For presentations on the move
In today's fast moving world many people are finding that whilst often giving better and more powerful performance, the larger fixed installation projectors are just too bulky and heavy to be considered practical if moving between venues is a requirement. Therefore almost every manufacturer of quality projectors and associated equipment are offering increasingly more advanced and powerful projectors that are of a size and suitable for travel.
Brightness & Resolution
When purchasing one of the smaller mobile projectors you must take into consideration everything as you would when buying one of the larger bulkier models. Firstly the brightness level must be right for the space(s) that you intend to present in. This factor varies a great deal between individual manufacturers but you could expect most portable projectors ANSI lumen rating to fall somewhere between 1000 and 2500.
In terms of resolution most portable projectors fall within the SVGA (800 x 600) and XGA (1024 x 768) categories with some utilizing a wide screen ratio (16:9). As many of your presentations will be created on your PC it may also be worth matching your projectors resolution with that of your PC. The quality of the screen and the ambient light can also affect the picture quality considerably.
Which display type you choose is very important. Often slightly cheaper, LCD (Liquid Crystal Display) are the brightest and give a clear image with good color but tend to suffer from a number of problems, amongst them what has come to be known as the 'chicken wire' where you are able to see a sort of cell structure formed by groups of pixels. The typically more expensive DLP projectors (Digital Light Processing) give incredibly clear pictures with extremely high levels of contrast and seem to avoid many of the problems that face the LCD projectors. One of the few problems encountered by user of DLP technology is caused by the projectors spinning color wheel, sometimes described as the 'rainbow' effect.
In terms of typical prices as I am sure you can imagine that these vary greatly between manufacturers, retailers and second hand suppliers. However, typically you could expect to pay anything between $1000 and $10,000 depending on the make, quality and specifications.