Calculating screen size and projection distance made simple

So, you’re thinking about getting a projector and want to know where the projector needs to be to fill the screen or to get a certain size image.  Or you know exactly where you want to install the projector but don’t know how big the image will be at that distance. No problem! 

Introducing the Installation Triangle


If you have any two dimensions on the installation triangle – you can calculate the other one. 

So – taking our UHD40 4K projector as an example.  This has a throw ratio (TR) of 1.2~1.59:1

If we want a 100cm wide screen – we multiple the screen width by the TR = projection distance of 121cm~159cm

If we know where we want to place the projector (ie 121cm back) and want to calculate how large the image would be – we divide the distance by the TR which gives a screen width of between 76.1~100cm (depending on how much you zoom in the image).

If you don’t know exactly what model you need but know your screen size and where the projector needs to be – you can calculate your TR.  This will help you to narrow down which models would fit your room.


But put that calculator away!

Optoma has a brilliant distance calculator on its website that does all the hard work for you! Simply put in one dimension and the calculator will do the rest. 


Where you place the projector is an important part of choosing the right projector

Short throw and ultra-short throw projectors can be positioned very close to the wall and still provide a big image on the screen. The benefits here are no shadows and they tend to be brighter by being closer to the screen or wall.

Normal or standard throw projectors sit further back and tend to mounted on the ceiling and above/behind where you would be seated.



Top Tip

If are thinking of placing your projector on a shelf near to the ceiling – don’t.  You would need to tilt the projector which would distort the image shape.  Install the projector under the shelf rather than above -  ideally with a universal mount.



How 3D glasses work

3D can be an exciting immersive experience.  We thought we’d break down the two 3D glasses technologies available and give you a run-down on what each technology is called and what they do to produce a 3D image.

3D glasses work by displaying a different image to each eye. Our brain then merges each image into one, but with 3D characteristics. This, in turn, “dupes” our brains into thinking that it is seeing an image in 3D, so it creates an image with depth for you.


Types of 3D Glasses

There are two types of 3D glasses – Passive Polarized & Active Shutter. Both achieve their 3D visuals in a different way.

Passive Polarized glasses look a lot like sunglasses, not unlike what you get when you visit the movies. The TV or projector has a special filter that polarizes each line of pixels. This filter makes the odd lines on the screen only visible to the left eye, and the even lines only visible to the right. Your brain then interprets the image as a 3D image. Without the glasses, the image looks normal. A downside to this system is that the image is not Full HD 1080p as it halves the amount of pixels visible.

Active Shutter glasses use batteries and a transmitter that syncs with the rapidly moving shutters for each eye with the on-screen display.

The 3D image resolution is the same as the 2D image displayed on the same screen. This is because the left and right eye images are shown in sequence rather than at the same time. The 3D glasses sync with the projector's refresh rate to sequence the images that produce a 3D image to the viewer.


Optoma 3D Glasses

All of the projectors we produce at Optoma are active 3D. They can however be converted to passive 3D if required with the use of a silver screen and a passive 3D filter.

At Optoma, we recommend two different types of Active 3D glasses:

ZD302 – These glassed incorporate DLP Link™ technology which use line of sight to the screen to produce a 3D image. If you look away and then back to the screen, the glasses will display a very slight stutter as they re-sync with the projector.

ZF2300 – These 3D glasses use RF (Radio Frequency) technology to sync with the projector. RF synchronisation eliminates any potential sync issues and many glasses can be paired to the same projector. As these glasses need an RF emitter to function you will need a “ZF2300 starter kit” that includes an emitter and a pair of glasses.



Full 3D vs 3D ready

If your projector is Full 3D it can play 3D content from a DVD player or games console - you just need the glasses.  If the projector is '3D ready' - it is still possible to watch content on 3D but you would need additional equipment including a PC with quad buffered graphics card and professional 3D software through which you would play the content.  This is not recommended for general home use.


Create a spectacular Christmas display

Are you dreading the annual tussle with the tangled ball of Christmas lights?  We are too!  So we have put together some suggestions on how to create a stunning seasonal spectacle with a twist.


Project onto your windows

Simply line your windows with tracing paper, a frosted shower curtain, a thin cotton sheet or frosted film and you have a screen to project your decorations.  This could be a Christmas tree, a festive greeting or even an elves workshop!




