I’ve spent the past months testing the Elegoo Mars 4 Ultra’s limits and seeing where it does– or does not– improve on the Mars 4. I’m excited to keep making more prints with it, although some upgrades feel necessary to let the Mars 4 Ultra really shine.

The Mars 4 Ultra is a great entry-level printer for people who want quality, but don’t need absolute perfection and don’t want to spend time chasing after it.

Although it’s not as large as the Elegoo Saturn series, it does champion the best quality on the market for hobbyist resin printers. But there is a downside: the ACF film in the resin vat.

Good budget resin printer overall
ELEGOO Mars 4 Ultra


  • 7-Inch 9K High Resolution LCD
  • Laser-carved Build Plate
  • Open Space GOO Format
  • Built-in 4G RAM
  • Built-in Wi-Fi Connection & High-Speed Wifi Transfer
  • 4-point Leveling System
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We earn a commission if you make a purchase, at no additional cost to you.

Overall, the Mars 4 Ultra is still an amazing choice for beginner or intermediate users. It’s a reasonable price, has good quality, is built well, and even has some extra features thrown in to make it worthwhile over the Mars 4.

In my hands-on review, I’ll show you my print results from my tests, show you the key features of the Mars 4 Ultra, and how they actually impact your printing experience.

Elegoo Mars 4 Ultra Review: Summary

Let’s start by going over the main selling points and drawbacks of the Mars 4 Ultra. 


  • Extreme high quality
  • Fast and easy setup
  • Stable 4-point build plate for less frequent releveling
  • Wi-Fi connectivity
  • Updated touchscreen UI


  • ACF film causes softening effect in final prints
  • Leveling may be a problem for beginners
  • Incompatible with Elegoo Mars Mate Air Purifier

Assembly and Setup


Similar to other Elegoo Mars machines, assembly consists of removing a couple protective films, screwing on the build plate, and putting on the cover. There is really nothing more to it.

It will probably take you more time to assemble the rest of your resin setup than to get the Mars 4 Ultra up and running.

My setup involved two DIY wash containers, one with water for a preliminary wash and another with 95% isopropyl alcohol for a full wash. I also have a SUNLU curing station to finish the prints.

For removing prints during testing, I stuck to using the metal scraper provided in the box with the Mars 4 Ultra. 


The first problem I encountered with the Mars 4 Ultra was a too-thick leveling card. It’s actually made of a type of cardstock instead of being the thickness of an A4 piece of paper.

Elegoo’s instructions tell you to push down hard on the build plate while tightening the leveling screws to get a proper level. I did this with an A4 piece of paper and had good results. In theory, you might be able to use the leveling card provided if you’re able to push down hard enough.

I didn’t want to risk having a print stick to the FEP (or in this case, ACF) film, so I erred on the safe side by using the A4 paper.

Once you have the screws tightened, press set Z = 0 in the menu. 

Resin Pour

I used Elegoo’s standard gray resin. You can get better print results with a mixture of resins or a higher quality resin, but I wanted to stick with this one because it’s widely accessible.

I shook the bottle for around 2 minutes before pouring it into the vat until the outlined max line. I personally didn’t wait until all the bubbles surfaced and popped, and it didn’t seem to cause any issues.

Testing & Results

Test #1: Elegoo Rook

My first test print was the Elegoo Rook which comes preloaded on the USB. I wasn’t sure what to expect yet, so I went overboard in ensuring bed adhesion by increasing the bottom-level exposure time all the way to 35 seconds.

That ended up being the one real issue with this print. It definitely stuck to the plate, and getting it off after the print finished was a struggle. I started by using the metal scraper and trying to pry it off using a wiggling motion and significant force.

Then I applied some isopropyl alcohol, and when that didn’t work, I poured hot water on the build plate to soften the resin. The scratches and scrapes pictured around the base are from trying to get it off the build plate.

The detail was decent despite only washing for a minute in total. However, I did notice that the text was softer than it could have been. I suspect this is due to the ACF film– more on that later.

One thing that I want to highlight from this print is that any model with a flat base as part of the final product is going to have the pattern of the build plate on the bottom.

Test #2: Queek Headhunter and Base

The next test print was a Warhammer 40K-inspired model and base. It’s called a Queek Headhunter, styled after the Skaven. I chose it for the small size, detail, and dynamic pose. Thankfully, it adhered to the bed and the print completed successfully.

Quality-wise, there were only two problems: the base was mildly chipped upon removal from the build plate, and some supports were difficult to remove. 

Of course, neither of these can be attributed to the printer. It took 7 hours to print from start to finish.

I was impressed by the small-scale detail the Mars 4 Ultra was able to capture. My camera struggled to capture it, but there was even a braided texture on its necklace.

Test #3: Ball-Jointed Doll (BJD) Head

My third test print was not so lucky. I chose to print the face plate and head cap of a ball-jointed doll (BJD). I felt like it was a good fit for the printer, seeing as the ACF film’s softening effect minimizes layer lines and the high resolution would be much appreciated in a BJD model.

