx and then stays at this point for the remainder of the projector lamp life?

I am sure this is different depending on the projector (or is it?), but what is typical of UHP bulbs in reguards to brightness loss? Is it say 10% every 100 hours and it plateaus once it gets to a 50% loss approx and then stays at this point for the remainder of the projector lamp life?


Based on all of my reading around here, there is a very sharp drop-off in the first 200 hours of bulb use. This initial plummet will be somewhere between 30% and 50% of its brightness. Most of the actual measurements I've seen posted have been closer to 30% than 50%.

After the initial burn, it continues to drop at a much lower rate until the end of the bulb's life.

danielo and krasmuzic have posted some good data in this thread:

http://www.avsforum.com/avs-vb/showthread.php?t=641904&page=10&pp=30

Here is a graph of danielo's data with a logarithmic trend line

http://gallery.avsforum.com/data/501/H79Lamp.gif

The measurment data in the above graph seems to coincide closely to my practical experience with the 2 bulbs I have gone through with my H77.

Thanks for the info guys. I was expecting it to be worse for some reason. According to the chart, by the time you get to about 500 hours, you have lost approx 1/3 of your lamp light which I figured it would have lost 50% by this point.

But that Optoma projector seemed to be particularly bad at burning out bulbs. Some pretty long threads on the issue. I highly doubt the H7X series can be used as any gauge for projectors in general.

But that Optoma projector seemed to be particularly bad at burning out bulbs. Some pretty long threads on the issue. I highly doubt the H7X series can be used as any gauge for projectors in general.

I actually thought about that when I saw the graph......hmmmm

Maybe a typical UHP bulb projector would be a little slower?

I actually thought about that when I saw the graph......hmmmm

Maybe a typical UHP bulb projector would be a little slower?

Tryg had a very nice thread dealing with the Ruby and its various brightnesses before and after bulb break-in at various throws. The thread must have been archived because my link to it is broken now. You might be able to find it though.

I believe the assumption regarding the Ruby is that it lost 30% of its brightness in the first couple of hundred hours. There were some metrics posted, if I recall.

Ruby was Xenon. Not sure if that helps.

Tryg had a very nice thread dealing with the Ruby and its various brightnesses before and after bulb break-in at various throws. The thread must have been archived because my link to it is broken now. You might be able to find it though.

I believe the assumption regarding the Ruby is that it lost 30% of its brightness in the first couple of hundred hours. There were some metrics posted, if I recall.

Ruby was Xenon. Not sure if that helps.

Thanks Gremmy. Isnt the Ruby and its Xenon bulb notorious for loosing lumens quicker than UHP bulb projectors?

Thanks Gremmy. Isnt the Ruby and its Xenon bulb notorious for loosing lumens quicker than UHP bulb projectors?

As I recall, there was some debate about that. It was pointed out that all bulbs will deteriorate in a somewhat similar fashion, with the steepest part of the curve up front. What I'm not sure about is the relationship between Xenon and UHP decay.

Thanks for the info guys. I was expecting it to be worse for some reason. According to the chart, by the time you get to about 500 hours, you have lost approx 1/3 of your lamp light which I figured it would have lost 50% by this point.

Yes I was looking at that. I'd consider losing just 30% after 500 hours quite excellent really. With the Ruby I figure I lost well over 50% after the first 500 hours.