Originally Posted by purduesd
OK, for arguments sake:
Let's take my primary wish scenario and put some numbers in ....
150" AT drop down screen (1.0 gain )
12' viewing distance (because screen will go in front of soffit)
Dark walls, ceiling, trim
The JVC NX5 vs the Epson 5050up (both with zoom slider all the way to max wide angle)
Both have about the same throw of under 15'
JVC 28 fL
Both are plenty bright for nighttime dark room viewing right?
What am i missing, because the calculator math is different than some of yours... (Im not being smug here, trying to understand)
Estimates are not always accurate, the lamps especially could have some variation in brightness.
The estimates from PC calculator are in the brightest mode I think.
Measurements taken by reviews site can also be inaccurate or differ due to testing methodology, human error, etc. For instance on a review of a 5040UB, PC measured ~3500 lumens in it's brightest mode. The 5040UB is very similar to the 5050UB, brightest mode is around 2500.
150" 16:9 screen has 66.71 ft².
Measurements from these two sources:
The NX5 is rated 100 lumens less than the NX7.
Lamps loose around 25% of their brightness in the first 500h, and in a linear fashion afterwards until the rated hours which is half of it's original brightness.
Using the projector on High lamp will increase the noise level considerably on both the Epson and JVC, as well as wear out the lamp quicker.
On most projectors the highest preset setting has a green tint. The Epson has it (Dynamic), but the JVC review does not mention it, maybe it doesn't have it.
The general recommendation is 10-15fL for SDR, and for HDR it depends on the tone mapper. I've seen 20-22fL for the NX series, not sure about the 5050UB, 30+fL in general. NX5's DTM is better than the Epson's. If you browse the forum you'll find users with large screens and happy with low fL, but that's not the general consensus.
Epson has a Medium lamp mode that JVC's doesn't, but I've seen comments that claim that JVC's Low lamp is similar to Epson's Medium.
4K video most of the time also has an expanded color gamut. The Epson can cover ~87% of this gamut and over 100% with the help of a filter. This filter is engaged in the Cinema and Digital Cinema presets and reduces light output by 50%. The NX5 covers ~90% and does not have a filter.
Just take a preset and a lamp mode's lumens and do the math, but without seeing what each preset looks like it might not be easy.
For instance, Natural preset in Low lamp on the NX5 would be around 900lm. 900 / 66.71 = 13.49fL
After 500h 10.11fL. Half bright 6.74 fL.
On the 5050UB Natural preset in Eco lamp is 1438. 1438 / = 21.55 fL
After 500h 16.16fL. Half bright 10.77fL.
This calculator can be used, but does not have the NX5. Under the Display tab the brightness at a certain lamp hour can be selected. For 500h I've set it to 25%.