How Does the Samsung S20 8K Video Stack Up Against the ARRI Alexa

Samsung’s new S20 smartphone makes a lot of big claims with its 100X zoom capability, 108MP stills, and 8K video.  On paper this 6.2 inch mobile device sounds sorta like a gorilla filmmaker’s dream come true, but can a ‘phone’ that you can find with a 2 for 1 discount on a new service plan stack up against a professional camera like the ARRI Alexa – even the original Alexa 2K that is 10 years old?

Since 2020 has proven to be a pretty disastrous year, Potato Jet is reaching 10 years back in time for a little hindsight from 2010, pitting ARRI’s heavyweight entry into Digital Cinema against Samsung’s latest iteration of an idea that they borrowed from Apple to see if this new attempt at an iPhone killer can even enter into the same ring as a piece of technology that is old enough to be its grandpa.

Looks count big-time in the world of digital cinema so let’s see if this Samsung S20 has got what it takes to make an impact.

Like the Samsung S20, the ARRI Alexa was a revolutionary camera when it debuted in April of 2010.  Its simplicity and reliability made the switch from 35mm film to filming digitally a breeze, instantly becoming a Hollywood favorite ever since.

Ten years is a long time in the technology world, and on top of that the cellphone industry has been the driving force of a boom in the small sensor market for our handy little mobile devices.   With a mass of consumers eager to ditch their devices every 2 years or so for the newest, shiny personal toy, the demand is high for the latest tech that will keep customers on brand.

Let’s see how the original Alexa stacks up against the Samsung S20.

Resolution

The Samsung S20 comes in with a jaw dropping video resolution of 7680 x 4320, which is technically 320 pixels shy of 8K but let’s not nitpick over it. 

The ARRI Alexa, on the other hand, can only shoot in a 2K (2048 x 1080) which is around 1/16th the resolution of what this cellphone can shoot.  If you’re thinking  this is going to be a slaughter, you’re dead wrong.

Despite that little shortcoming, the Alexa holds up well against the S20; even though it is obvious which is which, the Samsung’s S20 has a razor sharp image by comparison. 

Cropping in on both images you can definitely see the soft image from the Alexa, but all it takes is a little sharpening in post to even things up.

This leads me to believe that although the S20 is producing an 8K image, there is a ton of post processing being done in camera to embolden the contrast to make the image appear much sharper than it actually is.

Colors

One thing that really holds back cellphone video is color information.  The media on a phone simply isn’t fast enough (yet) for manufacturers to ease up on the compression.  And the first thing to go when you’re trying to make file sizes smaller is color.

This isn’t very noticeable when you’re shooting outdoors at the beach, but throw some funky colors in there and watch the image from the S20 really start to fall apart and look awful.

The original Alexa captures color information in 12 bit 4444 meaning that it captures 73 billion colors compared to the S20’s 16 million colors.  That is a lot less color information in the S20 and you’ll definitely notice it when you start messing with the images in post.

Resolution has never been the main reason for shooting on the ARRI Alexa.  It is all about the sensors quality and ability to capture color.  You can do a lot with the Alexa in post.

Depth of Field

The imager on the ARRI Alexa is Super 35 sized which is a lot bigger than the sensor behind the tiny lenses of the S20.  The bokeh of the Alexa is a very pleasing to the eye and this also allows you, the DP, to focus the audiences attention toward what you want them to be seeing at that moment.

To get a similar effect on the S20, you could use a focal adapter and a DSLR lens.

Slow Motion HD

To level the playing field, Potato Jet pits these two cameras up against each other in slow motion HD – since both cameras have to drop down their resolutions to shoot at a higher frame rate. 

And this makes the mastery of the ARRI Alexa stand out even more.  The  HD image from the Samsung S20 is soft compared to the Alexa, and that has everything to do with the massive 8K sensor they’re using.  In order to cut the 8K image down to an high frame HD signal, the camera is throwing away all of that extra data as fast as it can; producing moire patterns, blocky edges, and all around just making a low quality HD image.

Since the Alexa can only capture 2048 x 1080 pixels, increasing the frame rate does not mean the camera is throwing information away.

Conclusion

Every few years, I get on this kick where I think my mobile can replace my professional camera.  I get my new iPhone (I tried Android for 2 years and hated it) and I’m instantly amazed with the clarity of the images I can shoot with my phone.  Then I buy a phone gimbal and a couple other accessories, and shoot a few things for fun with the idea that I’m going to make something amazing and new.

It’s when I get around to about 2-3 months in, and I’ve done nothing but email and text with my zippy new mobile that I have my moment of clarity.  Sure it looks good and the device makes filming some things very easy but I find myself using the in-phone camera less and less.

Even when the specs match, the quality of the mobile camera’s images never compare to my professional DSLR or Cinema Camera.  I’ve used anamorphic lenses, focal adapters, filters and everything else I can think of but I always turn back to my trusted, purpose build camera no matter what I’m shooting.

Nevertheless, my eyes still light up when I hear that I could be walking around with a 8K camera in my pocket that is ready to roll at the drop of a hat.  That’s why I was dying to know how the Samsung S20 fairs when it goes head-to-head with a 10 year old piece of technology like the ARRI Alexa 2K.

The ARRI Alexa has been used to shoot so many professional Hollywood movies, and it’s great to see that it can hold its own 10 years down the road.  One day, someone will make a cellphone that is better than any professional camera.  That could happen tomorrow or 30 years from now, but the technology is always getting smaller and easier to use.

I’m very impressed with the look of the Samsung S20, and all of the mobile device cameras that are new in 2020.  If you’re an independent filmmaker, don’t worry about what you’re shooting on, just focus on the content of what you’re making.

Steven Soderbergh has made a point of making a handful of his films on the iPhone, but none of them were as good as Tangerine (an independent movie shot on the iPhone 5s back in 2015).  If the audience can connect with the characters and the story that you’re telling, they’ll forget all about whether the images look as pretty as they could on a $40 million budget.

[source: Potato Jet]

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