Projecting backgrounds behind your subject with the Wemax Nova 4K UST ALDP laser projector

Projectors have been a part of photography for a very long time. Originally, they were designed for boring your friends and family members with slides of your holiday snaps. Since then, though, projectors have become much more useful and now regularly play a creative or practical role in our photography and filmmaking needs.

We’ve shown how you might be able to incorporate projectors into your workflow before, using one as a full-screen preview monitor for video editing. This time, we’re going to take a look at the Wemax Nova 4K ultra-short-throw (UST) ALDP Laser projector with an Ambient Light Rejecting (ALR) screen as a sort of “virtual set” background projection system in the studio.

About the Wemax Nova

Despite costing $2,699, the Wemax Nova is considered an entry-level device as far as 4K laser projector tech goes. High-end ones… Well, they can get really expensive. Inside the box, it doesn’t come with much. There’s the projector itself, a remote control that takes a couple of AAA batteries, a power cable, and a little envelope containing your quick start guide and other paperwork. That’s it, basically.

But you don’t really need a lot. It’s a “smart” projector and runs Android TV, letting you access all the usual apps you’d use on your TV along with a bunch of sockets for connecting HDMI devices as well as USB storage. And don’t let that “entry-level” moniker I mentioned fool you. Entry-level for this sort of thing is still often better overall than a “really good” lower tech projector. So let’s talk about some of that tech and what it means.

Ultra-Short-Throw (UST)

The Wemax Nova is an ultra-short-throw projector. This means that you don’t have to have the projector on the other side of the room in order for it to cast an image on a screen. In fact, with the Wemax Nova, you can project an image size of 80″ when the projector is only 5.5″ away from the surface on which you’re projecting. Going up to 19.3″ away lets it project an image up to 150″. My screen is 92″ so it’s a little over 7″ away.

The benefit of UST projectors in the case of photography and filmmaking is that you can project backgrounds behind your subject to simulate shooting in whatever environment you wish while negating the one fatal flaw of traditional projectors that need to be at some range from the surface on which they’re projecting. They’re not casting any light on your subject. This also means that your subject’s not casting a shadow on the background.

The fact that they typically let you project pretty big at these short distances also means that as long as the surface onto which you’re projecting is large enough, you get much more freedom in lens choice before running into the edges of your projected background.

ALDP Phosphor Laser

ALDP is a technology developed by Appotronics and it offers a number of advantages over your typical bulb-based projectors. You get high light output with great energy efficiency. This means they can project bigger and brighter while using less power. It also means they generate less heat so the fans often aren’t as audibly loud (important if you’re using them to project a background for recording video – or, you know, trying to watch a movie in peace).

Not all ALDP laser projectors are ultra-short-throw (or even regular short-throw) projectors, though. The Wemax Go Advanced we reviewed a few months ago is also an ALDP laser projector, but it’s one that you’d position in the more usual way, several feet from the surface on which it’s projecting. So, make sure to check what kind you’re getting before you buy.

Aside from potentially offering super short throw distances, one of the big benefits of ALDP projectors is a much longer “bulb” life, typically in the region of 20,000 hours. The Wemax Nova boasts a rating of 25,000 hours in “View” mode. In projectors that use regular bulbs, you usually get somewhere between 1,500-2,000 hours on average and will dim as they age. Laser projectors last 10x as long or more and they’re much more consistent in light output over their lifespan and provide better colour fidelity. The Wemax Nova specifically supports HDR10 (and that LG 4K 10-bit HDR OLED demo on YouTube looks amazing on this thing) and covers 100% of the Rec.709 colour space.

The downside of laser projectors is that the laser can’t actually be replaced by the user like the bulb can in a more traditional projector. But given that it will last about a decade for a typical 40-hours-per-week viewing experience (at full brightness), the chances are that you’ll be in the market for a new projector by the time it dies anyway.

4K Resolution

I don’t really need to explain what this is, but it is interesting to understand how the Wemax Nova creates it. The Nova contains a single 1920x1080p DLP chip. So how does it create 4K? Well, it uses the same super-fast pixel shifting concept that we’re seeing in a lot of cameras lately. The Panasonic S1, for example, is a 24-megapixel full-frame mirrorless camera. But its “High Resolution Mode” allows you to shoot 96-megapixel images. It does this by taking a shot, then shifting the sensor slightly, taking another shot, etc. until it has all of the information it requires to merge together the final 96-megapixel result.

The Wemax Nova projects a 4K image in the same sort of way. It projects that first 1080p image, then it shifts it and projects another 1080p image, and keeps doing that until it’s produced the full 4K projection. Only, it’s doing it much faster than the sensor-shift tech in cameras used to capture images. The final result to our eye in the case of a projector is a smooth, clean 4K output.