Although the most important details of the print came out fine, there were major delineation issues around the edges. 

With temperatures dropping to well below 0 outside, and this print finishing late into the night, I actually suspect this was the cause rather than improper supports or another issue.

Test #4: Ornate Mew

My last print was a highly detailed miniature of Mew. With fine-tuned settings and no user errors in the way, it was the perfect final test for the Mars 4 Ultra. The main purpose of this print was to see how much of an issue the frosted ACF film could be for prints that need sharp detailing.

In my opinion, the high resolution produced a fantastic model: I wish there was just slightly more sharpness on the ornate detailing, but it’s still a great quality print.

It’s a beautiful piece, but the details are softer compared to what they should be in an ideal world.

The Mars 4 Ultra is a very capable printer and the ACF film is its Achilles heel. Although I was still impressed with the prints I was able to make, a replacement film might be in order. That being said, high resolution isn’t the only thing the Mars 4 Ultra has to offer.

In the rest of the review, I’ll cover the main design and features before giving you one final judgment.

Design & Features

Frame & Form

The Mars 4 Ultra is almost identical to the earlier Mars 4 in design, with the main visible difference being the translucent black cover.

It has a modest build volume of 153.36 x 77.76 x 165 mm. To put that into perspective, you could print a small squadron of 4-5 minis, or a couple larger busts. It’s not a lot, but it works if you don’t have high production needs.

Actually, the smaller build size helps the Mars 4 Ultra pump out insanely high-quality prints, since the pixels are spread out across less space— more on that later.

There is only a single Z-rail holding up the build plate, which is fine given the small size. All in all, it’s a robust and functional design on par with the rest of Elegoo’s resin printers.

Touchscreen and UI

Unlike some of Elegoo’s other machines, the USB port has been moved to the front. It’s a minor change that I’m personally a fan of, since it makes uploading files much easier.

Elegoo also updated the UI of the Mars 4 Ultra’s touch screen compared to the older Mars 4. 

There were some grammar errors (e.g. “deleted” instead of “delete” and “canceled” instead of “cancel”) and minor inconveniences, but it looked modern and was laid out reasonably well. After the initial setup and print, I had no issue navigating the menu.

One of my favorite features was the ability to edit printer settings right in the menus. Sure, it’s not a must-have, but it was helpful when I was dialing in things like the bottom exposure setting.

During a print, you can see all kinds of helpful metrics by tapping on the progress bar mid-print.

I like to pause my prints around the 20-30% mark so I can check that they’ve adhered to the bed properly, and the menu didn’t make me jump through any hoops. 

Textured Build Plate

The build plate on the Mars 4 Ultra is made of a textured aluminum alloy. None of my prints failed to adhere, and I used the provided metal scraper to pry them off the plate.

It’s easy to scratch if you’re using a pocket knife, putty knife, or metal scraper, but it won’t affect your prints unless you’ve damaged it to the point of a metal pileup. It just needs to be reasonably flat to function, and you can actually machine it flat as necessary.

More important than the build plate material is the joint. It uses a 4-point system, compared to the 2 points that earlier Elegoo models had. The 4 screws only take slightly longer to level, but adds extra security to make sure your bed won’t un-level itself through use.

LCD Screen

The LCD screen, in tandem with the small build size, is the defining feature of the Mars 4 Ultra. It’s advertised as having a 9K resolution.

What’s actually important is the micron size of each pixel. Smaller pixels usually means higher print quality, and the 8,520 x 4,320p resolution on a small LCD means the Mars 4 Ultra has 18-micron pixels.

At least at the time of writing, this is the highest possible quality you can get from a consumer resin printer. It’s better than competitors like the Phrozen Mini 8K’s 22 microns, and the Saturn 12K’s 19 x 24 microns.

It also utilizes a Fresnel lens, which is becoming increasingly common in resin printers. In layman’s terms, it’s more effective at getting the UV light exactly where it needs to go.

Resin Vat and Film

At the end of the day, the actual vat part of a resin vat works more or less the same for every printer. I will say that the tapered edge makes it much easier to pour resin back out of the vat.

What you really need to pay attention to is the Mars 4 Ultra’s use of ACF instead of a FEP screen. ACF is becoming the go-to for resin printers, and it does come with some advantages.

The main benefit is that it releases easier, potentially allowing for higher print speeds. Unfortunately, it’s also frosted unlike the crystal-clear FEP and nFEP films of the past. The result is degraded quality and softer, less ‘crisp’ prints.

There are a lot of claims floating around that ACF is strictly better than FEP, especially by companies that are pushing the change in their marketing material. However, there is a very real concern of degraded quality when using ACF.

Whether or not this matters really depends on you.

If you’re someone who doesn’t want to mess with settings and anti-aliasing to minimize layer lines, the softening effect could be a bonus. It makes the layer lines less apparent, even though it also degrades quality.