For the 2018 Gadget Show Christmas Special presenter Jon Bentley showed how to create a magical Christmas display by projecting AtmosFX digital decorations onto the Gadget Show house windows.  We used a £3 shower curtain from Dunelm Mill and beamed the elves workshop via our ultra short throw Full HD HZ40UST laser home entertainment projector. AtmosFX creates digital decorations with fun and entertaining animated characters and stories for Halloween, Christmas, Valentines Day and other special occasions.  Watch again on My5:


Don’t get the needle

If you are fed up schlepping in the tree from the garden centre (or loft) and spending hours arranging baubles – why not project your tree or decorations




Optoma helped Craig Charles projection map his Christmas tree and create a snowy scene on a mirror, using the GT1080Darbee short throw Full HD projector and Optoma’s Projection Mapper app, for the 2017 Gadget Show Christmas special.  Watch again here:


Project decorations straight onto your house

If you have a shed or a friendly neighbour opposite, you could project your Christmas lights straight onto your house.  This avoids battling with blown bulbs and just needs a bright projector, images or animations to project onto the house and somewhere secure under cover where you can place the projector.  Your house would be the envy of the neighbourhood!


Richard Ayoade, showed how to do this in the Gadget Man Guide to Christmas when decorations and animations were projected directly onto the Gadget Man house. 


Have a very merry 4K Christmas

More films, TV and sport will be broadcast in 4K this Christmas than ever before. Bring a cinematic experience to your home and enjoy your favourite festive flicks in 4K.  Join the 4K party this Christmas!


Is it time to join the 4K party?

We often get asked “Should I upgrade my projector to 4K or stick with Full HD? Is there a significant enough improvement in image quality to warrant paying more?”  So, we’ve popped down a few pointers that might help you to choose. 

What is 4K? 

Put simply, 4K provides four times as many pixels on your screen than Full HD 1080p.  And the greater the number of pixels – the better the image quality will be. 

The Consumer Technology Association (CTA) defines 4K UHD resolution as 3840 x 2160 or greater than eight million addressable pixels.  Full HD resolution has around two million on-screen pixels. 

With the full 8.3 million on-screen pixels, Optoma’s 4K UHD projectors meet the Consumer Technology Association (CTA) requirements for 4K UHD and CTA High Dynamic Range (HDR) compatible display standards.

Will I notice the difference?

“So, there are over eight million on-screen pixels but will it make a difference to what I can see?” 

The additional pixels from 4K bring increased depth and light and shadow detail to imagery but if you are viewing this on a small screen and depending on how far from the screen you are sitting, this extra detail may not be visible. 

That’s why the large imagery produce by projection is where you can really see the benefits from this added resolution.  Any imagery bigger than 65” will look better with 4K UHD resolution.  4K allows you to sit closer to the screen without individual pixels being visible.  Filling more of your visual field yields greater immersion.

“But is the content there?”

More films, TV and sport are being broadcast in 4K than ever before. Sony and Microsoft both have consoles on the market that can render games in 4K. Most major blockbuster movies are being released on Ultra HD Blu-rays, and streaming companies like Netflix are releasing more 4K content than ever before. 

A 4K projector today will future proof your viewing tomorrow.

The price is right

With the improvement in technology, the price for 4K projectors and TVs has reduced massively over the last couple of years with 4K budget models now available.

So with content more readily available, and its ability to bring content to life with incredible detail, colour and contrast, is it time you joined the 4K party? 

Check out Optoma’s range of 4K UHD projectors here:


Cutting through the confusion of large displays

To achieve a large image, installers have a myriad of options.

Should they go projection?

This is, by far, the most cost effective and simplest way to attain a large display image, especially if high resolution is required. But is there too much ambient light? Would a high brightness laser projector cut through this?

Should they install a Large Format Display (LFD)?

For a large image a single LFD screen is heavy, cumbersome and expensive.  They could create a videowall with multiple LCD screens but this has the downside of bezel frames around each screen slicing through the overall image.

Or they could look at an LED display. 

LED displays are made up of slim LED panels installed flush beside each other to create a seamless display with no bezels disrupting the image. They are expensive compared to projection but large LED displays are becoming far more comparable in cost to similar size LFD videowalls.

But which one is best?  We catch up with Ross Noonan, Technical Product Specialist at Optoma, to try to cut through the confusion. 

Q: So, which solution is best Ross?

