Go to Home Page

Click Here to go to Index for All Projectors

 

Product Review
 

Panasonic PT-L300U Three-Panel LCD Digital Projector

July, 2003

John E. Johnson, Jr. and Steve Smallcombe

 

 

Specifications:


1/4 HD (960x540) Resolution
16:9 Aspect Ratio LCD Panels
800 Lumens
Zoom Lens
Digital Keystone Correction
Adjustable Color Temperature
Inputs: Composite Video, S-Video, Component
    Video, DVI, PC, SD
Backlit I/R Remote Control

Lamp Life: 2000 Hours, $360 Replacement
    Cost

Weight: 6.4 Pounds

MSRP: $1,999 ($1,899 from
    ProjectorPeople.com)

Panasonic

www.panasonic.com
 

 

Introduction

The Panasonic PT-L300U is a “1/4HD” Resolution Wide-screen (16:9) three-panel LCD-based digital projector aimed at the Home Theater (HT) market. “1/4 HD” means that the resolution along both axes is 1/2 the resolution of 1080i, the most common High Definition (HD) format. The L300U therefore has a resolution of 960 x 540, less than XGA (1024 x 768), but with a true 16x9 aspect ratio LCD shape, so that it is convenient to use with a 16x9 screen. The other specifications of the L300U important to the HT enthusiast are 800 ANSI lumens, as well as the ability to easily connect to a variety of HT related video sources.

The relatively low resolution of the L300U raises the obvious issue of the “screen door effect (SDE)," the bane of many digital projectors, especially those that use LCD technology. What surprised me (JEJ) was how small the SDE was with the L300U. This is due to an excellent fill factor, which means there is very little space in between the pixels. In fact, it is about as visible as with my Sony 10HT from the same distance, even though the Sony is much higher in resolution. The reason is that the fill factor on the Sony is not as good as the L300U

The L300U is very lightweight (6.4 pounds), so this means it can easily be placed on a coffee table for the evening, and put away after use. It takes a minute or two for the lamp to come to full brightness, and I did not find the fan noise objectionable.

Inputs and Connectivity

The PT-L300U has a complete array of inputs on the rear panel, including composite video, S-Video, component video, DVI, and PC. You can also read SD Memory Sticks on this projector, to view your digital snapshots.

There is a pair of RCA stereo analog audio inputs if you want to have the projector handle both video and sound (in a PowerPoint presentation for example).

Controls

The remote control is very small and is backlit. You can select the input (I used S-Video with my satellite box and component video with the DVD player), keystone correction, mode, and aspect ratio direct from a single button push, while other controls are accessible through the menu button.

The menu system is easy to use. For example, below are shown several menus, such as the main one that comes up when you press the menu button. When you use the up and down buttons to highlight a particular selection, such as Option, and then press Enter, you get the menu for selecting various options that don't need a complete menu page of their own. These include the background color of the OSD (On-Screen Display), where you are placing the projector (for "Desk", the image is right side up, while for "Ceiling", the image is inverted since the projector will be upside down), and lamp power (I used this projector with a Stewart Grayhawk screen, which has a gain of 0.95, so I wanted the "High" setting for lamp power).


The keystone menu lets you adjust the horizontal as well as vertical straightness, so you can place the projector not only below the screen but off to one side. However, it is always better to put the projector in a position that requires only a minimum, or no, keystone adjustments, since you throw away pixels on the sides or top and bottom when you have to use it.

The picture menu lets you adjust all the things that you might want for personal preferences, including color temperature and gamma. Each input has its own memory, so you can adjust each one separately.

The position menu lets you move the image around on the screen, i.e., adjusting the amount of overscan on opposite sides. The Aspect Ratio is also in this menu, and includes 4:3, Zoom (fills a 16:9 screen from a 4:3 original), and 16:9. Each input can be configured separately.

Some of the controls are duplicated on the top of the projector, such as Input and Menu. The Standby/On/Off button is also located here. You can see the small speaker output perforations at the right of the buttons. The left side panel has the main On/Off toggle and a slot for SD Memory Sticks, along with an air intake. The fan blows hot air out the rear.

In Use

You can see from the Lamp Runtime in the Option menu above that I had a very good time with this projector. I watched satellite TV as well as many DVD movies and came to the conclusion that, for $1,999, this is one of the nicest projectors I have ever used. Although it does not have the resolution of my Sony 10HT, it does have enough resolution to completely cover all the detail of DVD movies (740 x 480 from DVD fits within the 960 x 540 of the projector). Some will argue that a higher res LCD panel will allow the projector to scale the DVD image to a sharper picture. However, you have to remember that scaling is a computer's best guess as to what picture detail would be there if it were originally that higher resolution. It is not real picture detail, but rather, mathematic interpretation. I have seen some terrible scaling from 480p (DVD) to 1080i. The bottom line is that I was completely satisfied with the picture quality I got from the L300U with all the movies I watched on DVDs during the test period. It had about the same brightness and a bit more contrast than my Sony 10HT after tweaking, so, again, I think this is a fine unit for less than $2,000.

