Sony a7S III vs FX3: Which Compact Cinema Option is Best for You?


After a lengthy wait, Sony unveiled the a7S III, satiating years of desire for an upgraded king of mirrorless video. The release itself wasn’t so much of a shocker, even if the specs were top notch—perhaps even beyond expectations. However, the surprise came when just a short time after, Sony lifted the curtain on the FX3 as part of the Cinema Line. Borrowing bits from both the a7 series and the more traditional cinema cameras, the FX3 led many to ask the question: Should I get the a7S III or the FX3? 

TL;DR: For video purists, the FX3 is an easy choice because it brings loads of extra features along with the base design. Those blending stills or video, or in need of an EVF for handheld, eye-level shooting, will want the mirrorless form factor of the 7S III.

Today we hope to guide you through the selection process and help you make the best decision for your requirements. We will be making the assumption that if you are comparing these two models you are likely focused on video performance. 

Table of Contents

  • Image Quality 
  • Physical Design 
  • Audio 
  • Operation 

Image Quality: Top-Notch Specs for Both 

Before we even get into which camera you should pick, we should start with why you should get either. The answer is image quality. 

The a7S III and FX3 share many specs and features: 

  • 12MP Full-Frame BSI CMOS Sensor 

  • Internal UHD 4K up to 120p in 10-bit 4:2:2 

  • XAVC S-I and XAVC HS compression options 

  • Raw 16-bit Video Output via Full-Size HDMI 

  • Raw Video Recorded at 4.2K 60p using Atomos Ninja V/V+ 

  • Internal Full HD up to 240p 

  • Advanced phase-detect autofocus system 

  • 15 Stops Dynamic Range 

  • ISO Range 80-102,400 

  • S-Log3, S-Cinetone, and Other Picture Profiles 

If you haven’t seen the cameras, and had to choose solely on the spec sheet, you would likely be wondering if they were the same camera. That sensor does a lot of heavy lifting. When you look at the two cameras, you will clearly see that the difference comes in the ergonomics and design. 

Physical Design: Very Different Mindsets 

Just look at these two cameras. Obviously, there are some huge differences when it comes to physical design. A fun note is that the cameras have different finishes. The a7S III is a classic black mirrorless camera, while the FX3 takes on the dark gray persona of the Cinema Line. A very small thing, I know, but it does clearly show the target audience for each camera. 

More similarities between these two cameras are manifested in them having the same ports. Even the locations of these are quite similar. They each have the following: 

  • Full-size HDMI 

  • USB-C 

  • Micro-USB/Multi-Terminal 

  • Multi-Interface Shoe 

  • 3.5mm headphone jack 

  • 3.5mm microphone input 

On the opposite side of the camera, you will find the card slots. Both have dual CFexpress Type A/SD slots. It’s a unique feature by Sony on its newest cameras―and is super nice.



Elevated mirrorless form factor  Ultra-compact cinema camera design 


Built-in high-res EVF  Removable top handle with XLR inputs 
Familiar design to a7 series  Integrated 1/4"-20 mounting threads 
Customizable buttons for stills or video workflow  Fan for active cooling for longer shooting times
  Button layout optimized for video 
  Multiple tally lights on front and back 


Requires cage/rig for mounting accessories  No EVF 
Optional XLR Adapter needed for advanced audio  
No active cooling, overheating potential   


If you are planning on shooting mostly video, the FX3 offers so many advantages thanks to an optimized design. The only con, however, is huge: the lack of a built-in viewfinder. The a7S III is nice if you plan on switching back and forth between shooting both stills and video and working handheld with the EVF, but that’s about it. 


Jumping off one of the key differentiators of the FX3—the removable top handle with XLR inputs—we are going to talk about audio.  

Out of the box, the FX3 is the clear winner since it comes with a top handle with two XLR inputs. That’s huge for on-the-go video production, although this can be added to the a7S III with the addition of the XLR-K3M XLR Adapter. Technically, audio quality here will be the same; however, the ergonomics of the FX3’s top handle put it over the top. Most a7S III users will want to build a rig or cage to handle the system better when the XLR adapter is mounted in the hot shoe.  

We don’t normally consider price here but, in this case, I find it relevant. Buying an a7S III with the XLR adapter will cost a couple of hundred dollars more than an FX3, which comes with the XLR unit. If your default is to pick up the XLR adapter for the a7S III, it might make more sense to just go with the FX3 instead. 

