Originally Posted by LarryChanin
As Ron suggests, this whole lumens issue is a matter of managing the expectations of prospective buyers. Based on previous experience many folks were hoping for around 900 usable lumens with a reasonably low drop off with usage.
Originally Posted by zombie10k
I blindly jumped in because of JVC's previous reputation and praise from faithful owners. The new model advertised as 1300 lumens should not put out less light than last years model which has a lower advertised lumen rating.
Originally Posted by Mark_H
Ditto, but also as a current JVC owner I had expectations that were raised not only by my own experience but also by the repeated pre-release claims that the new models were brighter than last years.
Whereas there are a couple of measurements of calibrated out-of-the-box output lumens for RS40s in the 800+ lumen range, I have yet to see a report for any projector in this series measuring calibrated lumens of much more than 500 lumens after 300 hours.
Although my enthusiasm continues to wane with each of these new troubling reports, I haven't completely given up on JVC yet. As I stated earlier in another posting it would be helpful to prospective buyers if JVC clearly stated what the design standard is for both calibrated lumens out-of-the-box and the lumens after a reasonably amount of usage. Without this knowledge it is really a crap shoot whether this projector will be suitable for the buyer's particular situation.
If it turns out that these early measurements are truly representative of what we should expect, then to maintain their fine reputation, it would behoove JVC to offer some sort of incentives to both existing and prospective customers. These incentives might be free spare lamps, extended warranties on the lamps, rebates, etc.
I have started to lower my expectations regarding what amount of usable lumens I should reasonably expect and have started to plan on what additional expenses I would have to add to the price of a JVC projector in order to maintain adequate performance for say the the published expected life of the lamp.
For example, if it turns out we can only reasonably expect 500 lumens after after 300 hours and that produces borderline performance, then perhaps we should add the cost of 10 lamps (3000 hour specified lamp life divided by 300 hours actual usable life). If a lamp costs $400 then that's an additional $4000 added to the cost of owning this projector.
Or perhaps this lower expected usable lumens means I have to replace my screen material to prolong performance. For example, here's an analysis I did of my situation:
Originally Posted by LarryChanin
I used Ron and FLBoy's screen calculators and came up with the following values for my physical layout:For these calculations I assumed that the projector output would drop to 500 lumens after around 300 hours and hopefully stabilize there.
Material FH UM150 UM200 5D D-L HP
Delv. gain 1.25 1.46 1.92 1.87 1.87
2D ftl 14.6 17.1 22.5 21.9 21.9
3D ftl 4.4 4.3 5.6 6.6 4.4
So for this relatively low lumen situation it looks like only the Ultramatte 200 or the Silver 5D would be satisfactory. Selecting the Silver 5D would permit the lumens to drop below 400 lumens and still produce adequate 2D and 3D results of about 16 and 5 foot-lamberts respectively.
So if I were to buy a new Stewart Silver 5D screen I might be able to reduce lamp replacements, or if the lumen decrease stabilized at around 400 lumens maybe the lamp could be used to its full published life expectancy. The cost of new material would probably be around $2000 so I would have to add it to the cost of buying this projector.
Just thinking out loud.