Epson Pro L1755UNL Laser Projector Review- Special Features

Epson Pro L1755 Projector Review – Special Features: Laser Light Engine, Pixel Shifting 4K and 2K Content, Color Accuracy

LASER LIGHT ENGINE

The ProL1755UNL, like all the models in the Epson Pro L series, uses a dual blue laser light engine. One blue laser ultimately hits phosphor wheels to generate red and yellow beams, while the other blue laser handles the blue component. As with all 3LCD projectors a dichroic prism is used to re-assemble the three different colors into a single full color image.

Epson laser light engine for L1755UNL and their other L series laser projectors

Epson rates their laser light engine for 20,000 hours at full power. As with a lamp-based system, the life rating is the point where 50% of the brightness has been lost. Once the light engine has run for 30,000 hours, the brightness will be reduced to 30%.

There are four modes to adjust the brightness output of the laser light source:

  • Normal which sets the brightness to maximum which is ideal for conference rooms, auditoriums, lecture halls, etc.
  • Extended mode sets brightness to 70% of full power and extends the life of the laser light source. This is ideal for darker environments with less ambient light such as museums and art galleries or where a reduced maintenance cycle is also a desired benefit.   
  • Quiet mode also sets the brightness to 70% but it reduces the fan speed which dramatically reduces fan noise. This is great for quiet environments like libraries, art galleries and theaters. I used this mode for most of my viewing in my home theater. When set to quiet mode, the fan noise was barely louder than my reference theater projector while delivering nearly 5 times the brightness. 
  • Custom mode allows you to adjust the brightness level between 30% and 100% of full power, giving you the ability to greatly reduce the brightness and extend the life of the laser light source. For example, at 30% brightness level, the laser light engine is rated for 71,000 hours while still outputting brightness a regular home theater projector could only dream of.

When the L1755UNL encounters a “black frame” of information, it can shut down the laser engine completely projecting a true black frame. Unlike lamp-based projectors, the power consumption is greatly reduced when implemented.

Epson’s simplified chart showing laser light engine’s life expectancy under different options

PIXEL SHIFTING

While pixel shifting can’t match the resolution of a true 4K projector, it does increase sharpness and detail compared to a standard 2K projector.  The Epson Pro L1755UNL projector can accept up to a 4K@60P signal. When fed 4K content, this Epson projector uses pixel shifting to fine tune the image to more closely resemble 4K. Pixel shifting fires each pixel twice by shifting the location by 1/2 pixel diagonally. Combined with good image processing, it does a very nice job emulating the original 4K content.

The included images show the difference between image enhancement modes. While there’s noticeable improvement with pixel shifting on 2K content, it is even better when the Pro L1755UNL is displaying 4K content.

When viewed in person, the actual differences on the screen are greater than what you are seeing on this site. This is because of the heavy compression and scaling of the images for the web, so the differences you are seeing when viewing it on this website will be less noticeable. As you can see in the above images, when you compare 4K content with pixel shifting turned on and off, the difference is impressive.

Small type and fine details that can’t be discerned on a basic 2K – WUXGA (or 1080p) projector can often be resolved with pixel shifting. It is enough to make a real readability difference on CAD, engineering and scientific drawings renderings and anything else demanding max detail.
It is only when you do a side-by-side comparison between a true 4K projector versus a 2K pixel shifting projector that the resolution difference is noticeable. The images below show the resolution difference between my true 4K projector and the ProL1775UNL which is utilizing pixel shifting for comparison when displaying native 4K content.

So how do I choose between a pixel shifting projector like the Epson ProL1755UNL and a true 4K projector? To make a wise decision you must factor in your budget, what you are watching and from where you are watching it.

True 4K high lumens projectors cost at least four to five times as much as their 2K counterparts. Consider this, a Sony 8,000 lumen true 4K laser projector retails for $60,000 while an Epson pixel shifting 16,000 lumen 2K laser projector, like the ProL1755UNL, cost about 1/3 of that amount.

In many situations, the content lacks the detail required and is viewed at a distance where the difference between 4K and pixel shifting cannot be perceived. So, if the image is going to be viewed from fairly far away, a brighter, less expensive pixel shifting projector like the ProL1775UNL is probably a better solution than a true 4K model for that application.

NOTE: Pixel Shifting requires a lot of processing so it cannot be combined with some features like edge blending, and Creative Frame Interpolation, but even some more basic things, including some types of noise reduction.

Some advanced features are disabled when Pixel Shifting is applied

PROJECTION MAPPING AND EDGE BLENDING

First let’s talk about Projection mapping which is masking the image digitally to light up non-traditional, often three-dimensional objects. This is used often at concerts, museums and other digital signage applications. While there are powerful software-based projector mapping solutions, the ProL1755UNL has a Geometric Correction feature which lets you correct image distortion caused by projecting an image onto a curved or right-angled screen. You cannot combine traditional H/V keystone correction with the other image shape correction methods with projection mapping.

If you need more light output or want to utilize multiple projectors to display a larger, wider aspect image, the ProL1755UNL is equipped with several features to make that goal easier.

By utilizing Edge Blending, you can split an image over multiple projectors and display it as one large image while reducing the hard transition from one projector to another. Under the Blend Range menu’s sub-setting, you can fine-tune the blend’s starting position and the width of the blended area. You can use the projector’s Black Level setting to make the difference even less noticeable. The result is an image that looks seamless, like it’s being displayed by a single projector. However, Edge Blending can’t be combined with pixel shifting but that is okay in many situations where maximum flexibility is more important than absolute resolution.

The Epson also has the necessary controls to match color and brightness across up to nine projectors. And, thanks to Epson’s Constant Brightness feature and “one button” auto calibration, these projectors should all be able to work together seamlessly for 10,000 hours or more with little to no adjustments required.  

The laser light engine offers a significant advantage over a bulb-based system in a long-term projector installation. If multiple lamp-based projectors are used, not only would the bulbs fail regularly, they will dim at different rates, causing color and brightness shifts. You would need to replace all the bulbs each time one failed to ensure similar characteristics and some additional calibration would probably still be required to produce ideal picture quality. 

For Edge Blending application, laser projectors make for the ideal solution. Unfortunately, it’s not practical to fully test the ProL1755 projector’s Edge Blending feature in my test room but based on the available adjustments and the tradeshow demos I have seen, it looks like an easy-to-setup, capable solution.

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