Hollyland MARS 400S - Full Review
WHAT IS THE MARS 400S?
The Hollyland MARS 400S is a low latency wireless video monitoring tool. If you're a small film crew or a videography team, your director and other staff can remotely monitor what is being captured by the camera operator with minimum messing around.
You can connect up to two receivers to the transmitter natively and then up to four phones can monitor along with the main feed through the Hollyview app on iOS or Android. I'll take a look at the app later in the review.
In Hollyland terms, the MARS 400S is a consumer product. That makes sense when you check out some of their other offerings. Fortunately, however, it has many of the hallmarks of a professional device. It's a decent upgrade to the MARS 300 but carries a higher price tag. At the time of this review, it retails for about £600 whereas the MARS 300 sells for £450. Watch out though, as there are a few key areas when Hollyland chooses to limit this device to keep it well and truly in consumer territory.
IS THIS JUST AN EXPENSIVE VIDEO SENDER?
Short answer, no. An Amazon search of 'HDMI video sender' will bring up some units for less than £100. Don't make the mistake of thinking that these are similar products. That would be like comparing an Atomos Sumo to a 19" television. They both display images in a 19" frame, but they certainly aren't designed to do the same job.
You only have to hold the MARS 400S to know that this is in a completely different league. Build quality is better, image quality is outstanding, latency is consistently low, and IO is much, much better.
Hollyland MARS 400S transmitter front view
THE SPECS
INPUT / OUTPUT
Video - Unlike the MARS 300, which is an HDMI only device and the MARS 400 which is dual HDMI, the MARS 400S includes 3G SDI on both transmitter and receiver together with a full-size HDMI port. Admittedly, a lot of smaller consumer cameras don't use SDI, but many monitors and recorders do. If your camera inputs HDMI to the transmitter, you can use either HDMI, SDI or both on either receiver. Both ports output the video signal and can be connected simultaneously. This level of IO gives you a maximum of four devices monitoring one camera plus another four viewing on smartphones. That's pretty impressive if it all works reliably, that is. As another plus, both SDI and HDMI use high quality, gold-plated sockets. These are nice to see. I'm not too fond of it when manufacturers scrimp on connectors.
Firmware - You can update firmware via the USB-C port on the side of both transmitter and receiver. My devices had the latest firmware when I received them, so this isn't something I have tried, but Hollyland suggest this is a straightforward process that can be done in the field if required. A USB-C cable is supplied together with a USB-A to USB-C adapter in case your laptop only has USB-A outputs.
Battery Power - Battery power is through a Sony NP-F mount. The Hollyland documentation shows these units with an NP-F770 battery, but I've tested with NP-F550 batteries which also work OK. Using an industry-standard is such a plus point. I can switch batteries between some of my lights, my recorder and the MARS 400S. To get decent battery life, you'll need to use the NP-F770 battery which makes an otherwise slimline product a bit of a monster. It's a shame that battery technology hasn't kept up. Wouldn't it be lovely if the MARS 400S ran off two AAs?
External Power - DC power is through a high-quality socket with a thread to allow the power plug to mate securely. Technically the MARS 400S wants a 12V supply, but it will allow anything between 6V and 16V. Hollyland only expects you to use external power on the receiver as they supply one PSU. 12V supplies are not hard to come by, though, and I can happily use any of my Atomos power bricks with these products.
Antennas - RF is through a male SMA connector. Again, this is nice to see because it's standard and allows simple connectivity to higher performance antennas, including third-party products. It's the same connector you'll find on many wireless devices with an external antenna. You get a spare antenna in the box which I am now using on one of my studio lights because I lost that one.
Mount - Each unit has a female 1/4-20 tripod thread on the base. It's a sturdy metal thread mounted beautifully into the aluminium casing. You can fit the units vertically if you have a big rig and won't notice tech sticking 20cm up from the top of your camera. Alternatively, you can attach the metal bracket provided to mount horizontally to a cold-shoe. The main problem here is that the screen is facing downwards. You can't access the controls or see the signal and battery status which seems like an oversight as the transmitter is most likely to be battery operated and will need a visible display.
Hollyland MARS 400S Ports
VIDEO TRANSMISSION
The transmitter sends video on 5GHz using OFDM modulation. The exact frequencies used will vary from region to region. As soon as you turn the unit on, it searches for a clear channel. The receiver seeks out the transmitter, and that's it. You're ready to go. I'm not sure if Hollyland uses 5GHz due to bandwidth requirements or maybe as an alternative to the massively overcrowded 2.4GHz spectrum. It's the right choice but does suffer the same limitations as your 5GHz router will at home. Line of sight will work well, but the range significantly reduces if you need to go through objects. I performed a range test and can receive video over 100m down the road but struggle downstairs in our older Edwardian building, a mere 5 metres from the transmitter. The reduced range is a limitation of using 5GHz. In the use case of this product, I don't see this as a huge problem, but you might get more mileage out of 2.4GHz in certain circumstances. Having both radios would be nice if it were possible. If you need more range, you'll need to bump up to the Hollyland Cosmo 2000 which weighs in at £3,500. We're in consumer 5GHz territory here so do be realistic about how far away you expect to use a product like this.