A: It depends on the environmental factors.. In a high ambient brightness environment, projection will look washed out but if the ambient light is not too high or light could be controlled, projection may be the best (and certainly the cheapest) option. 

If the ambient light is high and you want large seamless imagery without bezels interrupting the image, you may need to look at installing an LED display. 

Q: That sounds complicated.

A: It doesn’t need to be.  You need to ask more questions perhaps than for a regular projected display but honing down the requirements, by asking a number of key questions, will help you choose the right solution.

Q: What questions do I need to ask when looking at LED displays?

A: Do you need a permanently installed or mobile solution?

Is it for indoor or outdoor use?

How bright is the environment where it will be operating?

What size and aspect ratio do you need?

What content will you be showing?

Where will the audience be in relation to the display?

How accessible will the display be if it needs maintenance?

Q: Can you use LED displays in full sunshine?

A: Yes you can.  Brightness of LED panels is measured in Nits.  A single Nit emits over three times more light than a single lumen.  LED panels can be scheduled to change the brightness at different times of day. 

Q: As the LED display is made of lots of tiles, there must be more flexibility in size and aspect ratio. Right?

A: Size and aspect ratio is a little bit more complex for LED displays than projection.  Due to their modular setup, there is no limit to the overall image size for LED displays. True. But this is where it can be more complicated than projection.  When looking at the size and aspect ratio, you also need to consider your content and desired resolution.

The LED panels that make up an LED display are a certain aspect ratio.  If the same number of LED panels are used horizontally and vertically – it will retain that same aspect ratio.  For example, Optoma LED panels are 16:9 aspect ratio.  A display of 10x10 panels would keep the aspect ratio the same.  But if the customer wanted a specific width and height, the aspect ratio may not be 16:9 and it would alter the resolution – as there would be more or less pixels depending on the size chosen.

Resolution is determined by the size and the pixel pitch of the LED display – that is, the distance between each LED diode/pixel in the panel.  The narrower the pixel pitch, the greater the resolution of this panel. 

Pixel matching the content to the native display resolution is always the best option. But if the content resolution varies or cannot be known up front, Optoma has a range of image scalers which use the exceptional HQView technology to give the best on-screen results.

So, if people want a definite size, they may need to compromise on the resolution and aspect and/or create content at that resolution.  Optoma has simplified this for customers by offering a range of panels at specific sizes and resolutions. 

LED Screen





Screen resolution

FHD 1080P

FHD 1080P



Screen size (dimensions)

4 x 2.2m (180”)

5 x 2.8m (226)”

8 x 4.5m (361”)

10 x 5.6m (452”)

Customers can have custom sizes with different resolutions but they should try to ensure the overall display’s aspect ratio is consistent with its individual panels to ensure the image is not distorted.

Q: Why is it important to know where will the audience be?

A: The closer the audience is to the screen, the narrower the pixel pitch you need for them not to see individual pixels.  As a rule of thumb – for a 2.6 pixel pitch, the minimum viewing distance is 2.6m away, for a 2.0 pixel pitch it is 2m.  But this is not the optimal viewing distance.  We advise that the optimum distance if roughly the width of the display.  So the best place to view a 5m wide display is 5m back.

One more thing.  You also need to think about the viewing angle.  Better quality LEDs have a wider viewing angle. If your audience will be viewing the display far off-centre, you need to make sure the diodes have a wide viewing angle, which ours do.

Q: How accessible will the display be after install?

A: Some LED displays are only accessible from the rear which would need substantial framework, designed and signed-off by structural engineers. 

All of Optoma’s out of the box solutions are designed to be mounted directly onto the wall using wood screws and are front serviceable with no cabling required to connect each tile.  This makes installation and servicing quick and efficient.  They also have 3-axis adjustments to mitigate uneven walls. 

If one panel gets damaged, it can be simply swapped out without having to dismantle the entire display. It is easier and cheaper to change this single panel within an LED display than for a LFD or videowall. 

Every display comes with a custom tool kit with everything needed to install, as well as spare LED panels and components.  This includes a unique suction device for removing individual panels which significantly reduces the potential for damage during installation and servicing.

Q: Does it need much servicing then?

A: No. Optoma LED displays need minimal maintenance.  There are no filters to clean.  Fluctuations in temperature and damp may reduce the lifespan of diodes so we advise to leave the display on standby to keep these warm and dry.  If there is a build-up of dust on the front of the display, you can brush this gently with a soft brush - but other than that, they need very little maintenance.