The thing is, you may not notice a difference in many detailed prints.  

I found it a little bothersome for my BJD prints because of all the smooth surfaces; for the Warhammer-inspired mini, it didn’t matter at all.

Unless you’re taking a magnifying glass to every print, the Mars 4 Ultra’s print quality is already astounding.

Ultimately, I think the ACF film is a misguided decision but isn’t a real problem for most casual users. If it really comes down to it, swapping it for a FEP film is cheap and takes mere minutes.

Tempered Glass Screen Protector

I was relieved to see a tempered glass screen protector listed as a feature. The Mars 4 Ultra aside, I think every modern resin printer should include at least a basic screen protector.

The reality is that spills happen, and it can be an expensive mistake. Although you can buy and install a screen protector on your own, it’s much easier— especially for newbies— if it’s already included.

It does seem like the protector is underneath the black tape rim, which will make it a pain to replace. There’s also a possibility that I didn’t receive a screen protector with my printer at all.

Either way, it’s a strange decision.

Wi-Fi Connectivity

The Mars 4 Ultra’s Wi-Fi connectivity is another direct upgrade from the original Mars 4. Especially since the provided USB is low-quality, Wi-Fi turned out to be one of my favorite quality-of-life features.

It’s easy to find the Wi-Fi option in the touchscreen menu and connect. You can send files to your printer so long as your computer is connected to the same network.

Charcoal Filter

Elegoo has made a point to include a small charcoal filter in the box with their resin printers, and the Mars 4 Ultra is no exception. 

Let’s get this out of the way: the filter really doesn’t help with VOCs from resin.

What it does help with is the overpowering resin smell, and for that, it’s definitely appreciated. A setup where you vent the fumes into a filtration system or outside is what you need to maintain good air quality.

Sadly, the Mars 4 Ultra isn’t compatible with the large Mars Mate air purifier that Elegoo sells. It begs the question why the filter is named “Mars Mate” when it doesn’t work with most Mars models.

Software: Voxelab Tango vs Chitubox

The Mars 4 Ultra comes with a lifetime license to the Voxelab Tango slicer, which usually costs a pretty penny to use. There is a card in the box that includes a code for the slicer. Installers for Voxelab Tango and the free Chitubox Basic are loaded on the USB, so there’s no need to chase down install links.

I tried both slicers for the test prints, focusing on the features that are most commonly used and most helpful for the typical hobbyist. I imported, scaled, auto-generated supports, sliced, and sent the final file remotely for printing.

None of my test prints were really suitable for hollowing, but there were easy-access hollowing and drainage hole options in both slicers.

Although both slicers were totally functional, I liked the auto-generated supports in Chitubox a little more. For the models I used, Tango’s auto-generated supports were far heavier than necessary. I don’t mind trimming slightly, but I would have needed to spend time fiddling with settings and regenerating the supports completely to get the effect I wanted.

I will say that the visible support rods in Chitubox’s edit mode makes it harder to manually edit the supports. It wasn’t a huge problem with the minimally-supported Mew model, but it was less than ideal.

In fact, the editing workflow in Voxelab Tango felt better overall when compared to Chitubox. There are more robust options for manual editing and it’s easier to access features like compensate Z, hollow, labeling, build orientation, and so on.

The supports in Tango’s edit mode are represented by blue circles, which you can drag or click on to remove. You can also click anywhere on the model to create a new support pillar. There is also a perforated raft by default, which was an option I couldn’t even find in Chitubox Basic.

Frankly, there are plenty of resin slicers out there and many of them can get the job done. A lot of it comes down to personal preference and what you usually need out of a slicer.

Final Thoughts on the Elegoo Mars 4 Ultra

The Mars 4 Ultra is an amazing resin printer and stands out amongst other options because of its high resolution and brand-name quality. It’s especially great as an entry-level printer. Elegoo’s reliability, in-box supplies, and lifetime license for Voxelab Tango are all huge benefits for people just getting into the hobby.

At the same time, it has plenty to offer for more experienced or even professional users. It has more stable leveling and the addition of Wi-Fi to tip the scales away from the well-loved Mars 4. Large printers like those in the Elegoo Saturn series might be less accessible because of the sheer desk space they take up, while at the same time offering less quality.

Good budget resin printer overall
ELEGOO Mars 4 Ultra


  • 7-Inch 9K High Resolution LCD
  • Laser-carved Build Plate
  • Open Space GOO Format
  • Built-in 4G RAM
  • Built-in Wi-Fi Connection & High-Speed Wifi Transfer
  • 4-point Leveling System
Elegoo here Amazon here
We earn a commission if you make a purchase, at no additional cost to you.

Especially if you swap out the ACF film with FEP, the Mars 4 Ultra holds its own or surpasses most other resin printers on the market. The one thing it doesn’t offer is a large volume– so if that’s important for you, it may not be quite right.

For everyone else, the Mars 4 Ultra shouldn’t let you down.

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