Although the Panasonic has a DVI input, it apparently does not support HDCP, so some DVI sources may not work with this projector.

Measurements (Steve Smallcombe)

When we evaluate a projector, I not only look at images, I measure the color balance of the projector at various light intensity levels and determine the quality of what is called ‘grayscale tracking’. The idea is that black, white, and all shades of gray, should have the correct ratio of the three primary colors used in video projection, Red, Green and Blue.

Projector meant for HT usage, typically make white by shining just the right proportion of red green and blue light on the screen. Ideally, shades of gray should have the same proportion of red, green and blue as white, but less of each color. What’s important is that this RGB ratio be the ‘correct’ ratio, and that this ratio remains constant as the intensity of the light in the image changes. This ability for the color balance to track properly with the different levels of light intensity is therefore what is called ‘grayscale tracking’.

When testing projectors, I use a system I developed called “SMART”, which measures the intensity of the three primary colors using test images and shows the results in several types of graphs.

After adjusting brightness and contrast on the PT-L300U using the typical Avia images, we measured the Light Intensity data as a function the video input signal, or IRE level, is shown in the chart below. In this case, the ‘Color Temp’ setting in the menu was set to 2.

What we see in the above graph above are traces for red, green and blue which all rise along pretty much the same curve, but with the red curve just a bit below the others. This indicates that with the color temperature setting of 2 on the projector, the color temperature was about 500K to 1000K above the desired color temperature of 6500K. The measured contrast ratio (IRE 100 window vs. black) was 316:1.

As discussed above, a consistent ratio of colors as a function of IRE level is perhaps equally important to overall picture quality as having an absolutely correct color temperature. In the color intensity chart above, it is difficult to separate the details of the color balance at the low IRE level, or how the overall color intensity compares to the ideal for that IRE level. For these purposes, SMART uses two different charts, one for color balance and one for gamma tracking.

In the color balance chart generated by SMART, we can compare the ratios of the various colors at the various IRE levels. In this case, the intensity for the individual colors is compared to the average intensity for that IRE level.

In the color balance chart, ideally all three curves would stay very close to 1 at all IRE levels, indicating that the color balance was the desired one, and did not change as a function of IRE level.

As can be seen in the above Color Balance graph above, the PT-L300U out of the box, shows remarkably consistent color balance at all IRE levels. This chart also shows that the color temperature is a bit high (red is too low) using the initial setting of 2 on the projector. After these measurements, we lowered the color temperature setting to 1. This seemed to give a color balance (not measured) in subsequent viewing that was much more consistent with the desired color temperature of 6500K or D65.

Gamma Tracking

The other thing we need to look at in more detail is gamma tracking, or how the light output of the projector responds to the input signal. As mentioned above, the relationship between input signal level and light output is not linear, as one might expect, but follows an exponential function. The exponent of this function is referred to as gamma for the display. If the projector tracks the desired function properly, then the image will appear as the director intended, with shadow details preserved at low IRE levels and highlight detail maintained at the high IRE levels. If the projector's gamma tracking is off, then details in the image will either be lost, or the image may look flat and have little contrast.

The chart above shows the gamma tracking behavior for the PT-L300U with the gamma control on the projector set to 1. In particular, this gamma tracking graph shows the ratio of the measured combined light level to a theoretical level calculated, in this case, using a target gamma value of 2.2. If the projector is accurately producing the intended light intensity level as a function of IRE level, then the gamma tracking graph will show ratios at all IRE levels that are close to 1. If the projector is putting out less light than the ideal, then the gamma tracking chart will proportionally show a value of less than 1.

In the Gamma Tracking graph we can see that the PT-L300U, with the initial settings, shows remarkably good gamma tracking.

Conclusions

For $1,999, the Panasonic PT-L300U works very well out of the box, and really does not need much, if any tweaking. It has a nice sharp, reasonably contrasty image, with good shadows and highlights, and throws plenty of brightness onto the screen. It is lightweight and easy to set up. For anyone wanting to have an inexpensive projector that will provide great movie viewing, this product is a no-brainer.



- John E. Johnson, Jr. and Steve Smallcombe -

Related to the article above, we recommend the following:

Primer - TVs
   

© Copyright 2003 Secrets of Home Theater & High Fidelity
Return to Table of Contents for this
Issue.
Go to Home Page

 

About Secrets

Register

Terms and Conditions of Use