Ultra-portable data projectors

 I've been looking around at very small data projectors for mobile presentations...

Link to Toshiba TDP-FF1A - Google Search

Found this particularly interesting development - it's been around for a while and has not exactly taken the world by storm so obviously has limitations.

What really prompted me to write this short piece were some observations about manufacturers' claims and specs. I mean...just what is ultra-portable? No, I'm not looking for a set definition, and I know that marketing people take liberties...but describing a unit that weighs 6.9 pounds(!) as ultra-portable is stretching things a bit...mostly my arm with the weight...and that's without all the extra clobber like case, cables etc. My own personal limit would be 2.5 lbs but that is arbitrary.

The next thing that I found interesting to look at was the noise issue. One of the main uses for ultra-portables is noise, since you are likely to be close to it giving presentations to small groups on a table top. A noisy fan is very disruptive and I regard this as a crucial point when choosing. The good news is that most manufacturers do quote a noise rating as part of the spec. What I have not been able to find is how these ratings are made. Since it is an engineering specification, there should be a standardised measurement method. But I suspect, as with many things in marketing, that some license is taken with this. Decibels and noise in particular are very variable depending on measurement technique so I really wonder if the numbers mean much.

One important point to remember is that small differences are big differences in noise. A 3dB difference is a doubling in power so if the noise is measured in some electromechanical way, 3dB is lots. On the other hand, it's not much in terms of perceived audible difference. Most people have difficulty in discerning a difference of 2dB. Most projectors are rated between 30 and 38dB - but while it may not look like much, this can be very significant. More importantly, the quality and frequency of the sound is very relevant. Some noises can be ignored more easily than others.

Brightness. Small groups do not need a huge auditorium power projector. But they do tend to meet in rooms with windows so brightness is important. Most manufacturers do quote a brightness rating in ANSI lumens. The ANSI part is important as it states that a standard measure process has been applied. Generally speaking, you need 1200-1500 lumens for a well lit room. Quite a few ultra-portable projectors skimp on that.

To be fair, brightness also varies with distance (or by the square of the distance). So placing the projector closer to the screen, which is often what you are doing with a table top small group presentation anyway, helps with getting more brightness. Actually, it varies more with image size I guess so we should be accurate about this since we are grumbling about accuracy.

A few manufacturers do show projection size according to distance. This depends on the angle of zoom (think the reverse of angle of view for a camera lens). So more zoomed out means a bigger but less bright image. What this all boils down to is that if you keep the projected image size small, you can get away with needing fewer lumens.

Test things out. Try a few before you choose, or get a money back/return arrangement in case you are not satisfied.