Brightness
As Art noted in his recent review of another ultra short throw projector, “we still haven’t figured out a good way to accurately measure the brightness of an ultra short projector like this Epson“. Because the angle of the light varies from moderate to steep, and the distance so short, it’s really is a challenge. Thus different reviewers may come up with different lumens values for the Hitachi CP-TW2503 as well as other ultra short throw projectors, even if they are using identical light meters/sensors.
There are several possible ways to measure brightness values with this and similar projectors, but most have real shortcomings. We could measure reflected light off of the screen, at “eye level”, but that puts the screen’s characteristics also into the resulting measurements.
The technique I ultimately used to measure the projector’s lumens output in each of its various color modes should be with perhaps within 10% of what might be expected from a measurement using some “ideal” method (if someone could tell me what that method is). I did use two different techniques (and two different sensors) to measure the relative brightness between the projector’s 9 different color modes and obtained consistent results with both methods.
It should also be noted that with ultra short throw interactive projectors, you can only go only so large in terms of screen size. If the screen’s too big – then it’s too tall for the people using the pens or fingers interactively, to reach up to the top of the screen. For that reason, few ultra short throw interactive projectors are designed to work with screens larger than 100″ diagonal. (Which in a 16:10 format is about 66 inches tall. So, if the bottom of the screen is a low 36 inches off the floor a 100″ diagonal would have the top of the screen around 36+66 = 114, which is 8.5 feet. Few can reach that high without a ladder.
My point is this, for screen sizes around 100″ diagonal or less, something round 2000 lumens can be expected to produce an image capable of dealing with a fair amount of ambient light!
For my measurements I had the projector sitting on a table and projecting a 16 x 10 image that was about 85 inchs diagonal. Factory default settings were used for all color modes.
Picture Mode Measured Lumens
Dynamic 2295
Daytime 2723
Photo 2852
Normal 2209
Cinema 1887
DICOM SIM. 1930
Whiteboard 1351
Blackboard 2423
Greenboard 1973
I found brightness uniformity to be good with a maximum of approx. 20% light variation from the center of the image to the corners.
Color uniformity also looked good when viewing a full screen white image.
While the Cinema picture mode produced very good colors with the factory settings, I found that the brightest modes only offered fair colors. This projector has extensive adjustments available to the user to improve upon the out-of-the-box performance and I tried a few adjustments, strictly by eyesight, to the Photo mode's color temperature (default setting is "High-Bright 7") to create a user settings for the "User 7" color temperature. I reduce the green gain level to -10 and raised the red gain level to +3 and this produced improved colors with only a modest (less than 5%) decrease in brightness. The colors with Cinema mode still looked better, but when a brighter picture is required to help overcome higher levels of room lighting, the photo mode with the custom color temp setting was petty good.
Eco mode decreased the light output by about 40%, measured in Dynamic mode. Hitachi rates the lamp life at 2500 hours in normal mode and 4000 hours in Eco mode. These values are average, but somewhat lower than the lamp life specified by some other manufacturers for competing projectors. The street price on the Hitachi DT-01411 lamp used in this projector is in the $100 to $130 range through a few on-line vendors that I checked.
With most projectors we provide our measurements with the lens at mid-point of its zoom range, but with these ultra short throw projectors there is no zoom range.
Audible Noise
The Hitachi CP-TW2503 is reasonably quiet at full power, and certainly quiet enough to not matter at all, when in Eco mode.
We do not measure audible noise. None-the-less, Hitachi’s claims of 36 db at full power and 29 db in Eco mode are very believable. At full power most home theater projectors tend to be between about 27 and 33 db. Consider that the demand for quiet projectors is much greater in the theater, than a training room or classroom, so any projector that’s really not significantly noisier than a quality home projector is doing just great. .
And of course 29 db in Eco mode is quieter than what many home theater projectors can do at full power. That’s pretty quiet!
Finally, by virtue of the ultra short throw, the projector is right up by the projection surface, far from the audience or students, so they are far less likely to notice than if it was a projector with an average throw distance, which would have it mounted above their heads. Bottom line: noise should not be an issue with this projector.
Sharpness
Sharpness issues have plagued many ultra short throw projectors in the past. Over the years we’ve seen some pretty poor attempts at edge to edge sharpness, and even some that never really look sharp at all. These days that’s more the exception, than the rule, which is a good thing.
This Hitachi ultra short throw projector is extremely sharp, rivaling any longer throw projectors.
Bottom Line on Hitachi CP-TW2503 sharpness: Outstanding!
