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Choosing a 19” Monitor to Fit Your Needs and Budget:  The Sony G420S and Hitachi CM721F Evaluated

By Joel Hruska

Date: February 14, 2002

When we reviewed the Sony G420S last year, we remarked on the importance of choosing a high-quality monitor.  After that review, a reader wrote to us and asked us to compare the Sony monitor with the Hitachi CM721F.

I looked up the specifications on that model and was immediately intrigued.  A 19” monitor with a .20 dot pitch for approximately $250?  I contacted Hitachi, informed them of the situation, and they agreed to ship us a monitor for review.  Because the Hitachi and Sony are very different models aimed at very different price ranges, they are not directly comparable, but each serves as an excellent example of a high-quality monitor in its price range and feature set.  We’ve detailed the specifications of each below.

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Monitor Features

Hitachi CM721F

Sony G420

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Monitor Technology Terms

Here are some key terms to remember in monitor technology. These terms are helpful to know when comparison shopping for a new monitor.

Shadow Mask (Hitachi CM721F):  If you’ve ever owned a Lite Brite, you’ve got a pretty good idea of what a shadow mask looks like and what it does.  A shadow mask is a perforated metal grill inside a monitor that focuses and refines the electron beams shot toward the phosphor layer.  This process ensures that the electron beam can hit only one phosphor dot.  This is important because of the sheer number of electron beams firing towards the phosphor layer. Without a material designed to further refine each beam, the screen would be hopelessly blurred or pixel sizes would have to remain gigantic. 

Aperture Grill (Sony G420S):  An aperture grill is designed to perform the same task as a shadow mask, but approaches it differently.  Rather than using a perforated metal sheet, aperture grill technology uses hundreds of thin vertical wires to direct electron beams into their exact targets on the screen.  Aperture grill technology is often thought to produce a brighter, flatter, and clearer image, but at one significant cost. The technology requires the use of a horizontal stabilizing wire located both at the top and bottom 1/3 of the screen.  While normally invisible, these wires can show up distinctly on a white background.  While some users hate them, others (myself included) don’t notice them at all.

Dot Pitch:  Dot pitch is a term used to refer to the diagonal distance between two phosphor dots of the same color on a monitor.  The lower the dot pitch, generally, the crisper the image. 

Refresh Rate:  The refresh rate of a monitor refers to how fast the screen is redrawn.  Higher refresh rates tend to be clearer, easier to read, and cause less eyestrain. 

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A Budget Monitor Done Right:  The Hitachi CM721F

While its $250 price (at Buy.com) puts it well within the budget monitor range, Hitachi has done a very good job on not compromising this monitor’s feature set.  Although the monitor uses older shadow mask technology, its .20 dot pitch gives it an extremely sharp display in text or 2D business work, while its color saturation levels are also quite good for a monitor of this type.

The display remained crisp and easy to use up through 1280x1024, though resolutions above were fuzzy and hard to read.  The monitor also had a tendency to flicker very badly when used in its default mode, though this has more to do with WindowsXP choosing to default to only 60 Hz for a refresh rate than with any deficiency on the part of the monitor.  Simply bumping up the refresh rate fixed the problem immediately.

It’s not uncommon for budget monitors to skimp on warranty support, so we were happy to see Hitachi breaking the mold by offering a five year complete warranty on monitors they manufacture.  This surpasses even the three-year warranty on our top-of-the-line Sony G420S and is a welcome change for a budget product.

One specific area where the Hitachi comes up short is its monitor control system.  In the picture above you can see the two sets of buttons.  Pressing any button activates the Menu system, with one set of buttons being used to navigate the menu system and one being used to adjust various settings.  My problem with the system, however, is that none of the settings are actually labeled.  This is not a major problem (most are understandable based on their icons), but it would have been considerably easier to decipher them had Hitachi shipped a manual along with the monitor.

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General Tips for Selecting a Budget Monitor

Low Dot Pitch:  This is very important.  A monitor with a high (above .25 or .26) dot pitch is going to display blurrier text and images that may increase eyestrain over long viewing times.

Aperture Grill or Shadow Mask?  There are benefits and costs to using either.  Aperture grills tend to be clearer, brighter, and have better color saturation, while shadow masks have no visible wires running through the monitor and are cheaper. 

Warranty:  Don’t buy a monitor with less than a three year warranty unless you’re buying it to be a throwaway piece of equipment.  Even if you’re a high-tech junkie bent on upgrading every 18 months, a good monitor can last through two or three computers before being relegated to a secondary system or replaced with something newer. 

Refresh Rates:  Whatever refresh rate you plan to run in, make sure the monitor supports at least a 75 Hz refresh rate in that resolution.  If you have any kind of eye strain or eye problems, it’s probably best to plan to run in an 85 or even 100 MHz refresh rate. The difference may not seem noticeable after an hour, but if you stare at a monitor day after day your eyes will feel the difference even if they don’t see it.

