Ultra Short Throw projection: what is it and how does it work?

Large televisions are becoming more and more the norm, but projection still has that extra touch of magic. However, the arrangement of a projector is not obvious in many living rooms. That is the problem that an Ultra Short Throw projector solves. In this background we explain how an Ultra Short Throw projector works and we talk about the pros and cons.

Throw ratio: wablief?

The term ‘throw’ (or ‘throw ratio’) is a of the most important characteristics of a projector lens. It determines the relationship between the projection distance (from projector lens to screen) and screen width. The throw ratio is given as a number or as a ratio. The Dutch term is projection ratio, which is much clearer, but you will not come across it that often. The throw ratio therefore determines whether the projector can deliver the desired image size in your setup.

An example:

• A projector with a throw ratio of 2.5 (or 2.5: 1)
• To a 100 ” To project an image (with a width of 2.2 m), the projector lens must be 2.5 x 2.2 m = 5.5 m from the projection screen.

A throw ratio can also be written as a range, for example 2.5 – 3.5. This indicates the presence of a zoom lens, so that you can project the same image size from different distances. Such a projector is a bit easier to install.

For more information about all the terminology that you encounter when placing a projector, you should read in our article about placing a projector .

Ultra Short Throw is …

What is that actually, an Ultra Short Throw (UST) projector? We can roughly divide projection ratios into four groups. Keep in mind that these are guidelines and not hard rules.

1. Long throw: 2.5: 1 and larger (100 ”image from 5.5 m and further). These are conference room projectors and, given the required space, are rarely suitable for home use.
2. Standard throw: 2.5: 1 to 1.2: 1 (100 ”image between 5.5 m and 2.64 m). You will find most home cinema projectors in this range. They are also often equipped with a zoom lens.
3. Short throw: 1.2: 1 to 0.35: 1 (100 ”image between 2.64 m and 0.77 m). As you can see, these projectors can be much closer to the screen.
4. Ultra Short Throw: 0.35: 1 and smaller (100 ”image from 0.77 m and closer). The projector is extremely close to the screen.

Image via viewsonic.com

Long throw and standard throw will seldom or never be mentioned in the specifications, short throw and ultra short throw will be.

Ultra Short Throw placement

Ultra Short Throw projectors use a particularly strong lens, or often also use a light path with mirror.

The latter in particular can be important if you want to repeat whether the projector fits in your setups. With Ultra Short Throw projectors that use a mirror, the lens is not at the front, but at the rear of the device. The projection ratio takes into account the distance between the lens and the screen. But those who quickly go through the specifications often read that the projector should only be ten centimeters from the wall.

This is of course calculated from the front of the projector (the side that points to the screen) to the screen. So pay attention when trying to find out where the projector should be. Or better yet, search the manufacturer’s website for the manual. There you often find a well-arranged diagram that explains exactly where the projector must be to achieve a certain screen size.

Ultra Short Throw benefits

A UST projector has a number of unique advantages:

• A lot of ordinary projectors you have to hang up, often at the back of the room, and that is extra hassle. A UST projector delivers a large image, is close to the projection surface, and its image shines quite strongly upwards. He can therefore often take the place of a TV, usually even on your existing furniture. That is a lot more convenient in many living rooms.
• Because the projector is at the front, connecting sources can be compared to a television. That means you don’t have to provide a super long HDMI cable to get to the projector. Falling over cables is therefore much less likely, and getting rid of cables is easier.
• People who walk through the image or accidentally blind themselves by looking into the lens are a thing of the past.
• UST projectors are often intended for the living room, and therefore provide a lot of light. Darkening is therefore less critical.

Ultra Short Throw disadvantages

No technology is perfect, unfortunately. Ultra Short Throw projectors also have a number of specific disadvantages. Some of these are not really a disadvantage, but rather things you should pay attention to.

• The extreme lens and mirrors that make UST possible can adversely affect image quality. Slight distortion, or uneven focus over the entire screen, is not uncommon. Traditional projectors usually provide a sharper image.
• Placing a UST projector requires more attention. Due to the extreme angle at which the image is projected, even a tiny shift causes a large distortion on the screen. Correct positioning and carefully checking the focus is a bit more work. However, that is normally a one-time task. You should try to avoid moving the projector when brushing.
• UST projectors rarely have zoom nor lens shift. So there is not much flexibility when placing. Check carefully whether the projector meets your placement requirements: how far should it be from the screen for the desired image, how low should it be below the image.
• Because the projector shines its light almost vertically upwards, it is very important that you use a perfectly flat projection surface. Small bumps on the wall, or wrinkles in the screen, cause clear shadows just because the light comes from below. In the photo below you can see two horizontal lines in the sky, due to tiny folds in the screen because it was rolled up too long. At the top, a tiny wrinkle translates into a crooked image border. Both problems are completely invisible with a normal projector. A stretched screen therefore seems to be the better choice.

• Although they are often equipped with built-in speakers, they rarely produce truly impressive sound. An external sound solution is always possible, but remember that the projector is just where you want to put a soundbar. Maybe your piece of furniture is deep enough so that you can place the soundbar in front of the projector, or it is open with a shelf underneath so that you can place the soundbar under the projector. If that is not the case, you have to find creative solutions.
• UST projectors are often more expensive than a traditional projector.

Screen selection

We already told you that an Ultra Short Throw projector really needs a flat projection surface. has. Considering the purchase of a screen, possibly choose a stretched screen to avoid wrinkles.

Since you are probably looking into the living room, you may be thinking about buying a screen that blocks out ambient light. This way you significantly improve the contrast performance. But beware, make sure that you choose a screen that is suitable for a UST projector. Why? Most screens that block out ambient light dampen all light that does not fall perpendicular to the screen.

Since your Ultra Short Throw projector shines from the bottom up, it would also dampen that light. So look for a screen that mutes ambient light and is suitable for a UST projector. Keep in mind that such screens are considerably more expensive, 1,000 to 2,000 euros for a 100 inch screen is a reasonable indication.

The best viewing food

Finally, just this. Ultra Short Throw projectors almost always aim for a living room environment, where you look at some ambient light. That is why they have a high light output but rather limited contrast. The high light output can cope with the ambient light, and the limited contrast is not a real game breaker since the ambient light would dilute your contrast.

But these choices make these projectors more suitable for sports, animation films and gaming, in short bright colorful images. If you want to watch a film, keep in mind that dark films will not come out optimally unless you do, of course, ensure proper darkening.