We were interested in Hitachi's CP-A100 projector because it's an attempt to do something a bit different.
Instead of the usual forward-throw system, the Hitachi CP-A100 projects the image backwards and bounces it off a hefty mirror. When the projector powers up the mirror whirrs open, and it whirrs down again when the power is turned off, keeping it out of harm's way.
The advantage of this system is ultrashort-throw. The ratio is around 2.25:1, which means you can park the Hitachi CP-A100 on a desk and it will project an image that's a few metres across from just 1m or so from the wall. The disadvantage is that the mirror collects dust very quickly, and while it's easy to clean we can't help feeling that there is a slightly fragile aspect about this arrangement.
It also means the Hitachi CP-A100 is huge – much wider than the base of an optical overhead projector. You could use it as a portable if you work out regularly, but more realistically it's designed for permanent installation.
The vertical projection angle from the centreline is around 40º, so the Hitachi CP-A100 works best when it can project upwards or downwards rather than forwards. This will be very convenient in some applications, and not so convenient in others.
Connections are on the side of the Hitachi CP-A100 rather than the rear, and a plastic side panel can be fitted to keep them away from poking fingers. There's the usual pair of VGA inputs with pass-through, as well as S-video, composite video and component video.
There's a USB connector but no remote LAN control, which is a limitation given the price. The Hitachi CP-A100's remote is small but functional, and the menu system is very similar to that on the Viewsonic – it's possible the two models use the same chipset. Although there's just a single multi-way menu button we didn't find it too hard to find our way around. Visual quality is good for both video and presentations.
More video contrast to create deeper blacks would always be welcome, and the 2,500 lumen output is mid-range and not quite bright enough for sunlight. But text is very legible and colours punchy and saturated.