This isn’t an abnormal technique in a projector at this price point and physical size, though. Even the Epson LS12000 that Linus recently got gooey over – which costs almost twice as much as the Wemax – works in exactly the same way to produce its 4K output. This method allows them to keep projectors relatively small and inexpensive while also minimising heat generation. And that heat one’s a biggy, because the more heat it generates, the more cooling it needs, which means louder fans and you don’t want that.

Connectivity

On the back, you’ve got the usual array of inputs that you’d expect from any half-decent projector these days. You’ve got three HDMI sockets, a Type-A USB socket for connecting external storage, 3.5mm audio output, 3.5mm A/V input, S/PDIF digital audio output, as well as an RJ45 socket for connecting it to your network over ethernet. And if you aren’t able to wire it directly into your hub, it also supports both 2.5GHz and 5GHz WiFi.

With just about everything outputting HDMI these days, it allows you to project all kinds of things to your screen to use as a background, images from your laptop or smartphone or even a live stream being beamed across the Internet.

It features 32GB of internal storage for apps and various downloads but you can also connect a USB 3.2 Gen 1 (AKA “USB 3.0”) external hard drive, SSD or memory sticks for storage of movies, TV shows and images or whatever else you might wish to project.

Operating System

Yes, that’s right, the Wemax Nova 4K has an operating system. Well, it is a “smart” projector, so it kind of needs one. In this case, it runs Android TV, complete with Google Voice Assistant and all of the apps you might be familiar with from your regular smart TV, like YouTube, Amazon Prime and Plex…

For the needs of photographers, the smart features aren’t particularly vital when you can just plug in a laptop over HDMI, although they can come in very handy. It means you can cast an image or mirror your screen to the projector over WiFi, which is useful if the computer you’re containing the files you wish to project isn’t really within easy wiring range of the projector. But the fact that it does have an operating system with smart functionality does mean that you can project pretty much whatever you want, whether it be online, on USB storage or on your local network over WiFI or ethernet.

About the screen

This is where projectors often fall down when it comes to photography. Even if you have a very bright projector, the moment you start letting in even a little ambient light into the room, you lose contrast and definition in your projected image. Images start to look dull and washed out. If you want to light your subject separately using continuous LED lights or strobes, then those, too, can impact your projection if you’re not very careful about flagging them off from hitting the screen, too. And even if you are careful, light can reflect off other surfaces and pollute the screen, too.

To overcome this issue, I’m using a 92″ Ambient Light Rejecting (ALR) screen. These work by reflecting the light that hits it back to the viewer in a more controlled way. They only accept light from certain angles and then send it back towards the viewer (or your camera) in front of it. Ambient light from the ceiling or windows (or your continuous LED lights or strobes) is rejected and doesn’t impact what you see on the screen nearly as much.

ALR screens aren’t perfect, though. While you can get a decent image to your eyes with an ALR screen when you’ve got the curtains open, the camera’s still going to see at least some impact of the ambient light in your scene. And if you have a subject in front of the projection, your camera settings are going to be such that the ambient light is potentially impacting them, too. So, you’ll still probably want to dim the lights way down, even if not completely off.

You’ll also still need to position the lights for your subject carefully. Any light coming from where you might normally place a projector is obviously going to be reflected, too. And you might still need to add a flag or two depending on the position of your lights, but given that you’re usually putting lights up above your subject and not below them, most of the light will generally be ignored. So, have those flags handy, just in case.

ALR screens don’t eliminate the issues of photographing a projection entirely, but they do negate many of them and will make your life a whole lot easier than trying to photograph a projection on a painted white wall or white backdrop on a stand.

Setting it up

My setup here is in the garage. I don’t shoot in a studio often enough to justify the cost of a “real” studio. The screen I have here is a motorised drop-down ALR screen that’s suspended from the ceiling. I can roll it up or drop it down at the press of a button. With the screen down I then just need something on which to place the projector.

The primary purpose of using a projector like this in front of your camera is for projecting a background behind your subject. So, the Wemax Nova being a UST projector means that it can be very close to the screen. At around a 5.5″ distance, it’ll give you an 80″ projection. This is a 92″ screen, so I’m going to move it just a little further away so it can fill it up.

Once we’ve moved the projector into place to give you the size of projection you’ll need, we have to focus it. There’s no automatic focus here like on the Wemax Go Advanced, so you’ll have to do it manually, but it’s easy enough to do. Then we run through the keystone calibration and we’re good to go.

If projecting backgrounds is something you plan to do regularly, you’re definitely better off making a more permanent setup in your studio, but as my setup illustrates, it is something you can pull out at will whenever you need it and then store away when you don’t.