Otherwise, both cameras have the usual 3.5mm headphone and microphone inputs. Both are capable of recording quality inside. 



This is where the decision gets tough and is likely the part where most people will need to look at their own preferred style. Among the biggest factors is the built-in EVF on the a7S III, which was removed to create the FX3. This makes the a7S III better for stills because the eye-level operation is a familiar form factor. The a7S III also looks like a mirrorless stills camera, meaning it can be a little more discreet for handheld operation. The EVF allows for better monitoring during bright days and provides an incredibly sharp, contrasty image. If you need an EVF, then the a7S III is a clear winner. 

Another interesting note is that the a7S III is completely sealed, since it does not feature a fan. This could mean in the worst weather conditions, the a7S III potentially might fare better. 

Where the FX3 excels is in the button layout and customization. The camera is designed for video first, and it gains things like a zoom rocker on the shutter release/record button for ergonomic control when working handheld. The top handle and 1/4"-20 threads are very much a video form factor and make a lot of sense for working handheld with accessories. The a7S III can get there, but requires a cage, which will add some weight. 

The way you plan to use your camera really depends on personal preference. 



We’re keeping this one short since both cameras offer the same photo capabilities. The a7S III is the easy choice because its layout is better suited to stills operation while still being customizable for video. The EVF and general design make it much more sensible for capturing stills. 


Final Thoughts 

Both cameras will serve you well. Pure quality out of these cameras is exactly the same in every way―you will be making your decision based on ergonomics and features. Anyone switching between stills and video should go with the a7S III. It also might make sense if you already are accustomed to the a7 form factor and are comfortable with it. For people who are buying a camera specifically to shoot video, you will be much better served by the FX3. 

If you still have questions or need some help, please feel free to reach out to our sales team or leave a Comment, below. 



Hey! I have an a7iii and do about 65% photo and 35% video but I’d like to eventually switch to 70/30 and be on the video side of things. I love both capabilities in terms of 4k120 and dual native iso. What would you guys recommend in terms of still doing sports photography along side videography? (I don’t need an evf)

If you don't need an EVF the answer is easy: go with an FX3. For sports photography and videography, depending on how you shoot, I personally would tend towards preferring an EVF. But, having an EVF is a personal decision on your part and one you are already familiar with since you have an a7 III already. The FX3 will win out for video in every way, especially since the fan will prevent overheating during longer shoots, like the length of an entire game.

I’ve heard the fx3 doesn’t shoot burst photos, what does that mean? Like pressing and holding the shutter or just pressing the shutter once and taking multiple photos? Thanks for the input!

The FX3 will actually do continuous shooting up to 10 fps. You may be thinking about the FX30. The FX3 has a physical shutter which allows for continuous shooting. The FX30 is electronic shutter only and gets limited to slower shooting.

hello, I don't have the best knowledge about the codex and these things but I know how to use a camera hehe. I´m thinking if the FX3 is the right choice, is the first one I thought of but I tend to have problems making a concrete decision hahaha. I have an a7RII and won't be needing any still. ill be using this camera only for videos. but is there any codex, or 422 any differences in a7SIII vs FX3... so! i need to know if i should go with a7siii or fx3 hehehe 

For only videos the FX3 is the more sensible choice. Sony has also given it some nice firmware updates that make it a touch better than the a7S III too. The only thing I would say is if you really love using the EVF of your current a7 since the FX3 does ditch that in favor of a more rig-friendly design. As for image quality they will be identical between the two cameras as the codec selection is the same.

I've been debating this choice for quite some time, and it keeps striking me that if a major selling point is that there are threaded screw holes in the FX3 then the comparison is getting ridiculous. The FX3's oversized top handle seems ridiculous as well, for a Rode shotgun in a hot shoe on the a7siii seems far more practical, and from a quality standpoint the recorded audio is identical. So truly, this is a head scratcher.

Hi Larry, it sounds like you have an easy decision! If you don't need the mounting points or see a need for the XLR handle then the a7S III seems like the better choice. Many people would gladly trade out the XLR adapter for the 1/4"-20 threads on the FX3 and the XLR handle does allow the use of a different class of mic (and potentially better quality audio). Once you start adding various accessories, such as timecode generators, monitors, audio receivers, etc. the 1/4"-20 points become invaluable. With the a7S III to do that you'll need to purchase a cage which adds bulk and weight.