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Comparing the Sony and Hitachi:  2D and 3D

We used the following configuration for testing both monitors head to head.

AMD Athlon 1.2 GHz

Radeon 8500 using 11/13/2001 drivers

IWILL KT266 Motherboard

WindowsXP Pro

DX 8.1 Installed

We used an ATI Radeon for several reasons.  Radeon cards are generally reputed to have better 2D and 3D image quality than any others and we wanted to make sure the video card chosen could not reasonably be a factor in the image comparisons.  Also, we wanted a video card with dual output support, which the Radeon supports with its HydraVision technology.  Finally, we wanted a card fast enough to ensure that frame rates wouldn’t stutter and affect image quality perception.

We used the following test criteria.

2D

Desktop clarity and legibility at 1024x768x32 / 85 Hz refresh

Excel and Word Document clarity and legibility at 1024x768x32 / 85 Hz refresh

Desktop clarity and legibility at 1600x1200x32 / 75 Hz refresh

Excel and Word Document clarity and legibility at 1600x1200x32 / 75 Hz refresh

3D

Sysmark 2001:  (1024x768x32)

Max Payne (1024x768x32)

Serious Sam (1024x768x32)

The 2D tests were judged on text clarity at both moderate and high resolutions, readability, and sharpness, while the 3D tests were performed primarily to test color saturation.

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The Results:  2D

In lower 2D resolutions, the two monitors are effectively identical.  As the resolution rises past 1024x768, however, the difference becomes more dramatic.  By 1600x1200x32, the Sony holds a decisive advantage over the Hitachi with text that is much sharper and easier to read.  I’ll admit that I have bad eyesight, but in my opinion, 1600x1200 on the Hitachi isn’t all that useable.  I know I’d have a horrible headache after only an hour or so from squinting at it.

Explanation:  While shadow mask-based monitors generally have sharper, clearer text than their aperture grill counterparts and while the Hitachi has a much lower dot pitch than the Sony (.20 vs. .24),  our results show that the Sony is sharper.  The reason may lie in the design of the Hitachi monitor itself.  While the CRT is a flat-screen, it’s a flat screen technology that was adapted from its original curved implementation.  Such an implementation blurs picture quality slightly.  It is also important to note that 1600x1200 is the maximum resolution the Hitachi can reach, while the Sony continues to scale up to 1900x1440. One of our monitors, therefore, is running at its maximum display rate, while the other is still comfortably below it.

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The Results:  3D

Unlike our 2D tests, which were done primarily to test text clarity, our 3D tests were focused on color saturation.  Games such as 3DMark, Max Payne, and Serious Sam all employ vibrant, varied palettes and are excellent tests of color display.  Here, the differences between the two were immediately noticeable at any bit depth or display settings. The Sony G420S offered a visual experience that was much more vibrant, clear, and attractive than its Hitachi rival at all resolutions. 

 In order to make sure our results were not being clouded by other issues, we swapped the input jacks on the back of the card and adjusted all of the monitor and software display settings, including color settings and saturation levels.  Our results did not change. The Sony always appeared to have more vibrant color than the Hitachi. 

Explanation:  The color saturation differences are caused by the aperture grill / shadow mask implementation on each monitor.  Aperture grill technology is known to have more accurate color replication and displays colors more accurately. 

This is not meant to imply, however, that the color saturation level on the Hitachi was bad.  In fact, I thought the display looked excellent in 3D gaming and 2D photo work and only noticed the difference when the two monitors were put side by side. 

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The Sony G420S—Still Top Dog of the High End

When we set the Hitachi and the Sony up side by side to test them against each other, two things immediately became clear.  Number 1, the Hitachi is a great budget monitor and delivers a first-class display for its price.

Number 2:  The Sony G420S is still king of the monitor hill.  In both 2D and 3D, high, middle, and low resolutions, the G420S had a markedly better display quality and color saturation than the CM721F.

Still, that’s as it should be, considering the Sony costs about one and a half times what the Hitachi does (once shipping is included).  Furthermore, as we said earlier, these two monitors are not directly comparable. They are built for different markets.  It might be best to sum the situation up like this.

If you’re looking for a great 19” monitor on a limited budget, but aren’t willing to sacrifice quality for a bigger screen, take a very close look at the Hitachi CM721F.  For a $250 price this monitor delivers fabulous quality.  With a five-year warranty and a high quality display, the CM721F is hard to beat in its price range and feature class.

If, on the other hand, you’re a user who wants to own one of the best monitor made and price is no object, buy a Sony G420S.  You’ll pay for it, but rest assured, you’re paying for quality.

In the end, monitor shopping is like anything else. Take the time to compare all features before making a buying decision. Compare dot pitch, display technology used (Aperture Grill or Shadow Mask), warranties and refresh rates. Make sure that what you buy fits your needs based on understanding the fundamental characteristics of a monitor and which of those characteristics fit in your budget constraints.

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