One of the perceived limitations of projection displays is that you have to have a lot of room to make a big image. But while “throw distance” is a factor, it’s not as big a factor as it used to be. Today’s short throw projectors can easily create images well over 100” diagonally.
All you need to do is choose the right projector. Here’s a quick guide to doing just that.
[ Skip This: If you’re not keen on all the maths, the folks over at Projector People have a consolidated listing of all the short throw and ultra short throw projectors available – if you need help, their Projector Experts can assist you in your decision and they will do the math for you! ]
Guide to Buying Short Throw and Ultra Short Throw Projectors
The first technical think you will need to understand is “throw ratio.”
In laymen’s terms, you can imagine yourself with a flashlight in a dark room. When flashing the light at the wall from a close distance, you get a brighter and smaller circle. When you move back a few inches, you see the light covers a larger segment of the wall and dims slightly. The mathematical calculation of this effect is called “throw ratio.”
Technically speaking, “Throw ratio” is an equation that explains the distance from projector to screen compared to the screen size. For example, a standard projector might have a 1.5:1 throw ratio. So, to get a 60-inch image; the projector would have to be 7.5 feet back from the screen. Or, approximately 1.5” back for every 1” of screen. Any projector will have this ratio listed in the general specifications.
Currently there are four categories of throw ratio; standard, long, short, and ultra-short throw. We will have to rule out standard and long throw projectors and focus on either short or ultra short throw to get our big image in a small space. Here’s a chart to make this a little clearer.
Throw Ratio Chart
|Projector Type||Throw Ratio||Distance From Screen||Projected Diagonal Image|
|Regular Projector||1.5:1||7.5 feet||5 feet|
|Short Throw Projector||0.6:1||3 feet||5 feet|
|Ultra Short Throw Projector||0.37:1||1.4 feet||5 feet|
So, with an ultra short throw projector, you can get a 5 foot (60”) image with your projector placed just 1.4 feet (18”ish) from your screen. That’s a very big image in a very tight space!
Common Uses for Short and Ultra Short Throw Lenses
Every projecting situation does not require a short throw projector. But there are some situations in which a short throw or ultra short projector is the perfect solution. Small learning spaces, conference rooms where detailed documents are shared, trade shows where a big image gets big attention, and in-home theaters with projector placement limitations, or where the home owners don’t want a big projector hanging from the ceiling.
- Small conference rooms
- Small classrooms (schools, churches, public engagement spaces)
- Trade show booths
- Tight home theater spaces
Short and Ultra Short Throw Projector Pros and Cons
- Light not shining in presenters eyes during presentation
- Less obstruction of image, distracting shadows
- Can achieve a brighter large image from a lower lumen projector (effectively a 5000 lumen image from standard projector would require about 3000-3500 lumens to achieve with short throw)
- No shadow puppets
- Fans can be noisier in small places (look for lower dbs in specifications)
- Less flexible placement options (may have no zoom)
- Installation may require some offset, so less point and shoot than a standard projector
Can Short Throw Projection Offer Lower Cost Digital Signage?
Short throw projection is a growing segment of the projection market. New applications in digital signage have grown out of recent advances in short throw projection.
- Over 90” it is likely to be more cost effective to use a projector vs a large screen LED display because of the weight of the display, installation requirements and overall cost of the unit.
- New 4K ultra short throw units are on the horizon that can produce amazing images up to 140” diagonally, which would provide a cost-effective alternative to very expensive video walls.
If you’d like to know more about short throw as an alternative to LED displays, contact a Projector Expert to get more information.