InFocus LP70 review

Laurence Grayson ZDNet.co.uk

Published: 22 Nov 2002

Everything seems to be getting smaller these days, and this is generally considered to be a good thing -- particularly when it’s equipment you might be expected to carry around with you. Bearing this in mind, InFocus’s LP70 is a godsend to anyone who needs to give presentations as part of their job, but perhaps less useful for those who need image quality more than portability.

The LP70 isn’t the first ultra-compact projector from InFocus, but it’s certainly the smallest, weighing only 1.1kg and measuring a diminutive 14.9cm by 19.9cm by 6.3cm. Despite being almost small enough to slip in your briefcase, it has a remarkable specification and a wide range of connection options for a projector of its size.

Because they’re smaller, ultra-portable projectors are typically driven by a digital light processing (DLP) engine, and the LP70 is no exception, with an XGA-resolution digital micro-mirror device (DMD) at its heart. As a result, misconvergence is limited to a minimal amount of fringing around areas of detail, and the contrast ratio is high -- quoted as 800:1 by InFocus. A peak brightness rating of 1,100 ANSI lumens should be enough for a presentation without the need to dim the lights or close the curtains, and both analogue and digital signals are supported by the VGA, DVI-D, composite and S-Video ports at the rear of the unit. The projection range is between 1.5 to 10m, with a maximum screen size of 5.3m diagonal at its longest throw.

As is often the case, a small amount of manual phase adjustment on top of the projector’s automatic calibration was required to completely eliminate jitter, although this obviously won’t affect digital signal connections -- for which you’ll have to provide your own cable. Colour uniformity was good, but the LP70 displays the typical flat colour tones and rather low colour gamut of a DLP product. Projections in dark conditions also highlight the strobing (rainbow) effect that’s common to DLPs, despite the LP70 utilising a DDR DMD chip, which cycles the tiny mirrors at twice the speed of previous models. We also found a significant amount of blurring towards the top of the projected image, and greyscale ramps demonstrated some inaccuracies in interpreting lighter shades, with visible stepping as a result.

Its image quality may not be as exceptional as its size, but there’s certainly nothing wrong with the LP70’s control interface or feature set. Digital keystone adjustment of up to 15 degrees is supported, and although it’s not especially resonant and is located underneath the projector, the built-in 1W speaker is a useful addition. Also worthy of note is the menu system, which is both logical and easy to use, with dedicated controls for both keystone and volume adjustment offered by the cursor control panel on the projector’s surface.

With no free space inside the chassis, heat dissipation is often a problem in ultra-portable projectors, often leaving the surface too hot to touch or requiring so much cooling that noise becomes intrusive. Surprisingly, neither is true of the LP70, with near-silent operation and only limited hotspots after extended use. The supplied remote comes with both a rollerball control and laser pointer, and can be used to toggle the zoom and pan functions of the projector. It also doubles as a mouse via a combination signal/USB cable, but it should be noted that on our test notebook the USB port was too far from the VGA port for this to be properly connected. We were also a little irritated by the zoom ring on the lens, which was partially recessed and awkward to use.

It’s apparent that the LP70 isn’t designed for those who want image quality above all else, but it’s one of the best products we’ve seen for the mobile presenter. With a long list of useful features, quiet operation and a reasonable price tag for an ultra-portable, it’s easy to overlook the LP70’s less than perfect image quality.

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