October 20, 2006

High-Def Projectors for the Value Conscious

What a difference a year makes. I know, we said that last year, but it's still true. If you have been waiting around for prices to drop on a big screen home theater projector, the time has come. The enhanced definition products can't get much cheaper, and the 720p HD projectors are as aggressively priced as ever.

Street Prices Last Year vs. This Year

Home theater projector street prices have dropped significantly over the past year, making you the beneficiary of some great technology for less money than ever before.

480p Prices Year over Year

November 2005	$1299 - $1499
November 2006	$599 - $999
Price Drop	$500 - $700

720p Prices Year over Year

November 2005	$1999 - $2999
November 2006	$999 - $1999
Price Drop	around $1000

If you have been waiting to buy, your patience will have saved you as much as $1,000. Of course that's a year worth of watching your favorite movies, sporting events, and giant screen gaming you have missed out on.

Why Buy an EDTV (480p) Projector?

If you are looking for a big screen TV with improved definition, in widescreen native format, at a VERY low price, you are not alone. A video projector can be used for video gaming, in the family room, or the occasional backyard movie night, and you're not going to have to get a second job to pay for it.

[ Photo: Madden for Xbox displayed on WVGA Hitachi ED-PJ32 projector from progressive scan DVD player. ]

Video projectors will get you the largest images (we're talking a 200-inch screen) for the buck. You also gain portability (take it anywhere at just 4.8 lbs.), widescreen native format with progressive scan (EDTV) quality resolution, and a TV that can be stored away on a bookshelf when not in use.

Benefits of a 480p Projector Over a Traditional CRT TV:

With the push towards flat screen technology, you might think that a 32-inch CRT television would be a very cheap purchase. In reality, they still typically cost in the $450-$700 range. To summarize:

• Competitively priced from $595 to $999.
• Online purchases cheaper due to sales tax savings and reduced shipping.
• 480p (progressive) superior to 480i (interlaced) signal for fewer video artifacts.
• Native resolution same as progressive scan DVD players and game systems like the Xbox, for better quality images.
• Flexible image sizes, including much larger viewing size (up to 92-inches for best results) than the fixed 32-inch conventional TV.
• Weighs a lot less, so it is portable and can be easily put away when not in use.

Read more about 480p projectors here »

720p Drops Below $1,000!

High-definition has its price, and that price can now be as low as $999 bucks. The Hitachi PJ-TX100, for example, is a close-out item that can now be had for a steal. In a recent review from Audioholics they wrote:

"For $2999 this projector would have a TON of competition and would be difficult to recommend - but with a street price of $999 it's a no-brainer. The Hitachi provides lots of features and an incredibly detailed lens system that delivers precise resolution and clarity. This is a projector I think can fit into any entry-level system and provide years of enjoyment. The remote gets our "kudos" award for hitting all of the basic requirements and basic 2:3 pull-down features means that even standard definition video will be passable on this system. The PJ-TX100 is a solid performer, so be sure to put it on your "short list" when shopping for a sub-$1000 projector that works well in the home theater environment."

And that's the word.

This should be a very big year for video projector sales. The word is out, and the prices are competitive (and often better) than CRT and RPTV alternatives. Plasma and LCD have the sleek design, and space-agey-coolness, but a video projector has one big thing going for it: The image, a great big image.

projector, projectors, Home Theater, technology

October 17, 2006

What's In a Lens?

Tech News: What's In a Lens?

Let’s face it; most of us tend to take projection lenses for granted. It’s rare that our projector purchase decision hinges on the type of lens. Nope, we’re usually shopping for (1) brightness, (2) resolution, (3), size and weight, and (4) price!

When you think about it, a projector is only as good as the lens in front of it. All the resolution in the world won’t do you a bit of good if the lens has problems with uniform focus, chromatic aberrations, and lens flare.

Although projection lenses have been manufactured for over a hundred years, the science and art of lens design continues to evolve. The projection lenses we use today are significantly improved over those used on the first LCD projectors of a decade past. They have to be, because projectors have gotten smaller and brighter.

Primary Lens Specifications

A projection lens has two primary specifications – its focal length (usually expressed in millimeters, or mm) and its aperture (usually expressed in f-stops). The ratio of the longest focal length to the shortest is called the zoom or throw ratio. For example, a zoom or varifocal lens with a focal length of 23mm to 46mm has a 2:1 zoom ratio.

That throw ratio also gives you some clues about how far the projector must be placed from a projection screen to fill the width of that screen. With a 2:1 throw ratio, the projector must sit at a distance that is twice the width of the screen. With a 1:1 setting, the projection distance equals the screen width, and the projector can be positioned even closer by using super short-throw lenses, such as .95:1 and .85:1 ratios.

Lens Aperature

The lens aperture determines how much light will pass through to the screen. Lower aperture numbers mean a brighter image; higher aperture numbers mean less light will be passed to the screen, unless a brighter lamp is used.

The lens aperture also determines the lens’ depth of focus (also called depth of field). Here, the low aperture number means you’ll have a very narrow depth of focus. That won’t be a problem in most cases unless you are projecting at a horizontal or vertical angle to the screen, or projecting onto a curved surface. In those cases, you’d want a smaller aperture with a higher f-stop number.

Lens Focal Length

The lens aperture is also affected by the focal length. It’s easy to manufacture a short focal length lens with a wide aperture, but maintaining that aperture with a long-throw lens would mean increasing the surface area of the glass, adding size and weight. At some point, this process becomes impractical and smaller f-stops are used.

The relationship of image brightness to lens apertures is straightforward. As you increase the lens aperture by one f-stop, image brightness will be reduced by 50%. Conversely, opening up the lens aperture by one f-stop doubles image brightness. This adjustable aperture (or iris) technique is used to improve black levels on the Sanyo PLV-Z4 when viewing scenes with low-luminance content.

What About The Other Specifications?

When a projection lens is evaluated for performance, certain characteristics are carefully inspected and measured. Let’s start with chromatic aberrations, which are misalignment of red, green, and blue images due to different focal lengths of red, green, and blue light. They are almost impossible to eliminate completely in any projection system, but can be minimized with multiple-element lenses.

Convergence

Any convergence error inside an LCD projector, due to misalignment of the red, green, and blue imaging panels, will be worsened by chromatic aberrations. You might see a white line with a blue or red edge to it, or a color “ghost” around objects with sharp edges.

The lens can exhibit spherical aberrations, or defects in the curved optical surfaces. Light rays do not bend in a predictable manner, which then causes problems with uniform image focus. Contrast can also be lowered.

Lens Flare

Another problem is lens flare, which resembles a soft, halo-like glow on certain parts of the projected image. This reduces image contrast and sharpness, and is caused by unwanted refraction and reflection of light rays within the lens. Ideally, all light rays enter the lens and are focused onto the screen. In reality, some ricochet around inside the lens and may even be reflected back towards the condenser or light integrator, lowering contrast and raising black levels.

The geometry of the projected image can change as the lens is zoomed in and out, causing the sides of the image to curve inward or bow outward. This phenomenon is known as pincushioning and is often seen on low-cost lenses or projectors. It is often tied to spherical lens aberrations.

To sum up, not all projectors are created equal when it comes to lenses! Sanyo LCD projectors use high-quality optics to provide the best image quality possible. See for yourself!

Click here to see the complete line of Sanyo projectors.

[ From Sanyo Projector Intelligence Newsletter April 2006 ]

projector, projectors, Business Projector, technology,projector lens, projector lenses