Q: What are the main pitfalls for installers?

A: One of the common pitfalls is that buyers look for the cheapest option and buy directly from a far East supplier.  This is high risk as these companies request payment up front and, when there are problems, provide no local support.  I would recommend choosing a trusted and established AV brand within Europe with whom they can be assured they would have support during and post install.

We can guarantee a single bin pick for LEDs.  This means that the LED panels all come from the same production run to ensure a consistency in colour performance and brightness across the whole display. 

Q: Anything else?

A: Once the size and resolution is set, this will determine what controller you would need.  All Optoma displays come with a controller and all cabling. 

Each controller has a fixed number of outputs to prevent bandwidth issues.  Optoma MCTRL660 is designed for screens with a maximum resolution of 1080p.  It has four outputs dividing a 1080p screen into four signal runs.  A 4K resolution display would need a controller with 16 outputs – four times that of 1080p – so would use Optoma CTRL4K.  If you need full redundancy, you would need an extra controller and cabling.

The only other thing to consider is the power needed for the display.  This is dependent on size and brightness.  We advise customers on the maximum consumption based on maximum brightness so they can arrange for the electrics to accommodate this. 

Optoma has a range of ultra-thin, 16:9 native aspect ratio LED displays.  These are easy to install, operate and maintain, and engineered for reliability and superior image quality.

Why choose Optoma LED displays

  • Local stock, local support & cost effective
  • High brightness, high-resolution indoor Full HD and UHD 4K LED displays
  • Easy installation and maintenance – surface mount and front access
  • Ultra-thin 56mm panel depth - discreet, space-saving design
  • Best-in-class processing and switching – HQUltra technology
  • Ultimate reliability


With an ultra-thin panel depth of only 56mm, Optoma LED displays are designed to take up less space, blending discreetly into any environment.

Easy installation and maintenance

They can be mounted directly onto a suitable wall using wood or plaster screws without a mounting frame. A simple, lightweight frame option is also available. Front access gives fast, low-cost installation and easy maintenance.

Fully supported

Designed, supplied and supported as a single solution, Optoma LED displays include everything you need – from cables to preconfigured processors for a hassle-free installation.

Scaling and switching

They use industry leading HQUltra 4K image processing technology for best in class picture quality and low latency video processing. Inputs can be switched seamlessly in as little as 0.25 seconds.

Is UHD really 4K?


With any new technology, the terminology can be baffling. And resolution terminology can be the most confusing of all!

Resolution is simply the number of pixels in an image. The higher the number of pixels, the greater the resolution and the better the image quality will be.


Resolutions are as follows:

  • UHD 4K (3840 x 2160) pixels
  • WUXGA (1920×1200) pixels
  • Full HD 1080p (1920 x 1080) pixels
  • WXGA / HD Ready (1280 x 800) pixels
  • XGA (1024 x 768) pixels


Optoma 4K Ultra High Definition (UHD) projectors provide four times as many pixels as Full HD 1080p. That’s 8.3 million on screen pixels (3840 x 2160) bringing greater realism to every scene with increased depth and light and shadow detail for a truly immersive experience.

The UHZ65, UHD60, UHD550X and UHD65 all use a 4M pixel chip.  The latter 4K UHD models - UHD40 and UHD51 use a 2M pixel chip. But Optoma UHD 4K projectors do not pixel shift in the same way as the 3LCD ‘4K enhanced’ projectors from Epson and JVC.

To get your head around this, let me give a simple overview of how each technology works.

A projector using 3LCD technology splits the white light from its lamp into three colour beams and directs each to their own LCD panel to create the image to be projected.

At the heart of every Optoma projector is a DLP® chip. Developed by Texas Instruments, this chip has millions of microscopic mirrors, each measuring less than one-fifth the width of a human hair and each corresponding to one pixel on the final projected image. A spinning colour wheel made up of coloured segments is placed between the light source and the chip. The mirrors are then turned on and off perfectly in time with the right colour – allowing the projector to display a total of 16.7 million different colours for a fantastically vibrant, life-like picture. By using mirrors rather than LCD panels, DLP projectors are shown to have better pixel alignment and therefore show a sharper image.

