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Lens Throw and Lens Shift

Posted on October 10, 2013 by Art Feierman

The InFocus IN72 lacks variable lens shift, which, when present, simplifies vertical placement of the projector. This is typical of DLP projectors selling for under $3000, not just entry level projectors. In fact, to get lens shift you have to step up your budget a bit, out of entry level, into a couple of the lower cost, higher resolution LCD home theater projectors. As of this writing, the least expensive DLP projector with lens shift is $2999 selling price.

One area of compromise that InFocus made to the IN72, compared with the IN76, is the zoom lens. Instead of a 1.3:1 zoom ratio, this lens offers only 1.2:1. That gives you 20% distance flexibility to the screen. 20% is probably the most typical of entry level DLP projectors, although LCD projectors typically have more range.

As far as placement distance goes, to fill a 100" diagonal screen, you can place the IN72 as close as 12.8 feet and as far back as about 15.4 feet. Many people, who would otherwise place the projector on a table or ceiling mount, may find the throw distance long enough to place the projector on a shelf in the back of the room.

When mounting the projector you will need the projector (actually the center of the lens) to be just slightly above the top of the screen surface. If sitting on a table, or shelf, the center of lens will be a few inches below the bottom of the screen. This is a common amount of fixed lens shift, that works well for most users. If you can place the projector on a shelf at the rear, but want it high up you will need to invert the projector, as you would if ceiling mounting.

Pixel Structure, SDE and Rainbow Effect

Pixel visibility on the IN72, is typical for a DLP projector, meaning that they are far less visible than on competing LCD projectors. Sitting about 1.5 times screen width (that works out to just less than 11 feet back with a 100" diagonal screen, is far enough that pixels will not normally be noticeable. The exceptions are in large stationary bright images, and on things like credits. The distortion of the pixel structure and small details in areas like grass, that can make the grass look wierd, is not likely to become an issue at that distance. If you really want never to be able to detect the pixels (except maybe on those movie credits, think sitting more like 1.9 or 2 times screen width, but most will be content at 1.5 or 1.6 times, some won't mind the pixel structure at all regardless of where they sit, even very close.

The image below showing the text "Schuykill" is from the HD image of the boathouses on the previous page. Here you have a zoomed in closeup so that you can see the pixels, but checking out the full sized image, gives you an idea of how small they really are from normal viewing. The same "Schuykill" image is found in most recent reviews. Since the image of the text itself varies frame by frame, and I cannot pause my D-VHS deck on a specific frame, there will be differences from one image to the next in terms of "jaggies". This would not be projector specific. Bottom line, you are looking for the size, and visibility of the pixel structure, not the actual edges of the lettering.

On to the Rainbow effect: The IN72 home theater projector uses a 4x (four times standard) color wheel (unlike the IN76 with a 5X speed wheel). 4X wheels are now standard on entry level home theater DLP projectors, and are found on some more expensive ones.. With a 4X wheel only a very small percentage of viewers are susceptable, at all, to the "Rainbow Effect". (There are no official numbers, but probably well less than 5%.) If you are one of those very few, you are likely to go with an LCD projector instead. There are one or two LCD projectors in the entry level catagory, such as the Epson Home 20. Otherwise you are looking at more expensive higher resolution LCD projectors as well as more expensive DLP models with 5X wheels. But, again, the rainbow effect is seen by very few, and annoys even less.

Light Leakage

I was surprised to find what appears to be some light leakage coming out of the lens, and creating a very dim amount of extraneous light hitting parts of the lower right corner of the screen and overshooting beyond to whatever you have to the right of your screen. The image below has contrast and brightless cranked way up so that you can see the light. Again it is very dim, and I doubt that many would notice it at all, but as a reviewer, I figured I should point it out. It apears from just inside of the scren as almost round, with 80% of it outside to the right. I have a very bright LCD display on this laptop, as I write, and I can hardly see it, but it's there! Still, no big deal!

Other than that,the IN72 is very clean, in regards to light leakage. No issues here at all. You can spot the tiniest amount of light coming out of the sides of the projector, but far less light overall than most other projectors.

Audible Noise Levels

InFocus does not publish a spec for noise levels, however from using the projector, it is very quiet in Whisper mode (low power), although not the quietest I've worked with. In my viewing room with the projector sitting about 4 feet behind me (but I sit in a high backed "captain's chair") I never noticed the fan except when the sound track was extremely quiet, and only when listening for it. In full power mode, as expected, the IN72 is significantly noiser. As related to the competition, I found the noise levels on the IN72 to be similar to the BenQ W100, although the BenQ is slightly lower pitched (better). I don't find noise in low power mode to be an issue for all but the pickiest. In full power, if you demand silence, few projectors will come close to satisfying you.

Projector Brightness

Despite the relatively low brightness claims (720 in whisper, 900 in High Bright mode), the IN72 is fairly typical. In best mode, with gamma set for Film, I measured 359 lumens. With the same Film Gamma that should be just over 400 lumens in High Bright mode, and much brighter still if you set the projector for Bright Room mode. Of the DLP's in this class, the InFocus looks fairly average. In fact in the couple of side by side images with the BenQ W100, in this review, you can see that there is little difference in brightness is nearly impossible to detect (the differences you see are more related to gamma than brightness.

Here's one of those images, from The 5th Element. In an attempt to get both images as close to each other in brightness, for comparison purposes, the BenQ projector (right) is iin low power mode, while The IN72, on the left is in bright mode.

One tell-tale that the IN72 (thanks to bright mode) is slightly brighter on this side by side photo, is by looking at the pause/frame advance icon in white on both images near the top right. You can see in the larger version that the graphic is sharp on the BenQ but blurry, due to slight overexposure in the InFocus.

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