Now that everything’s in position, setting it up depends on you. The standard route with an Android TV smart projector like this is to log into the Play Store and start installing the apps you need that aren’t there by default. For me, that just meant Plex. Log into YouTube, Amazon Prime, etc. and you’re pretty much good to go.  If all you’re using it for is projecting images from a computer then you can just go ahead and connect the HDMI cable and set it up as an “extended display” on the laptop.

If your laptop’s regular display is 4K, you could just mirror it. Mine’s 1080p which is why I went with extended to be able to get the full 4K into the projector. Either way, I prefer using Photoshop for projecting backgrounds with a projector because it means I can work with very high-resolution images, zoom them in and out as needed, and move them around to reframe what I’m putting on the screen and seeing through the camera, all while completely hiding the Windows UI.

The next challenge is setting the camera exposure. Because of the frequencies at which digital projectors work, not all shutter speeds are going to give a clean smooth image. If your shutter speed is too fast or too slow, then you’re going to see either bright bands where parts of the screen have refreshed too much during the exposure or dark bands where things haven’t been exposed enough.

For stills, this is a lot easier to deal with. You just adjust your shutter speed until it goes away. With the size I was projecting (92″), I had no problem getting good exposures at 1/50th, f/4 and ISO400. This one’s at f/5.6 because the bright highlights of this image were just a tad too bright.

For video, this can potentially become a bit more challenging, as the shutter speed (or shutter angle) that eliminates this issue may not (ok, let’s say it, it probably won’t) match up with the 180° shutter rule. The 1/50th of a second shutter speed I mentioned above also worked great for me when testing with 24fps video.

So, some experimentation will be required to find a frame rate and shutter speed/angle combination that you’re happy with depending on what you’re projecting.

So, what can we do with it?

As mentioned, I like using Photoshop for projecting still images onto backgrounds like this. It allows me to hide the Windows UI while zooming in and out and translating the image in the projection quickly and easily. I don’t need to move my subject and all of the lights, I just move the background on the screen behind the subject. And speaking of lights, for these images I used the Godox SZ150R RGB LED as my key light and the Godox ML60 (review here) as my fill/rim light.

As well as being able to project a static image, though, it’s basically acting as a computer monitor when plugged into the HDMI output of your laptop. This means you can project whatever you want onto it. Need a fake news broadcast in your short film and want to create that stereotypical look of an interviewee sitting in front of the New York nighttime skyline? No problem.

Then at the press of a button, you can switch that background over to a virtual studio set, swap out your actor and now you can shoot the other half of the conversation in the studio. How about a presentation with animated charts and graphs behind the speaker that keep up with what they’re saying in real-time? Of course, you can shoot this on a green screen and composite everything in post, too, but given that you have to create the graphics with either method, this could potentially save you a lot of time.

Or what about if you do want to shoot a subject in front of a green screen but don’t have one? Why not just project green onto the background and key that out instead?

Of course, if you’re using a projector, why would you bother shooting on a green screen and compositing later? I mean, the whole point of using a projector is that you can just put whatever background you want behind your subject at the point of capture.

And if you’re using RGB LED spots like the Godox SZ150R (this is why I used it), then you can get a little more creative with your backgrounds. You’re not limited to outdoors in the sun or obvious studio-like environments (like the NY Skyline example above). Instead, you can place your subject in all kinds of weird environments and match the colour with your LED lights to blend them right into the scene. This is the same idea as virtual sets used in TV shows like the Mandalorian – except on a much lower budget.

What can’t we do with it?

The big thing we can’t do with this type of projector is to project images onto our subjects. Yes, it’s a thing. Whether you love it or hate it, it’s been a pretty common technique for decades. For those that hate the technique, the fact that it’s so difficult to project onto a background without getting your subject in the way is a huge drawback. But for those that love the technique, this is the wrong type of projector for you.

Of course, there’s nothing wrong with mixing and matching the two. You can use a UST projector behind your subject to create whatever background you want and then a separate regular distance projector to put a pattern onto your subject, giving you the best of both worlds.

Even with an ALR screen, though, you’ll still want to be careful of light spill and reflections. I struggled pretty hard in the garage with reflections of the key and fill/rim lights bouncing off cupboards, the shiny metal surface of the table saw and various other things darted about the area. An ALR screen will compensate for a lot, but light coming from some angles will still find their way back towards the camera – after all, light from the projector does, so it stands to reason that light from other stuff at typical projector angles also will.

What to look for when buying a projector for backgrounds

If you’re buying a projector for the purposes of creating fake backgrounds behind your subjects, ultra-short-throw laser projectors are where it’s at for the least amount of fuss. They’re easy to position behind you’re subject without getting in the way and they won’t project light onto your subject, either.