DLP chip

Optoma’s 4K UHD projectors with over four million mirrors (UHD60, UHD65, UHZ65) deliver two discrete pixels for each mirror. UHD40 and UHD51 deliver four discrete pixels for each mirror.  The inherent fast switching speed of the DLP chip and Texas Instruments’ latest XPR™ technology allow the projectors to display the full 8.3M pixels to the screen from these pixel chips. This happens so fast that the eye blends them into one image.

The ‘4K-enhanced’ 3LCD projectors from Epson and JVC use native HD 1080p chips (1920x1080). To achieve ‘4K-enhanced’ they project a 1920x1080 image, then on the next refresh of the chips a second 1920x1080 image is off-shifted diagonally and overlaid onto the first. The total number of addressable pixels in this process is 2x (1920x1080) = 4.15 million - half of the 8.3 million in a native 4K signal.

The Consumer Technology Association (CTA) defines 4K UHD resolution as 3840 x 2160 or greater than 8 million addressable pixels. For projection systems, 4K and 4K UHD resolution should be defined by the on-screen counting of pixels or the ability to see greater than 8 million dots.

With the full 8.3 million on-screen pixels, Optoma’s 4K UHD projectors meet the Consumer Technology Association (CTA) requirements for 4K UHD and CTA High Dynamic Range (HDR) compatible display standards.

Among the smallest 4K projectors on the market, Optoma’s 4K UHD projectors set a new benchmark in performance.


The pros and cons of a projector over TV

A projector can give you amazing gaming experience and a true cinema-like feel at home – but what are the pros and cons of choosing one over a big screen TV?


Size This is a major reason to go projection! Actors on TV look larger than life. Hang on a second – they ARE larger than life. Filling your entire field of view creates a completely absorbing experience.

Viewing a standard TV of 37 inches from the average sofa distance of nine feet, your eyes just cannot see all the detail in a 1080p image. Blow that up four times to 100 inches and you can see each strand of hair, every blade of grass. And this is where the benefit of 4K comes into play. A larger image benefits greatly from the added resolution. At that distance most people will see pixels on a 150-inch 1080p image, but not with 4K.

As seen on the graph below, at nine feet from the screen anything bigger than a 65” image will look better with 4K. Optoma projectors can produce images up to 300 inches.



Easier on the eyes You may think having such a large screen may hurt your eyes. Actually, it's the opposite. Filling a larger percentage of your visual field, and with less overall brightness, a big screen is actually more comfortable to watch and, just like in the cinema, the picture is also more immersive.

Space and setup Projectors can be used anywhere there is a power source, a flat surface and enough space. They are light and portable to be taken around to a friend’s house for a gaming session or an outdoor film night. A TV is less flexible to pop under your arm and take to your mates!

 Projectors can be ceiling mounted or simply placed on a table or shelf – and you don’t have to have a screen. You can project straight onto a plain wall. If you do want a screen - these come in all shapes and sizes. They can hang on the wall or be retractable, where the screen disappears into the ceiling or you can get a portable one that you simply pull up.

Short throw and ultra short projectors are ideal for gamers as these create a large image from very close to the screen or wall. Gamers are therefore behind the projector ensuring no shadows are cast across the image.


Projectors are, on the whole, cheaper than comparably sized Full HD TVs. Getting a TV larger than 100 inches currently costs around £30,000 (if you can find one to buy). Getting the same screen size and equivalent picture quality could cost as little as £500 with a projector.


Most home projectors have a built-in speaker – perfect to plug and play. And if you want to connect to an external sound system, you can with the audio output. 

Wireless connectivity

Optoma projectors can also work wirelessly up to HD quality using the optional WHD200.




Light can be a problem if the screen or wall is subject to direct sunlight. But Optoma’s bright home entertainment projectors are designed to be used with the lights on. And the darker the room, the more vibrant the image will be. 


Nearly all home projectors are lamp-based. Like any lamp-based light, these will eventually need replacing. How often will depend on how much use the projector has had and putting the lamp in Eco mode will greatly increase the lifespan of the light source from 5,000 to 8,000 hours*. Based on a 20 hours a week that equates to around 5-8 year’s use. 


After getting a projector all your friends' TVs will seem unbearably small.


Upsize that tiny TV; go projection!

A projector doesn't have to cost a lot of money, nor is it difficult to set up.  Interested? Read our blog on choosing the best projector for you