VIDEO RESOLUTION
Resolution tops out at 1080p at 60fps. HDMI supports all standard resolutions down to SD and SDI is 720p and 1080p only. Resolution is auto-detected from the incoming signal, so you don't need to configure anything. You may wonder why this isn't a 4K device. At this price point, you won't get a wireless 12G SDI 4K transmitter. If you're willing to increase your budget by 8-10 times, you may have more luck. A Teradek Bolt 4K, for example, will set you back £6,000. Of course, it's nice to monitor in 4K HDR with 12-bit colour if that's what you're shooting, but you won't get it for £600. Your camera can record in 4K but downsample for the HDMI or SDI output giving your team an excellent quality FHD view. At this price, it's sufficient, particularly as many people will be monitoring on a native 1080p screen anyway.
Hollyland Transmitter SDI Connected
LATENCY
Latency is ever so crucial on wireless video. In an ideal world, monitoring has to be real-time, but low latency is always desirable. Do you remember at the start of this review I said that Hollyland class the MARS 400S as a consumer product? Well, this is one of the ways they distinguish this device from their professional range. The MARS 400S manual states latency is 'under 0.1 seconds'. This latency figure looks good on paper, but it's still 100ms and is a very noticeable lag in some circumstances.
The MARS offers three latency presets. They sacrifice image quality for improved latency, and in my testing, I managed 140ms on the high image quality setting using SDI on the transmitter and HDMI on the receiver. Changing this to the speed setting reduces this to 90ms. A decent decrease but still enough lag to prevent critical work like focus pulling. If you want sub 10ms latency, you'll need to use the aforementioned Cosmo products.
I do almost feel that latency is intentionally crippled. There are times when a £30 webcam connected via ethernet but streaming wirelessly to my smartphone can achieve latency as good as this. Don't get me wrong. It's not going to do it reliably and consistently like these will, but it does make me feel that the Hollyland products could do better.
Just a word of warning. If you've been watching other reviews on this product, you may have seen much worse latency figures. These results are where people have decided to connect the receiver to a consumer television where it's common for the HDMI input to have a latency itself. Not a fair test.
VIDEO QUALITY
Video quality is superb. Let's make no mistake. The receiver outputs video that is virtually indistinguishable from the source on any of the displays that I have, at least in low motion scenes. I tested this in my unboxing video. It's possible here to see slightly less control on the highlights, but this is a grade of S-LOG footage, and I matched the colour grade exactly between shots. I didn't adjust for a potentially hotter video signal as I wanted a fair comparison.
On paper, though, the distinctions between pro and consumer continue here. Although the transmission carries the full contents of the HDMI or SDI signal, including audio, the MARS 400S compresses the video to send it. The proline offers lossless video. The collateral states 'uncompressed' but I think this means lossless as I'm pretty sure uncompressed video at 1080p would require way too much bandwidth to send over 5GHz. Please comment below if you know precisely how these devices work in regards to compression. Details are sketchy on the Hollyland website.
COOLING
Remember that video transmitters such as this are not only encoding 1080p video in real-time, they're also doing it as quickly as possible. Encoding is CPU intensive work, so both units run a fan continuously when powered up. I hoped that the metal casing would act as a heatsink, but that's not the case. The fan isn't heat controlled. It on all the time and it's quite noisy. Not a problem if all you're audio is captured elsewhere through a lav mic or a boomed shotgun mic, but if you're recording audio on the camera, you're going to pick this fan noise up. Most external recorders also use active cooling. It's not usually a problem but could be for you.
SMARTPHONE MONITORING
As mentioned, you can connect one transmitter to up to four smartphones simultaneously and monitor video via the Hollyview app. The app is no-nonsense, and connecting is incredibly simple. Turn the transmitter on, connect to the wifi network using the password found in the menus and tap connect. The video starts within a few seconds. That's it. Tapping on the screen gives you a plethora of tools including a waveform monitor, histogram, focus peaking, zebras, mono colour, false colour, punch in and 3D LUTs to help when viewing log footage. You can grab individual frames and record the stream on the phone.
My only criticism of the app is that I found saving the recorded video to my camera roll caused a massive crash. I'm not talking about just an app closing. My phone completely rebooted back to the Apple logo. That said, there have been two updates to Hollyview since I received the products, so it's frequently developed and, presumably, regularly improved.
Performance-wise, it's much more hit and miss than using standard reception onboard the unit. Video glitches occasionally, even at close range, similar to a weak digital TV signal. However, it recovers well and retains the low latency, but it can be a little annoying at times. I guess this is the price you pay for having aggressively low buffer times. It's entirely usable and is a lovely addition to an already great product.
Hollyland Transmitter and Receiver
OTHER USES
As a consumer product, let's think like a consumer and consider other uses for the MARS 400S.
Recording - Although there is some risk in recording on a wireless transmitter, the quality is easily good enough in a pinch and given close range and line of sight, it's a perfectly viable option. I'll let you decide how you could use wireless recording as this opens up many possibilities.
Video Sender - This is not a video sender, but you can use it as one if you wish. It's an expensive way of doing it, but it does open up some fun options around sending gameplay, or you could even connect it to your graphics card.
CCTV - I connected up a GoPro and created a super high quality, wide-angle CCTV solution. Overkill and impractical but fun nonetheless.
CONCLUSION
The MARS 400S is a niche product. You'll know if you need one and if you do, this could be a tremendously useful tool.
It's beautifully made and works reliably. I've spoken in the video about how it differs from the professional variants that cost five to ten times as much. I know these may seem like unfair comparisons to make, but I also feel that a review like this should inform you of the limitations of the product. You can then decide if it's a limitation at all.
Thanks to Hollyview for providing this sample for review. All opinions on the product are entirely my own. Thank you for stopping by.