You want to check the display connectivity options provided. These days, almost everything has either already switched to HDMI or is in the process of switching it. If you absolutely 100% need features like DVI or VGA then you might struggle to find it in a modern laser projector or may need to use an adapter to convert it to HDMI.

And talking about the display side of things, keystone correction is important. While most projectors come with at least some sort of keystone correction, you’ll want at minimum 4 point keystone correction and ideally 8 point keystone correction. 8 points will give you a better result if your screen or wall isn’t perfectly flat and can help to overcome slight bends and bows in the surface.

While perhaps not quite as essential for some, check that it has USB connectivity. Being able to quickly put photos and video files on a USB stick or SSD, plug it in and get them up on the screen means you don’t have to deal with the potential hassle of a separate computer.

If you’re going for a smart projector, check what operating system it’s running. Is it something pretty standard like Android TV that gives you access to the wide range of apps that you’re used to and possibly need in order to project the content you desire?

Also, check the network connectivity options. Do you need wired Ethernet? No? Ok, what about WiFi? 2.4Ghz isn’t generally going to be fast enough, especially if you want to stream 4K video at 60fps but 5Ghz can handle it. So, check exactly what WiFi capabilities it features.

One thing I haven’t really spoken about – at all – in this article is sound. If you’re going to be using this as a regular projector for watching movies when you’re not using it on shoots, does it have built-in speakers? Are they any good? Can you connect external speakers? What about Bluetooth speakers?

The speakers built into the Wemax Nova aren’t that bad at all, really. They’re Dolby Audio 30W DTS HD. It also has the option of both analogue or digital audio outputs using 3.5mm or S/PDIF, or I can connect to my Sony SRS XB33 speakers over Bluetooth. Do beware, though, that if you’re using Bluetooth audio, the picture and sound might be very slightly out of sync – but that’s just the nature of Bluetooth audio with any display device.

As mentioned, the typical “bulb” lifespan of laser projectors is around 20,000 hours with the Wemax Nova offering 25,000 hours and some ALDP laser projectors offering even more. So, check the lifespan vs cost to work out how long it’s going to last you and ultimately, how much it’ll cost you per year. A projector that costs 75% as much but only lasts 50% as long is going to be more expensive in the long term as it will need to be replaced much sooner.

Conclusions

It’s a fun technique and the Wemax Nova stands up to the task very well. It’s not a technique that’s going to be for everybody, though, and with the costs of UST projectors being relatively high (even for entry-level ones), it’s not one that most people will invest in just to have a bit of a play. You buy into projectors at this sort of price point because you have an actual need for them. And not many photographers or filmmakers will have that need for their professional work.

Going to this technology isn’t going to be within everybody’s budget, but if you’re a studio that’s regularly filming clients in front of backgrounds you want to be able to adjust on the fly without having to go through the hassle of building up (not to mention storing) a whole set, then it’s a viable investment.

Of course, when you’re not using it as a studio background, you can… Oh, I dunno, use it for boring stuff like watching movies or catching up on YouTube. So it’s not useless outside of studio situations. But for the purposes of projecting backgrounds for photography and filmmaking, the idea of using an Ultra-Short-Throw projector along with an Ambient Light Rejecting screen makes the process much easier, eliminating many of the issues of low light and light pollution that plague lamp-based projectors.

Despite being only an entry-level ALDP projector, the Wemax Nova works very well for this use case. It’s bright, doesn’t get in the way of the subject (or let the subject get in the way of its projection) and exposes well to the camera. You may have to play with your shutter speed so as to not conflict with the refresh rates of whatever you’re displaying, but this is true of all digital projectors, regardless of whether they use a laser or a bulb.

It’s also pretty awesome for watching movies on – and that will likely be its main use when not sitting in the studio (or uh… the garage, in this case) projecting backgrounds for photographs. Android TV works pretty well and is very responsive with the remote and I get all the same apps I get on my regular TVs throughout the house. The 5Ghz WiFi has also quick and has no problems streaming 4K videos online or across the network from my desktop PC.

If you’ve been thinking about picking up a UST laser projector, whether it’s for use in the studio projecting backgrounds or primarily for use at home for watching movies (with maybe occasionally use in the studio), then ultra-short-throw laser projectors are definitely worth a look. As I mentioned, they’re expensive even at the entry-level and so are the ALR screens but they’re worth it in my opinion.

The Wemax Nova 4K UST ALDP Laser projector is available to buy now for $2,699 and is shipping now.

Huge thanks to fellow photographer, John Anderson for daring to step on the other side of the lens for a change so that we could have a good play with this!